fl ». l . .r I - I. ‘ \ } > ' , , , .,.._w.m..,4.,... \Illllllllllllllllllllllllllllljlllllll 3 1293 020 This is to certify that the thesis entitled A New Generafiew OJ, Fol/W Cpmposffis fw- h GMShMCTiOM 07L envy e&f;C{W+ BV‘(JQ‘)5 presented by S‘AQU \(o’c All A‘ V] has been accepted towards fulfillment of the requirements for ’ M~$- degreein C3V~l €510. V Major professor Date g ~ 4— 0" 0-7639 MS U is an Affirmative Action/Equal Opportunity Institution PLACE IN RETURN BOX to remove this checkout from your record. TO AVOID FINES return on or before date due. MAY BE RECALLED with earlier due date if requested. DATE DUE DATE DUE DATE DUE 5 2E9 6/01 c:/C|FlC/DaleDue.p65-p.15 A NH A NEW GENERATION OF POLYMER COMPOSITES FOR THE CONSTRUCTION OF ENERGY EFFICIENT BUILDINGS By Shaukat Ali Alvi A THESIS Submitted to Michigan State University In partial fulfillment of the requirements For the degree of MASTER OF SCIENCE Department of Civil and Environmental Engineering 2000 ABSTRACT A NEW GENERATION OF POLYMER COMPOSITES FOR THE CONSTRUCTION OF ENERGY EFFICIENT BUILDINGS By Shaukat Ali Alvi A new class of polymer blends is developed which, upon temperature increase, exhibits relatively high latent heat storage capacity without any major loss of mechanical characteristics. Based on a comprehensive investigations of numerous polymer systems, a blend was developed comprising of low-melt-temperature thermoplastic finely dispersed within a thermoset matrix. The thermoset matrix envelopes the fineithermoplastic particles and minimizes the adverse affect of their softening and melting on the overall blend behavior. At the same time, the fine thermoplastic particles retain their high latent heat storage capacity associated with their melting process. With proper selection of the low melt temperature therm0plastic, the polymer blend can provide relatively high levels of latent heat storage capacity within room temperature. Composites of such polymer blends reinforced with discrete fibers and processed through compression molding provide viable alternatives to gypsum board for interior sheathing of building walls. Replacement of gypsum board with such polymer blend composites can lead to major savings in heating and cooling energy requirements of buildings. To Saba Shaukat iii All me 511mg? [hauls 10 guidance 2 my wine extenshe Dr. Ken encourag ’/) and trait Mr. Siai research some at pmridi 0i m\ 0min: ma. (TI ._.. H l'SA‘; ACKNOWLEDGEMENTS All thanks and praises be to Almighty Allah. I am grateful to my God who gave me strength and patience to complete this research. My sincere gratitude and heartfelt thanks to my thesis advisor, Prof. Dr. Parviz Soroushian for his advice and untired guidance and supervision throughout the period I was busy in my laboratory work and in my written efforts. I am thankful to my advisor who gave me patience hearings during extensive meetings. I am also thankful to member of my thesis guidance committee, Prof. Dr. Neeraj J. Buch and Prof. Dr. Martin Hawley for their sincere and enthusiastic encouragement. Special thanks to Mr. Michael J. Rich, who advised me on all the laboratory work and trained me to undertake important tests in the composite center. I am also grateful to Mr. Siavosh Ravanbaksh who appreciated my efforts and encouraged me throughout the research work and on many occasions helped me in getting materials and rushing on some of the procurements. I am also thankful to Prof. Dr. Gilbert Y. Baladi, who always helped me in providing assistance in extending the laboratory facilities for my research work. My thanks to all the colleagues who gave me suggestions to improve the quality of my research work. The principles and concepts exercised in this project were originated from DPD, Inc. Their willingness to introduce this technology to us as well as their financial supporting for the project are gratefully appreciated. Special thanks for USA Department of Energy who undertook the provision of funds for this research. iv l at showed 10 complete I I am grateful to my parents and my family who prayed for my success and showed lot of patience during my commitments to studies and encouraged me to complete my studies. CHAPTER List of Tables-w list of Figures-aw CHAPTER 1 -IT\'II General—~— Problem SL2 ‘ Research Si 4 Objective at it 1.1 1.‘ 1 CHAPTER 3— Ti 3-1 Definition < 33 General—-—- 3-3 Basic Cont 3.3.] P13; 2.3.: Poi 3.3.3 P01 1 1.3.4 (312 ~4 Blending( 2.4.1 Mc ——————f * TABLE OF CONTENTS CHARTER. EASE. List of Tables ix List of Figures xi CHAPTER 1 -INTRODUCTION 1 1.1 General 1 1.2 Problem Statement 5 1.3 Research Significance 7 1.4 Objective and Scope 8 CHAPTER 2 — THEORETICAL BACKGROUND 9 2.1 Definition of Terms 9 2.2 General 12 2.3 Basic Concepts 13 2.3.1 Plastic 13 2.3.2 Polymers 14 2.3.3 Polymer Processes 25 2.3.4 Glass Transition Temperature 32 2.4 Blending Of Polymers 57 2.4.1 Morphology 61 2.4.2 Properties of Immiscible Blends 54 2.4.3 Making Blends 67 2.4.4 Properties of Blends 68 2.5 The Concept of Physical States of Polymers 70 2.6 Mechanical Properties of Polymer Composites 72 2.6.1 Strength 72 2.6.2 Elongation 73 2.6.3 Modulus 74 2.6.4 Toughness 76 2.7 Polymer Blends Processing and Theoretical Modeling 73 2.7.1 Compounding of Polymer Blends 73 2.7.2 Compatibilisation of Polymer Blends 81 2.7.3 Theoretical Modeling of Polymer Blend 84 Vi ————i CHAPTER 3- SPECIMENS, MATERIALS AND FABRICATION 89 3.1 Selection of Material 89 3.1 . 1 Polymers 89 3.1.2 Fibers 97 3.2 Fabrication 100 3.2.1 Mold 100 3.2.2 Compression Molding Machine 101 3.2.3 Mixing and Blending Facilities 102 3.3 Test Setup 105 3.3.1 DSC and other Thermal Test Systems 105 3.3.2 TGA Instrument 106 3.3.3 TMA Instrument 106 3.3.4 Environmental Scanning Electron Microscopy 107 3.3.5 Tensile Tests 107 3.4 Preparation of Samples 108 3.4.1 Slabs without Compression Molding 108 3.4.2 Slabs with Compression Molding 109 3.4.3 Final Set of Slab Samples 110 CHAPTER 4— PRELIMINARY EXPERIMENTAL RESULTS 112 4.1 General 1 12 4.2 Characterization of Materials 112 4.2.1 Energy Absorption 1 12 4.2.2 Strength and Serviceability 115 4.3 Blending of Materials 1 16 4.3.1 Blending Methods 116 4.3.2 Blending PEG-34 with Thermoplastics 117 4.3.3 Blending with Thermosets 127 CHAPTER 5- EXPERIMENTAL RESULTS FOR FINAL POLYMER BLEND COMPOSITES 1 34 5.1 General 134 5.2 Sample Designation 134 5.3 Discussion of Results 135 5.3.1 Slab No. F1 -135 5.3.2 Slab No. Fl+2 136 5.3.3 Slab No. F2 140 5.3.4 Slab No. F3+1 145 5.3.5 Slab No. F4 149 5.3.6 Slab No. F5 153 5.3.7 Slab No. F6 158 5.3.8 Slab No. F7 163 5.3.9 Slab No. F8 167 vii CH CH .Ap —————'— , 172 5.3.10 Slab No. F9 5.3.11 Slab No. F10 5.3.12 Slab No. F11 5.3.13 Slab No. F12 CHAPTER 6— COMPARATIVE EVALUATION OF POLYMER BLEND 177 182 187 193 COMPOSITES CHAPTER 7— CONCLUSION 197 198 REFERENCES Appendix A viii 200 4.3 AA 45 4,6 4.7 ii 5.6 —-7_ , LIST OF TABLES Number Title: Bags 3.1 Selected low melt temperature of thermoplastics 90 3.2 DSC Test Results for Polyethylene Glycol of 95 different Molecular weights 3.3 Materials used to test the blend behavior with PEG-34 95 4.1 DSC test results for low-melt-temperature thermoplastics 113 4.2 Materials used for blending with PEG-34 (binder materials) 1 16 4.3 PVA-16: PEG-34 blend compositions and DSC test results 119 4.4 Description of the softening and melting behavior of PVA-l6+PEG-34 (5 0+50) with temperature increase 120 4.5 PVA-3 7: PEG-34 blend composites and DSC test Results 121 4.6 Softening Temperature of PVA-37: PEG-34 (50:50) with temperature increase 124 4.7 DSC Test Results for Different Polyester 19 A Unfilled + PEG-34 Blends ' 131 4.8 Flame Retardant Polyester: PEG-34 Blend Compositions and DSC Test Results 133 5.1 Thermal properties of Slab No. F 1+2 137 5.2 Thermal Expansion coefficient of Slab Fl+2 138 5.3 Tensile Test Results for Slab Fl+2 139 5.4 Thermal properties of Slab No. F2 142 5.5 Thermal Expansion coefficient of Slab F2 143 5.6 Tensile Test Results for Slab F2 144 ix 5.7 5.8 5.9 5.10 5.11 5.12 5.13 5.14 5.15 5.16 5.17 5.18 5.19 5.20 5.21 5.22 5.23 5.24 5.25 5.26.. 5.27 5.28 5.29 Thermal properties of Slab No. F 3+1 Thermal Expansion coefficient of Slab F 3+1 Tensile Test Results for Slab F 3+1 Thermal properties of Slab No. F4 Thermal Expansion coefficient of Slab F4 Tensile Test Results for Slab F4 Thermal Properties of Slab No. F5 Thermal Expansion coefficient of Slab F5 Tensile Test Results for Slab F5 Thermal Properties of Slab No. F6 Thermal Expansion coefficient of Slab F6 Tensile Test Results for Slab F6 Thermal Properties of Slab No. F7 Thermal Expansion coefficient of Slab F7 Tensile Test Results for Slab F7 Thermal Properties of Slab No. F8 Thermal Expansion coefficient of Slab F8 Tensile Test Results for Slab F8 Thermal Properties of Slab No. F9 Thermal Expansion coefficient of Slab F9 Tensile Test Results for Slab F9 Thermal Properties of Slab No. F10 Thermal Expansion coefficient of Slab F10 146 147 148 150 151 152 155 156 157 160 I61 162 164 165 166 169 170 171 174 175 176 179 179 5.30 5.31 5.32 5.33 5.34 5.35 5.36 Tensile Test Results for Slab F10 Thermal Properties of Slab No. F 11 Thermal Expansion coefficient of Slab F1 1 Tensile Test Results for Slab F1 1 Thermal Properties of Slab No. F12 Thermal Expansion coefficient of Slab F12 Tensile Test Results for Slab F12 xi 180 I84 185 186 189 190 191 LIST OF FIGURES m M figs 2.1 A linear polymer made of “A” atoms 14 2.2 Polymer structure showing pendant group 15 2.3 Repeat structure of polypropylene 16 2.4 One unit of repeat structure 16 2.5 A linear polymer 17 2.6 A branched polymer 18 2.7 A cross linked polymer 19 2.8 A star polymer 20 2.9 A structure known as dendrimer 21 2.10 Styrene monomers joined together to make polystyrene 24 2-11 Ethylene has two carbon atoms and four hydrogen atoms, and polyethylene repeat structure has two carbon atoms and four hydrogen atoms 26 2-12 Condensation polymerization 26 2.13 Anionic polymerization of styrene to make polystyrene 28 2.14 Step growth polymerization 29 2.15 Monomers forming trimer in step growth polymerization 3O 2-16 Monomers forming tetramer in step growth polymerization 31 2.17 Monomers forming pentamer in step grth polymerization 31 35 2.18 DSC device to measure Tg xii ~22 2.23 2.24 2.25 2.26 2.27 l\_) k.) 00 M 2.31 2.31 2.11 2.19 2.20 2.21 2.22 2.23 2.24 2.25 2.26 2.27 2.28 2.29 2.30 2.31 2.32 2.33 2.34 2.35 2.36 2.37 2.38 2.39 Plot showing heat flow vs. temperature 37 Plot showing Tg 38 Drop in heat flow during DSC test 39 Heat flow during melting 41 The DSC plot showing Tg, To and Tm 42 Material used as plasticizers 45 A heat vs. temperature plot for a crystalline polymer, on the left and an amorphous polymer on the right 48 Flexible backbone of polymethyl siloxane 50 Stiff backbone of poly (phenylene sulfone) 50 Making polymer process able, ether group is added 51 Pendant group for getting high Tg 52 Effect of pendant groups on Tg 52 Series of methacrylate polymers showing different Tgs 53 Atactic polystyrene 54 Schematic curve of typical DSC plot of an amorphous polymer 54 Effect of temperature and cross-linking on modulus 55 Immiscible polymers 58 The phase morphology of HIPS (high impact polystyrene) 58 Immiscible blends of poly (ethylene terephthalate) and poly (vinyle alcohol) 60 Lamellae of PET and PVA 60 62 Relative amount of polymer B in the immiscible blend xiii ‘41.! 2.41 l J 5< 2.40 Processing under flow in one direction turns the spheres into rods 63 2.41 Bonding of different blocks together 65 2.42 Phase boundary being shown between two immiscible materials 65 2.43 Material grafted to backbone 66 2.44 Linear relationship of Tg versus blend Proportion 68 2.45 Non linear relationship of Tg versus blend proportions 69 2.46 Tensile strength of the specimen 72 2.47 Compression strength of specimen 73 2.48 Test for flexural strength of the specimen 73 2.49 Stress elongation curve 75 2.50 Stress strain curve 75 2.51 Area under curve is showing the toughness 76 2.52 Comparison of toughness 77 2.53 Deformation of Dilute Droplets in a shear Field 79 2.54 Examples of Mixers and Extruders used in Polymer Blend Compounding 80 2.55 Factors Contributing To End Use Properties In Melt Compounded Blends, Highlighting The Role Of Compatibilities 83 256 Schematic structural elements in polymer blends 85 2-57 The Takayanagi Models; (a) Parallel: (b) Series 87 2.58 The Takayanagi Series-Parallel Model 88 3.1 The Shape of the mold 100 3-2 The curve showing various stages of compression molding 102 xiv 4.4 5.4 53. 5.6 3.3 3.4 3.5 3.6 3.7 3.8 3.9 4.1 4.2 4.3 4.4 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 5.9 5.10 5.11 Extrusion machine Heating and mixing set up for this study DSC Test systems TGA instrument TMA Instrument Environmental Scanning Electron Microscopy Tensile strength testing machine A typical DSC test result for PEG-34 Test result for Epoxy EC-428 + PEG-34 (50 : 50) Test results for Epoxy 932 + PEG-34 (70+30) Typical DSC Test results for Polyester 19 A Unfilled + PEG-34 (50+50) ESEM Test Result of Slab F 1 +2 with Glass Fibers ESEM Test Result of Slab F2 with Glass Fibers ESEM Test Result of Slab F 3+1 with Glass Fibers ESEM Test Result of Slab F4 with Glass Fibers ESEM Test Result of Slab F5 with Glass Fibers ESEM Test Result of Slab F6 with Glass Fibers ESEM Test Result of Slab F7 with Glass Fibers ESEM Test Result of Slab F8 with Glass Fibers ESEM Test Result of Slab F9 with Glass Fibers ESEM Test Result of Slab F10 with Glass Fibers ESEM Test Result of Slab F11 with Glass Fibers XV 104 105 106 106 107 107 108 115 128 129 130 140 145 149 153 158 163 167 172 177 182 187 5.12 6.1 6.2 6.3 6.4 ESEM Test Result of Slab F 12 with Glass Fibers 192 Tensile Stress-Strain Curves of Typical Blend Composites Versus Gypsum Board 193 Tensile Strength of Gypsum Board Vs. Typical Polymer Blend Composites 1 94 Thermal Energy Absorption Within room temperature ranges of Gypsum 195 Board Versus Typical Polymer Blend Composites Examples of energy saving resulting from replacement of gypsum board with polymer blend composite for sheathing of walls 196 xvi p8 CHAPTER I INTRODUCTION 1.1 GENERAL Innovations in engineering often involve clever use of new materials in a particular application. Our emphasis in building construction has been largely on the strength and fire resistance of materials, and also on strength-to-weight ratio and economy. We have so far distinguished between building materials used for serviceability and strength, and those used for energy-efficiency (i.e., insulating materials). The research reported herein seeks to formulate new building materials which combine the serviceability and strength functions with the ability to enhance the energy efficiency of buildings. The concept of selecting structural materials for energy-efficiency is common in other fields; for example, lighter materials are used to enhance the energy-efficiency of automobiles. The comfortable working environment provided by buildings requires consumption of great amounts of energy. It is thus felt that future generations of construction materials would be deveIOped with due consideration given to structural/serviceability requirements as well as energy concerns. Over millennia, humans have found ways to extend and expand their energy harvest, first by harnessing draft animals and later by inventing machines to tap the power of Wind and water. The watershed social and economic development of the modern world, industrialization, was accompanied by the widespread and intensive use of fossil fuels. This development freed human society from the limitations of natural energy flows by unlocking the Earth’s vast stores of coal, oil, and natural gas. By tapping these 7” ancient, concentrated deposits of solar energy, the rate at which energy could be poured into the human economy was enormously multiplied. The result was one of the most profound social transformations in history. The New River of energy brought astonishing changes and did so with unprecedented speed. The energy transformations experienced by traditional societies——from human labor alone to animal muscle power and later windmills and watermills—were very slow, and their consequences were equally slow to take effect. In contrast, industrialization and its associated socioeconomic changes took place in the space of a few generations. For much of its history, the United States was mostly self-sufficient in energy, although small amounts of coal were imported from Britain in colonial times. Through the late 1950s, production and consumption of energy were nearly in balance. Over the following decade, however, consumption slightly outpaced domestic production and by the early 19703 a more significant gap had developed.1 The efficiency with which Americans use energy has improved over the years. One such measure is the amount of energy consumed to produce a (constant) dollar’s worth of gross domestic product (GDP). By that measure, efficiency improved by 42 percent between 1949 and 1998, as the amount of energy required to generate a dollar of output (1992 dollars) fell from 21.6 thousand Btu to 12.5 thousand Btu.1 Nevertheless, a growing population and economy drove up the total energy. As the US. population expanded from 149 million people in 1949 to 270 million in 1998 (an increase of 82 percent), total energy consurnption grew from 32 quadrillion Btu to 94 quadrillion Btu (up 194 percent). Per-capita energy consumption rose 62 percent, from 215 million Btu in 1949 to 349 million Btu in 1998.1 wuchmdby oillostjttstova tomZZpaoait ”Marsha: thtshaieofelw Wrasse Mmmemiajum Someofflm,‘ comb“ form)“ “New 9::me 411mm Qk‘ ”N. ——f Energy plays a central role in the operation of the industrialized US. economy, and energy spending is commensurately large. In recent years, American consumers have spent over half a trillion dollars a year on energy.1 The energy is used in three broad sectors: the residential and commercial sector, the industrial sector, and the transportation sector. Industry, historically the largest consuming sector of the economy, ran just ahead of the residential and commercial sector in recent years, followed by the transportation sector. U.S. home heating underwent a big change. Over a third of all US. housing units were heated by coal in 1950, but by 1997 that share was only 0.2 percent. Distillate fuel oil lost just over half its share of the home-heating market during the same period, falling from 22 percent. Meanwhile natural gas and electricity gained ground as home-heating sources; the share of natural gas rose from about a quarter of all homes to over half, while the share of electricity shot up from only 0.6 percent in 1950 to 29 percent in 1997.1 In recent years, electricity and natural gas have been the most common sources of energy in commercial use. The use of energy brings undisputed benefits, but it also incurs costs. Some of these costs show up on consumers’ utility bills. The charges levied on consumers by an energy producer (an electric utility with a coal—fired generating plant, for instance) are designed to cover the producer’s costs of building the power plant, extracting coal from the ground, transporting it to the power plant, crushing it to prOper size for combustion, maintaining the generating turbines, paying workers and managers, and so on. One important cost category that often is not reflected in consurners’ bills is energy-related environmental effects. These unwanted effects can be thought of as the ————f tail end of the energy cycle, which begins with extraction and processing of fuels (or gathering of wind or solar energy), proceeds with conversion to useful forms by means of petroleum refining, electricity generation, and other processes, and then moves on to distribution to, and consumption by, end-users. Once the energy has rendered the services for which it is consumed, all that is left are the byproducts of energy use, i.e., waste heat, mine tailings, sulfur dioxide and carbon dioxide gases, spent nuclear fuel, and many others, buildings as well. Keeping in View the energy crises in the world, an important requirement of modern material design is its efficiency towards energy saving without leaving harmful end products. It is in this context that the study reported herein seeks to introduce a new polymer based material which should reduce the burden on energy resources while meeting other design criteria such as strength and serviceability. Polymers are developing quite rapidly. Finding broader use in diverse fields of application, including civil engineering. The flexibility in their selection, design and properties is a key factor contributing to their growth. The advent of polymer composites has provided the construction industry with a tremendously versatile material, which can be truly tailored to meet challenging demands on diverse facets of its engineering prOperties. This research seeks to develop a new generation of polymer composites for use in building construction (emphasizing building panels); these composite would satisfy the relevant strength, serviceability and cost requirements, and would also be capable of storing (releasing) substantial heat energy at the upper (lower) limits of room comfort temperature. Building products made of such composites would not only function as conventional building components, but also store the excess heat available during warmer hours and release the heat when it is needed during colder hours. The new polymer system is designed to meet certain strength and serviceability requirements and also help control energy consumptions. This investigation is concerned with the latent heat associated with phase transition of materials. Water is a good example for explaining this point. At low temperatures below freezing, water is in solid state and behaves in totally different manner than at higher temperatures when in liquid or gaseous states. If we heat ice, it absorbs energy and in doing so changes its physical state from solid to liquid. If we continue heating water, it will be converted into gaseous state and absorbs more heat during this process. Now if we reverse the process, reverse phase change occurs, which is accompanied with release of energy. The idea of heat absorption and release during phase transition is central to this investigation. Polymers also absorb and release heat as they undergo phase transition, one such transition occurs during softening and melting over a range of temperature. If we select polymers from groups which have melt temperatures around room temperature, they can absorb excess available heat and release it when necessary. This function helps stabilize the interior temperature and release the pressure on energy resources. The goal here is to use the high latent heat of polymers while using blending techniques, produce a polymer based system which remain solid and serviceable as one of its constituents melts. The result would be a building material which meets relevant serviceability and strength requirements while providing substantial heat storage capacity for improved energy-efficiency. 1.2 PROBLEM STATEMENT The design of structures is done while taking into considerations different aspects of their serviceability and safety. One of the most important is the energy demand for heating and cooling. Energy use reflects on our selection of insulation materials, and heating and air conditioning systems. This project seeks to conserve energy by developing polymer-based materials which play dual role as functional building component and heat storage system. The new material should provide the following characteristics:- a. High capacity for heat storage (and release) within the comfort range of temperature (for energy efficiency). b. Strength, toughness and serviceability. c. Desirable workability (for ease of construction and maintenance), versatility and aesthetics. d. Environmentally friendly. e. Competitive in terms of initial cost and superior in terms of life-cycle cost. f. Durable, ultraviolet resistant, fire resistant, dimensionally stable and moisture resistant. ——’i 1.3 RESEARCH SIGNIFICANCE Polymers and polymer composites are versatile materials which can strongly impact diverse aspects of building construction. Humans have taken advantage of the versatility of polymers for centuries in the form of oils, tars, resins and gums. However, it was not until the industrial revolution that the modern polymer industry began to develop. In the late 18305, Charles Goodyear succeeded in producing a useful form of natural rubber through a process known as “vulcanization”. Some 40 years later, celluloid (a hard plastic formed from nitrocellulose) was successfully commercialized.2 Despite these advances, progress in polymer science was slow until the 1930s, when materials such as vinyl, neoprene, polystyrene, and nylon were developed. The introduction of these revolutionary materials began an explosion in polymer research that is still going on today. Unmatched in the diversity of their properties, polymers are used in nearly every industry. Natural and synthetic polymers can be produced with a wide range of stiffness, strength, heat resistance, density, and even price. With continuous research into the science and application of polymers, they are playing an ever-increasing role in society. In construction industry, many types of polymers have been introduced for a number of applications like windows, additives, coatings etc. This research seeks to introduce a new polymer material for use as interior sheathing of walls and ceilings, which complements serviceability and strength attributes with special thermal characteristics for energy- efficient building construction. Presently gypsum board is used in interior sheathing applications. The new polymer-based material which replaces gypsum board is a blend of different polymers. This material exhibits a solid-state phase transition with large latent heat absorption and also provides desirable mechanical and physical characteristics to —i—i satisfy various safety and serviceability requirements of building construction. The dual role of the new material as a normal building component and also as an energy-saving device presents the potential for major energy and cost savings. 1.4 OBJECTIVE AND SCOPE This investigation employed polymer blending and composite technologies to develop a new material capable of substantial latent heat storage capacity without major loss of physical and mechanical characteristics upon temperature increase. The scope of this research was to cover the following issues. a. Selection of the polymer blend constituents. b. Processing of polymer blends and polymer blend composites to meet targeted engineering and thermal criteria. 0. Characterization of polymer blend composites for the targeted application. ll. DEFINE 21.1 M tlieirdiainsatet chainsaielined 2.12 213 C0 ——’i CHAPTER 2 THEORETICAL BACKGROUND 2.1. DEFMTION OF TERMS 2.1.1 Arnomhous - Having no ordered arrangement. Polymers are amorphous when their chains are tangled up in any odd way. Polymers are not amorphous when their chains are lined up in ordered crystals. 2.1.2 Copoly_m_er — A polymer made from more than one kind of monomer. 2.1.3 Covalent Bond - A joining of two atoms when the two share a pair of electrons. 2.1.4 Crosslinking - Crosslinking is when individual polymer chains are linked together by covalent bonds to form one giant molecule 2.1.5 Crystal - A mass of molecules arranged in a neat and orderly fashion. In polymer crystal the chains are lined up neatly like new pencils in a package. They are also bound together tightly by secondary interactions. 2.1.6 Elastomer —- Polymers that can be stretched many times its original length without breaking, and will snap back to its original size when it is released. 2.1.7 Elongation - How long a sample is stretched when it is pulled. Elongation is usually expressed as the length after stretching divided by the original length. 2.1.8 Emulsion - A mixture in which two immiscible substances, like oil and water, stay mixed together thanks to a third substance called an emulsifier. The emulsifier is usually something like a soap, whose molecules have a water-soluble end and an organic- soluble end. The soap molecules form little balls called micelles, in which the water- sinkmdspointou tichdnheoilim mandoilsaymir tieoutsideanddem particle on the inside 2.1.12 GemDiol - A diols are unstable. "twins“.lt‘smlalndm 7.1.13 Glass transits hardandbriuielnso 1114 mm ofamatuial onede ZIJS 13g- An m 1mm balsam Emulate: ———— soluble ends point out into the water, and the organic-soluble ends point into the inside of the ball. The oil is stabilized in the water by hiding in the center of the micelle. Thus the water and oil stay mixed. A micelle with the water-soluble ends of the soap molecule on the outside, and the organic-soluble ends pointing inward, stabilizing a big brown organic particle on the inside. 2.1.9 Entropy - Disorder. Entropy is a measure of the disorder of a system. 2.1.10 First order Transition - A thermal transition that involves both a latent heat and a change in the heat capacity of the material. 2.1.11 §_e_l - A crosslinked polymer which has absorbed a large amount of solvent. Crosslinked polymers usually swell a good deal when they absorb solvents. 2.1.12 Gem Diol - A diol in which both hydroxy groups are on the same carbon. Gem diols are unstable. Why are they called gem diols? It's short for geminal, which means "twins". It's related to the word gemini. 2.1.13 Glass transition temperature - The temperature at which a polymer changes from hard and brittle to soft and pliable. 2.1.14 Heat capacity — The amount of heat it takes to raise the temperature of one gram of a material one degree Celsius. 2.1.15 Ion - An atom or molecule, which has a positive or a negative electrical charge. 2.1.16 Latent heat - The heat given off or absorbed when a material melts or freezes, or boils or condenses. For example, when ice is heated, once the temperature reaches 0°C, its temperature would not increase until it is melted. Ice has to absorb heat in order to 10 2.1.18 Modulus - usually expressed deformation For results from the 21.19 Monomer - other 11101091in of 1111 2.120 Plasticizer - A turpentine. 2.1.21 Random coil . 1mBled up in itself (1 When intennolecular ——7 melt. But even though it is absorbing heat, its temperature stays the same until all the ice has melted. The heat required to melt the ice is called the latent heat. Water will give off the same amount of latent heat during freezing. 2.1.17 Matrix - In a fiber-reinforced composite, the matrix is the material in which the fiber is embedded, (i.e., the material that the fiber reinforces). It comes from a Latin word, which means "mother". 2.1.18 Modulus - The ability of a sample of a material to resist deformation. Modulus is usually expressed as the ratio of stress exerted on the sample to the amount of deformation. For example, tensile modulus is the ratio of stress to the elongation which results from the stress. 2.1.19 Monomer - A small molecule, which may react chemically to link together with other molecules of the same type to form a large molecule, called amonomer. 2.1.20 Plasticizer - A small molecule that is added to polymer to lower its glass transition temperature. 2.1.21 Random coil - The shape of a polymer molecule when it is in solution, and it is all tangled up in itself (instead of being stretched out in a line). The random coil only forms when intermolecular forces between the polymer and the solvent are equal to forces between the solvent molecules themselves and the forces between polymer chain segments. 2.1.22 Second order transition - A thermal transition that involves a change in heat Capacity, but does not have a latent heat. The glass transition is a second order transition. 11 2123 M-l‘ha mSozinmhee 2.124 mgr-ole 2.125 Tmination - polymerization) to sit pmduotsmayreactto 2.126 cooled, and involves 2.12.8 Thermosct - thennoplastics, whicl crosslinked elastome 41.29 mm - Without failme, usual ——7 2.1.23 Strain - The amount of deformation a sample undergoes when one puts it under stress. Strain can be elongation, bending, compression, or any other type of deformation. 2.1.24 Strength — the amount of stress an object can receive before it breaks. 2.1.25 Termination - The reaction which causes the growing chain (in chain growth polymerization) to stop growing. Termination reactions are those in which none of the products may react to make a polymer grow. 2.1.26 Thermoplastic - A material that can be molded and shaped when it is heated. 2.1.27 Thermal transition - A change that takes place in a material when it is heated or cooled, and involves phenomenon, such as melting, crystallization, or glass transition. 2.1.28 Thermoset - A hard and stiff crosslinked material. Thermosets are different from thermoplastics, which become moldable when heated. Thermosets are different from crosslinked elastomers; thermosets are stiff and do not stretch the way elastomers do. 2.1.29 Toughnes — A measure of the ability of a sample to absorb mechanical energy without failure, usually defined as the area underneath a stress-strain curve. 2.2. GENERAL Synthetic polymers have considerable commercial importance and are known by several common names, such as plastics, macromolecules, and resins. From milk, air, coal and farm waste come strange chemicals, which join to make new materials. Plastics have changed our mode of thought. For generations we have been thinking of wood as wood; now, through impregnation with inexpensive chemicals, we turned wood into a new material, which can be bent, compressed turned like metal, or molded, with few of 12 A dictionary 0' or molded” Plastic m for milking his ark; 1 1°31 placed among 111 5116111: have played \- the former characteristics of wood. The age in which we now live has been termed everything from the “Electrical Age” to the “Plastic Age”. Man continues to seek out ways of doing new things, better ways of doing old things, and new ways of remaking the materials of nature. As competition in industry becomes more intense, industry depends more and more on chemistry for solution of its problems. The efforts are directed not only towards searching out new elements, but also seeking out new combinations for the elements already known. One approach, which focuses on the development of a novel polymer blend with unique combination of qualities, falls under this category. This chapter discusses important topics relating to the polymer structures, behavior and manufacture. It will also explain different polymer characteristics, which were critical to this investigation. 2.3. BASIC CONCEPTS 2.3.1 Pl_as_tig A dictionary defines “Plastic” as an adjective meaning “capable of being formed or molded.” Plastic materials, as such, are not new. Noah used a plastic material, pitch, for caulking his ark; and Moses’s mother used a similar material for daubing the little boat placed among the bulrushes.3 Natural materials such as pitch, rosin, tar, amber and shellac have played very important parts in past civilizations and are still important in our own. Additional materials were made possible by chemical combinations as time went on. To say the least, plastic is a complex material and difficult to define. There are certain facts, however, about plastics upon which all will agree: a. Plastics are synthetic. l3 b. All plaSUC binder. c. The result of being P d, .A later (if e. The final poltmenz f, The result materials- SU'UCCLIIE. Normally the molecular weight (or made 01“."4 atoms i me Mosr of the 1 molecular weights 0 Mint About linear an ”115 are more or le b. All plastics start from an initial stage, which is identified by a (synthetic) binder. c. The resinous material at a later stage must be either plastic or liquid (capable of being poured for casting). d. A later development results in a solid material by curing or drying. e. The final stage is usually reached through a rearrangement of molecules by polymerization or condensation. f. The resulting material bears little or no resemblance to the original raw materials-the process has produced a new material with a new chemical structure. 2.3.2 Polymers Normally the word polymer is used when talking about molecules whose molecular weight (or size) is in the range of several thousand or more, A linear polymer made of “A” atoms is shown in Figure 2.1. NMW—A—A—A—A—A—A—A—mwwv a linear polymer made of "A" atoms Figure 2.1. A linear polymer made of “A” atoms.4 Most of the time when we talk of polymers we are talking about molecules with molecular weights of hundreds of thousands, or even millions. We are also usually talking about linear polymers. A linear polymer is a polymer molecule in which the atoms are more or less arranged in a long chain. This chain is called the backbone. l4 Normally. some of til them. These small ch much smaller than th but the backbone cha backbone and Panda“ 11:1in The "Bl": Fit L 2.3.2.1 W . 1 Normally. it": molecules whose ate Up the backbone of '- all along the length t the backbone chain ' tarbon atom has Wt 411 do“? Pendant me full titted ~ b} a carbo' Normally, some of these atoms in the chain will have small chains of atoms attached to them. These small chains are called pendant groups. The chains of pendant groups are much smaller than the backbone chain. Pendant chains normally have just a few atoms, but the backbone chain usually has hundreds of thousands of atoms. The structure of backbone and pendant group is shown in Figure 2.2. These "A" atoms make up the backbone chain WA—fi—A—A—A—‘TL—A—WWW The "B" atoms are pendant groups Figure 2.2. Polymer structure showing pendant group.4 2.3.2.1 Polymers Repeat Units Normally, when we talk of polymers, we are not just talking about huge molecules whose atoms are arranged in chains. We like to think that the atoms that make up the backbone of a polymer chain come in a regular order, and this order repeats itself all along the length of the polymer chain. For example, in polypropylene, in Figure 2.3, the backbone chain is made up of j ust two carbon atoms repeated over and over. One carbon atom has two hydrogen atoms attached to it, and the other has one hydrogen atom and one pendant methyl group. This unit of a carbon atom with two hydrogen atoms followed by a carbon atom with a hydrogen atom and a methyl group repeats itself over 15 and met attain along the reboot structure or the re 1.7—7”— Jdod'mp’ mil-T C} C 1 To make things simple below in Figure 2.4. lite repeat unit is no repeat units in the p,- M ‘3 ‘1 ‘ ‘ \onlinear Pt P°llmers ca ltgure 2.5 and over again along the backbone chain. This little recurring structure is called the repeat structure or the repeat unit. This pattern repeats itself over and over again MMV—CHz—(ITH—CHQ— (EH—CHZ—(FH—CHT—(EH—CHZ— TH—MW CH3 CH3 CH3 CH3 CH3 Polypropylene Figure 2.3. Repeat structure of polypropylene.4 To make things simple, we usually only draw one unit of the repeat structure, as shown below in Figure 2.4. —l-CH2r—CH—l;l CH3 Figure 2.4. One unit of repeat structure.4 The repeat unit is put inside brackets, and the subscript n just stands for the number of repeat units in the polymer chain. 2.3.2.2 Nonlinear Polymer Polymers can come in other structures, though. To find out, take a look at the Figure 2.5. 16 Many poluners arranged into long line; Poltmers can be made 2.3.2.3 Branching Out Nm all pohmc chain. which is compz polymer. Some poltrr to shoun in Figure 2. Figure 2.5. A linear polymer.4 Many polymers are built so their molecules consist of many thousands of atoms arranged into long linear chains. But they don not have to be long straight chains. Polymers can be made in many other arrangements, as discussed below. 2.3.2.3 Branching Out Not all polymers are linear. Sometimes, there are chains attached to the backbone chain, which is comparable in length to the backbone chain. This is called a branched polymer. Some polymers, like polyethylene, can be made in linear or branched versions, as shown in Figure 2.6. 17 2.3.2.4 Network Molt The branch cl branch chains are an; enough branch chain polirner backbone cl llhen this happens. ' pickup in your hand rubber. such as poly .4 tire is actuall) on one molecule. too. ' 0116 molecule. The ; / Figure 2.6. A branched polymer.4 2.3.2.4 Network Molecule The branch chains have some peculiar behavior. Sometimes, both ends of the branch chains are attached to the backbone chains of separate polymer molecules. If enough branch chains are attached to two polymer molecules, it can happen that all of the polymer backbone chains in a sample will be attached to each other in a giant network! When this happens, the sample is in fact one single molecule, a molecule large enough to pick up in your hands! Polymers like this are called cross-linked polymers. Many types of rubber, such as polyisoprene and polybutadiene, are cross-linked. A tire is actually one giant network molecule, a molecule. A bowling ball contains only one molecule, too. Those old fashioned black rotary telephones, the housing is made of one molecule. The structure of a cross-linked polymer is shown in Figure 2.7. 18 #— 2325 Star Poltmers Sometimes th center. Polymers like additives in motor oi Figure 2.7. A cross linked polymer.4 2.3.2.5 Star Polymers Sometimes the ends of several polymer chains are joined together at a common center. Polymers like this are called star polymers, shown in figure 2.8.4 They are used as additives in motor oil. 19 ‘t w 3 ~ ...t.-.b Dendnmers Sometimes ti away that branches hose branches. as - Greek word for "tree Figure 2.8. A star polymer.4 2.3.2.6 Dendrimers Sometimes there is no backbone chain at all. Sometimes a polymer is built in such a way that branches just keep growing out of branches and more branches grow out of those branches, as seen in Figure 2.9. These are called dendrimers, from the ancient Greek word for "tree". 20 Dendrimers l delivery is one possi branches. It is hopec hiture. dendrimers r Figure 2.9. A structure known as dendrimer.4 Dendrimers have unusual shapes, which make really unusual properties. Drug delivery is one possibility. One silicon—based dendrimer can trap oxygen molecules in its branches. It is hoped that this can be used to make artificial blood. In the more immediate future, dendrimers might end up in coatings and as catalysts. 2.3.2.7 Molecular Structure of Polymers Let us get back to those simple linear polymers. These giant chain-like molecules, because they are so big and because of their shape, act in ways which small molecules don not. There are three ways in which polymers will act differently from small molecules: 0 Chain entanglement 0 Summation of intermolecular forces 21 o T111113 5‘ Let us define each one 2.32.7.1 Chain Most ; atoms are joined in a this chain is not stiff tangled mess. The ch molecules collective? chains nill act like s spaghetti. it slides ri; state. they act more i harder. We are more Chains are all tangle makes so many p011 cOIItposites. 2.3.2.7 2 gun. All : Wins each on. more than others. I example. water on and waters is etch is “We Water i< 0 Time scale of motion Let us define each one of the above: 2.3 2.7.1 Chain Entanglement Most polymers are linear polymers; that is, they are molecules whose atoms are joined in a long line to form a huge chain. Most of the time, but not always, this chain is not stiff and straight, but is flexible. It twists and bends around to form a tangled mess. The chains tend to twist and wrap around each other, so the polymer molecules collectively form one huge tangled system. When a polymer is molten, the chains will act like spaghetti tangled up on a plate. If you try to pull out any one stand of spaghetti, it slides right out with no problem. But when polymers are cold and in the solid state, they act more like a ball of tangled up string. Trying to pull one strand out is a little harder. We are more likely to end up making a big knot. Solid polymers are like this. The chains are all tangled up in each other and it is difficult to untangle them. This is what makes so many polymers so strong in materials like plastics, paint, elastomers, and composites. 2.3.2.7.2 Sumrngiion of Intermolecular Forces All molecules, both small ones and polymers, interact with each other, attracting each other through electrostatics. Some molecules are drawn to each other more than others. Polar molecules stick together better than nonpolar molecules. For example, water and methane have similar molecular weights. Methane's weight is sixteen and water's is eighteen. Methane is a gas at room temperature, and water is a liquid. This is because water is very polar, polar enough to stick together as a liquid, while methane is 22 very nonpolar. so it dc afiect polymers jest li compounded. The big intermolecular force. very strong in binding polymers can be very only has Van der \ya bulletproof Vests. 1‘37“ I ..3.-- “3 m This molecules do. lrnagi is to get your kids it do so uith minimal Keeping them in lir over. One way to pi when you are. \yalki his. their ability to chaotic. The chain alot slower. lfone it because he or sh or she is bonnd ll :t . ‘Lblll the dt‘Ylallc enemy-“11h me very nonpolar, so it does not stick together very well at all. So intermolecular forces affect polymers just like small molecules. But with polymers, these forces are greatly compounded. The bigger the molecule, the more molecules there are to exert an intermolecular force. Even when only weak Van der Waals forces are at play, they can be very strong in binding different polymer chains together. This is another reason why polymers can be very strong as materials. Polyethylene, for example, is very nonpolar. It only has Van der Waals forces to play with, but it is so strong it is used to make bulletproof vests. 2.3.2.7.3 Time Scale of Motion This is a fancy way of saying polymers move more slowly than small molecules do. Imagine you are a first grade teacher, and its time to go to lunch. Your task is to get your kids from the classroom to the cafeteria, without losing any of them, and to do so with minimal damage to the territory you will have to cover to get to the cafeteria.5 Keeping them in line is going to be difficult. Little kids love to run around, bouncing all over. One way to put a stop to all this chaotic motion is to make all the kids join hands when you are walking them to lunch. This would not be easy but once you get them to do this, their ability to run around is severely limited. Of course, their motion will still be chaotic. The chain of kids will curve and snake this way and that. But the motion will be a lot slower. If one kid gets a notion to just bolt off in one direction, he or she can not do it because he or she will be bogged down by the weight of all the other kids to which he or she is bound. The kid may deviate from the straight path, and make a few other kids do so, but the deviation will be far less than if the kids were not all linked together. It is the same way with molecules. A bunch of small molecules can move around a lot faster and 23 alot more chaori cally inabig long chain an 80 then how does this molecules? This slovt one, if you dissolve a the pure solvent. ln f. molecular weight. Polymers do make a polymer. a \y polymer chain. For e shows in Figure 2_1 a lot more chaotically when they are not all tied to each other. Tie the molecules together in a big long chain and they slow down, just like kids do when you join them into a chain. So then how does this make a polymeric material different from a material made of small molecules? This slow speed of motion makes polymers do some very unusual things. For one, if you dissolve a polymer in a solvent, the solution will be a lot more viscous than the pure solvent. In fact, measuring this change in viscosity is used to estimate polymer molecular weight. Polymers do not start out big. They start as small molecules called monomers. To make a polymer, a whole group of monomers is strung together in a line to form a long polymer chain. For example, styrene monomers are joined together to make polystyrene, shown in Figure 2.10. H ,H It If \ =0 : —[—C—C-]F / l H H styrene polystyrene monomer Figure 2.10. Styrene monomers joined together to make polystyrene. 2.3.3 POLYMER PROCESSES 2.3.3.1 Chemical Action A little introduction of how polymers are made is required. The chemical reaction, which makes polymers, is called polymerization. There are many of these reactions, but all polymerizations have one thing in common: they all start with small molecules, and 24 loin Them into big giant they can join in many c - - t classrfications: ‘ i ”all The Ad This sy polymerization are: 0 Addition Pol)’ o Condensation We call a polyme becomes part of the 1 part of the monomer polymer. The part th gas Let us look at St male polyethylene. lhe monomer is ad. join them into big giant molecules. We call the original small molecules monomers. But they can join in many different ways. These polymerization reactions have the following classifications:6 2.3.3.1 .1 The Addition-Condensation System This system divides polymerizations into two kinds, these two kinds of polymerization are: 0 Addition Polymerization 0 Condensation Polymerization We call a polymerization an addition polymerization if the entire monomer molecule becomes part of the polymer. We call a polymerization a condensation polymerization if part of the monomer molecule is released out when the monomer becomes part of the polymer. The part that gets released out is usually a small molecule like water, or HCl gas. Let us look at some examples to illustrate the point. When ethylene is polymerized to make polyethylene, every atom of the ethylene molecule becomes part of the polymer. The monomer is added to the polymer outright, as shown in Figure 2.1 l 25 Figure 2.11. Ethylen repeat 5‘ ln a condense the polymer. \lhen r the chlorine atoms f1 atoms. are expelled i 0 CFC‘CHg—C‘H; tb‘t‘urcn. Because rh lhe Wilmer 1\ C0 \ / I I /C:Cy _+ —H|:_(IHE H H H H Figure 2.11. Ethylene has two carbon atoms and four hydrogen atoms, and polyethylene repeat structure has two carbon atoms and four hydrogen atoms In a condensation polymerization, some atoms of the monomer don not end up in the polymer. When nylon 6,6 is made from adipoyl chloride and hexamethylene diamine, the chlorine atoms from the adipoyl chloride, each along with one of the amine hydrogen atoms, are expelled in the form of HCl gas, as seen in Figure 2.12 . O 0 H H II Cl—C—CHz-CHz—CHz—CHg—C—Cl + :N—CHz—CHz—CHz—CHTCHTCHI N: H H This Chlorine atom and this hydrogen atom don't end up in the polymer. They split off no firm HCl gas. 0 o l l I l +C—CHz—CHz—CHz—CHT—C—l‘lt-CHz-CHz-CHz-CHrCHz-CHr—ll‘l‘lr + H01 H H Figure 2.12. Condensation polymerization.6 Because there is less mass in the polymer than in original monomers, we say that the polymer is condensed with regard to monomers. The byproduct, whether it is HCl 26 gas. water. etc. is calle Addition polymerizatl ,. .a The 0t polymerization reactit 0 Chain Circuit 0 Step Groyyth The differences beryy are alittle more com acondensation polyi of the polymer one 2 Wllmenzation. nan gas, water, etc, is called a condensate. Condensation polymerizations give off byproducts. Addition polymerizations don not. 2.3.3.1.2 The Chain Growth-Step Growth System The other system of classifying polymerizations again divides polymerization reactions into two categories, and those are; 0 Chain Growth Polymerizations 0 Step Growth Polymerizations The differences between a chain growth polymerization and a step growth polymerization are a little more complicated than the differences between an addition polymerization and a condensation polymerization. In a Chain growth polymerization, monomers become part of the polymer one at a time. To Show how it works, Figure 2.13 shows a chain growth . . . . . . 6 polymerization, namely the anionic polymerization of styrene to make polystyrene. 27 Figure 3. But in step 3 shows the step go“ ethylene glycol. to hit happens is that A? + CH2: ‘1- A—CHz—E r r r r A—CHz—p': + Clip? ~+ A—sz—T—cHZ—T': r r r r H A%Hr%fl6 + CH2: a A—CHZ— $23 A chain growth polymerization: in the anionic polymerization of styrene, only styrene monomer can maetwith the growing polystyrene chain. Two growing chains won't reactnrith each other. r r r r r A—CHz—p—CHz—p—CHz—pi + A—CHz—p—CHz—p—amy Figure 2.13. Anionic polymerization of styrene to make polystyrene.6 But in step growth polymerization, things are more complicated Figure 2.14 shows the step growth polymerization of two monomers, terephthoyl chloride and ethy1€ne glycol, to make a polyester called poly (ethylene terephthalate. The first thing that happens is that the two monomers will react to form a dimer. 28 At this point in a cha would add to the din here. in the step groy of course react yyith —Cl + HO—CHg—CHz-OH Q. l _ 0... 0:0 terephthoyl chloride ethylene glycol ii ‘3 l __... c1_c@_c_o_cn dimer Figure 2.14. Step growth polymerization.6 At this point in a chain growth system, only one thing could happen: a third monomer would add to the dimer to form a trimer, then a fourth to form a tetramer, and so on. But here, in the step growth polymerization, that dimer can do a lot of different things. It can of course react with one of the monomers to form a trimer, shown in Figure 2.15. 29 Figure 11 Bmitmndoothett canbeseeninFigu Our little dimer can reactvfith a molecule of terephtoyl chloride... 0 r 0 H II II cr—c@—c—o—CH2—CH2—OH + C1—C‘.—C—Cl it ‘i’ it P I g Cl~CHC—O—CH2-CHz—O—CC— + HCl Or. . . It can react with a molecule of ethylene glycol. h’ 0. Cl —c —.—C—o—CH2-CH2-0H + HO—CHZ—CHz-OH ti fl ‘3'- HO—CHg-CHz—O—C‘C—O—CHg-CHg-OH + HCl Figure 2.15. Monomers forming trimer in step growth polymerization.6 But it can do other things, too. It may react with another dimer to form a tetramer, which can be seen in Figures 2.16 and 2.17. It may react with a trimer to form a pentamer. 3O o (xii—C Figure 2.17. Makmg‘ thin: Whigeroliglm Whom; 310%an dlinsofalllmgul worm —O 0 ll ll @C—O—CHg-CHz-OH + Cl—C‘C—O—CHyCHg-I ‘i ("3:0 M ‘i’ O 3F 0 ~57" ‘i’ 0:0 (I): ‘i O E O 5.“ Figure 2.16. Monomers forming tetramer in step growth polymerization.6 0 ll 0 o i). ii H H Cl —c ©C—0—CH1-CHz—O—C —©—c—c1 T ‘i it it 9 fl 0 l Cl —C @C—O—CHg-CHg-O -C @C—O —CH1-CH2 -0 —C‘-©—|Cl—Cl Figure 2.17. Monomers forming pentamer in step growth polymerization6 Making things more complicated, these tetramers and pentamers can react to form even bigger oligomers. And so they grow and grow until eventually the oligomers are big enough to become polymers. The main difference is this: in a step growth reaction, the growing chains may react with each other to form even longer chains. This applies to chains of all lengths. The monmomer or dimer may react in just the same way as a chain hundreds of monomer units long. But in an addition polymerization, only monomers may 31 Trying to reconcile condensation the distinctions ma distindions made I Polymerizations ca addition“ 23.4 M Glass trans will!!! (differ f" short) below u “Nahuatl: mmmlys react with growing chains. Two growing chains cannot join together the way they can in a step growth polymerization. Now it is noticed that step growth polymerization can make a polyester produce a byproduct, HCl gas. This of course will make it condensation polymerization as well as a step growth polymerization. You may have also noticed that chain growth polymerization of styrene did not produce a byproduct. This is an addition polymerization in addition to being a chain growth polymerization. It is easy to conclude here that step-growth polymerization and condensation polymerization are the same thing, and that chain grth polymerization and addition polymerization are the same thing. But this just is not true. There are addition polymerizations which are step growth polymerizations. One example is the polymerization which produces polyurethanes. There are also condensation polymerizations, which are chain growth polymerizations. Trying to reconcile the chain growth-step growth classification system and the addition- condensation classification system is really a waste of time. Each has its own criteria, and the distinctions made by one system are not always going to be the same as the distinctions made by the other. So we should not try to reconcile the two systems. Polymerizations can be step growth or chain growth, and can be condensation or addition.6 2.3.4 Glass Transition Temperature Glass transition is a phenomenon peculiar to polymers. There is a certain temperature (different for each polymer), called the glass transition temperature (or Tg for short) below which the polymer becomes hard and brittle, like glass. Some polymers are used above their glass transition temperatures, and some are used below. Hard plastics like polystyrene and poly(methyl methacrylate) are used below their glass 32 both a glass transit the amorphous por undergoes melting Whenfliel easily.So.whenu motionaheady,tu leedonthan.B duinsmuidnott Placedonthums Whitman 'I’Plyfillbemot transition temperatures; that is, in their glassy state. Their Tg's are well above room temperature, both at around 100 °C. Rubber elastomers like polyisoprene and polyisobutylene are used above their Tg's, that is, in the rubbery state where they are soft and flexible.7 2.3.4.1 Amorphous and Crystalline Polymers Glass transition is not the same thing as melting. Melting is a transition which occurs in crystalline polymers. Melting happens when polymer chains fall out of their crystal structures, and become a disordered liquid. The glass transition is a transition which happens to amorphous polymers; that is, polymers whose chains are not arranged in ordered crystals, but are just strewn around, even though they are in the solid state. But even crystalline polymers will have some amorphous portion. This portion usually makes up 40-70% of the polymer sample. This is why the same sample of a polymer can have both a glass transition temperature and a melting temperature. But we should know that the amorphous portion undergoes the glass transition only, and the crystalline portion undergoes melting only. When the temperature is warm (above Tg) polymer chains can move around easily. So, when we take a piece of the polymer and bend it, the molecules, being in motion already, have no trouble moving into new positions to relieve the stress we have placed on them. But if we try to bend sample of a polymer below its Tg, the polymer chains would not be able to move into new positions to relieve the stress, which we have placed on them. So, one of two things will happen. Either (A) the chains are strong enough to resist the force we apply, and the sample would not bend; or (B) the force you apply will be too much for the motionless polymer chains to resist, and being unable to 33 marmalade lhisolmgCin Wismllya actuallyaneffeot anallmolecules movemmidvery movearoymd chainsrmdergo ‘ mbythefime firepolymermol direction'lhe pliableisnot segmental moti segments of the cl 2342M lfvaewan meltingandclm mningcalolim suidywhathfll’l" median-81m inapolymd’Wh whenweheflif move around to relieve the stress, the polymer sample will break or shatter in our hands. This change in mobility with temperature happens because the phenomenon we call "heat" is really a form of kinetic energy; that is, the energy of objects in motion. It is actually an effect of random motion of molecules, whether they are polymer molecules or small molecules. Things are "hot" when their molecules have lots of kinetic energy and move around very fast. Things are "cold" when their molecules lack kinetic energy and move around slowly, or not at all. Now the exact temperature at which the polymer chains undergo this big change in mobility depends on the structure of the polymer. To be sure, by the time we get down to the glass transition temperature, it is already too cold for the polymer molecules, tangled up in each other as they are, to move any distance in one direction. The motion that allows a polymer above its glass transition temperature to be pliable is not usually translation motion, but what is known in the business as long-range segmental motion. While the polymer chain as a whole may not be going anywhere, segments of the chain can wiggle around.7 2.3.4.2 Measurinng If we want to know how we measure melting points and Tg's, plus latent heats of melting, and changes in heat capacity, we typically use a technique called differential scanning calorimetry (DSC). Differential scanning calorimetry is a technique we use to study what happens to polymers when they are heated. We use it to study what we call the thermal transitions of a polymer. Thermal transitions are the changes that take place in a polymer when we heat it. Melting of a crystalline polymer is one example. Glass transition is also a thermal transition. So how do we study what happens to a polymer when we heat it? The first step would be to heat it, obviously. And that is what we do in 34 invoinFigmeZ polymer pansits differential scanning calorimetry, or DSC for short. We heat our polymer in a device shown in Figure 2.18. polymer sample sample reference pan [ pan \ z )7 L_| r 1L—l—j (“1 /fl\ L ....... J computer to monitor temperature and regulate he at How Figure 2.18. DSC device to measure Tg.7 There are two pans. In one pan, the sample pan, we put our polymer sample. The other one is the reference pan. It is left empty. Each pan sits on top of a heater. Then we heat the two pans at a specific rate, usually aboutl 0 °C per minute (the same as used in the present study). The heating rate stays exactly the same throughout the experiment. But more importantly, the two separate pans, with their two separate heaters, heat at the same rate as each other. Why would not they heat at the same rate? The simple reason is that the two pans are different. One has polymer in it, and one does not. Having extra material (polymer) means that it will take more heat to keep the temperature of the sample pan increasing at the same rate as the reference pan. So the heater underneath the sample pan has to work harder than the heater underneath the reference pan. It has to put out more heat. Measuring just how much more heat it has to put out is 35 a key in a DSC experiment. Specifically, we make a plot of temperature (x-axis) vs. the difference in heat output of the two heaters (y—axis). 2.3.4.3 Heat Capacity We can learn a lot from the plot shown in Figure 2.19 below. Let us imagine we are heating a polymer. When we start heating our two pans, the computer will plot the difference in heat output of the two heaters against temperature. That is to say, we are plotting the heat absorbed by the polymer against temperature. The plot will look similar to the one shown in Figure 2.19. he at ’IL flow 9' temperature —av- Figure 2.19. Plot showing heat flow vs. temperature.7 The heat flow at a given temperature is shown in units of heat, q, supplied per unit time, t. The heating rate is temperature increase, T, per unit time, t. 36 ternperat By d heat supplie. i r The \K‘e DSC. Afte suddenly. a heat 9 _ = — = heat flow tame 1* temperature increase A T . — = heating rate time I By dividing the heat flow q/t to the heating rate T/t, we obtain the heat supplied per unit of temperature increase. q 1’ ‘I = —— = Cp = heat capacity A T A T 7 The above approach yields heat capacity using the DSC plot.7 We can learn a lot more than just a polymer's heat capacity with DSC. After a certain temperature, the DSC plot will shifts upward suddenly, as shown in Figure 2.20. 37 This increase int pOhmer ha: heat capacir Because of We can USE may he not 0\‘er a temp (lllllculL b1 glass transition temperature flow heatT -------- temperature ———+ Figure 2.20. Plot showing Tg.7 This means that we are now getting more heat flow, and thus an increase in the heat capacity of our polymer. This happens because the polymer has just gone through glass transition. Polymers have a higher heat capacity above the glass transition temperature than they do below it. Because of this change in heat capacity that occurs at the glass transition, we can use DSC to measure a polymer's glass transition temperature. It may be noticed that the change does not occur suddenly, but takes place over a temperature range. This makes picking one distinct Tg somewhat difficult, but we usually just take the middle of the range to be the Tg. 38 2.3.4.4 Crystallizatit Aboy'e the gl and squirm. and net polymer enough ene crystals. \lhen poly". heat. When this has under the sample p2 keep the temperatur flow as a big dip in Ml lhe l0 be [he Nlhlner': “who dip an 2.3.4.4 Crystallization Above the glass transition, polymers have a lot of mobility. They wiggle and squirm, and never stay in one position for very long. After right temperature polymer enough energy to move into very ordered arrangements, which we call crystals. When polymers fall into these crystalline arrangements, they give off heat. When this heat is dumped out, it makes the computer-controlled heater under the sample pan at case, because it does not have to put out much heat to keep the temperature of the sample pan rising. We can see this dr0p in the heat flow as a big dip in the plot of heat flow versus temperature, as shown in Figure 2.21. heat \ flow temperature -——-l- Figure 2.21. Drop in heat flow during DSC test8 The temperature at the lowest point of the dip is usually considered to be the polymer's crystallization temperature, or To. Also, we can measure the area of the dip, and that will tell us the latent energy of crystallization for the 39 poltrner. But mos: en'stallize. ll we a we would not get . Also. because the cnsullization an . 3.3.4.5 Melting Heat m3.“ their undoing. ll"\ mother thermal U melting temperan melt. The chains around freely. “1 melting as well a they must absorb transition. This n temperature won heater under the Dultmer in order same rate In that polymer. But most importantly, this dip tells us that the polymer can in fact crystallize. If we analyzed a 100% amorphous polymer, like atactic polystyrene, we would not get one of these dips, because such materials do not crystallize. Also, because the polymer gives off heat when it crystallizes, we call crystallization an exothermic transition. 2.3.4.5 Melting Heat may allow crystals to form in a polymer, but too much of it can be their undoing. If we keep heating our polymer past its Tc, eventually we will reach another thermal transition, one called melting. When we reach the polymer's melting temperature, or Tm, those polymer crystals begin to fall apart, that is they melt. The chains come out of their ordered arrangements, and begin to move around freely. We can spot this happening on a DSC plot. There is a latent heat of melting as well as a latent heat of crystallization. When the polymer crystals melt, they must absorb heat in order to do so. Remember melting is a first order transition. This means that when you reach the melting temperature, the polymer's temperature would not rise until all the crystals have melted. This means that the heater under the sample pan is going to have to put out a lot of heat into the polymer in order to both melt the crystals and keep the temperature rising at the same rate as that of the reference pan. This extra heat flow during melting shows up as a big peak on our DSC plot, as shown in Figure 2.22. 40 \l‘: this peak. peak to be energy to 1 transition. In i8 glass tr. reached fig [he Winn: “hill? PlOI fl 3:: ___,,/ L iTm L temperature ____;.. Figure 2.22. Heat flow during melting.8 We can measure the latent heat of melting by measuring the area of this peak. And of course, we usually take the temperature at the top of the peak to be the polymer's melting temperature, Tm. Because we have to add energy to the polymer to make it melt, we call melting an endothermic transition. In short, we see a step in the plot when the polymer is heated past its glass transition temperature. Then we see a big dip when the polymer reached its crystallization temperature. Finally, we see a big peak when the polymer reaches its melting temperature. To put them all together, a whole plot will often look something as shown in Figure 2.23. 41 The cry: polunet not sho both er abot‘e. glass 11 meltin Silher. Mm: lm‘olt ITansi Beta temperature ——!I- Figure 2.23. The DSC plot showing Tg, Tc and Tm.8 Of course, not every thing we see here will be on every DSC plot. The crystallization dip and the melting peak will only show up for polymers that can form crystals. Completely amorphous polymers would not show any crystallization, or any melting either. But polymers with both crystalline and amorphous domains will show all the features we see above. If we look at the DSC plot we can see a big difference between the glass transition and the other two thermal transitions, crystallization and melting. For the glass transition, there is no dip, and there is no peak, either. This is because there is no latent heat given off, or absorbed, by the polymer during the glass transition. Both melting and crystallization involve giving off or absorbing heat. The only thing we do see at the glass transition temperature is a change in the heat capacity of the polymer. Because there is a change in heat capacity, but there is no latent heat 42 mwmedv order tram have laten D5 much is a amorphor us. ll we answer. 7 we have per gram second time] x X lSCC-Ol' €Xperir. Simplet involved with the glass transition, we call the glass transition a second order transition. Transitions like melting and crystallization, which do have latent heats, are called first order transitions. DSC can also tell us how much of a polymer is crystalline and how much is amorphous. We know that many polymers contain both amorphous and crystalline materials. But how much of each? DSC can tell us. If we know the latent heat of melting, AHm, we can figure out the answer. The first thing we have to do is measure the area of that big peak we have for the melting of the polymer. Now our plot is a plot of heat flow per gram of material, versus temperature. Heat flow is heat given off per second, so the area of the peak is given in units of heat x temperature x time'1 x mass‘l. We usually would put this in units such as joules x Kelvin x (seconds)'1 x (grams)'l: heat X temperature J K area = . = — tame X mass 5 g We usually divide the area by the heating rate of our DSC experiment. The heating rate is in units of K/s. So the expression becomes simpler: :11: area s g J heating rate K g 43 Now we l' of the sar of the sar. melted. T crysralli; cnstalli; and we ‘ subtract Was aln T;. We induce. gh‘en ( Now we have a number in joules per gram. But because we know the mass of the sample, we can make it simpler. We just multiply this by the mass t—z—tw Now we just calculated the total heat given off when the polymer of the sample: melted. Now if we do the same calculation for the clip on DSC plot for crystallization of the polymer, we can get the total heat absorbed during crystallization. We will call the total heat given off during melting Hm, total, and we will call the heat of crystallization Hc,tota1. Now we are going to subtract the two: Hm, total - He, total = H' H' is the heat given off by that part of the polymer sample which was already in the crystalline state before we heated the polymer above the Tc. We want to know how much of the polymer was crystalline before we induced more of it to become crystalline. That is why we subtract the heat given off at crystallization. Now with H’ we can figure out the percent crystallinity. We are going to divide it by the specific heat of melting, H0...) which the amount of heat given off by a certain amount, usually one gram, of a polymer. H' is in joules, and the specific heat of melting is usually given in joules per gram, so we are going to get an answer in grams, which we will call me. 44 bElow 1h mm. we COUISE. l Sometir something in it ill? pultrner ch VOlurne. \hhen around at lowe Ofa Wilmer c some Plasticiz This is the total amount of grams of polymer that were crystalline below the Tc. Now if we divide this number by the weight of our sample, mm], we get the fraction of the sample that was crystalline, and then of course, the percent crystallinity.8 "3c = crystalline fraction “total crystalline fraction X 100 = % crystallinity Sometimes, a polymer has a Tg that is higher than we would like. We just put something in it called a plasticizer. This is a small molecule, which will get in between the polymer chains, and space them out from each other. We call this increasing the free volume. When this happens they can slide past each other more easily. They can move around at lower temperatures than they would without the plasticizer. In this way, the Tg of a polymer can be lowered to make a polymer more pliable and easier to work with some plasticizers shown in Figure 2.24.8 F; C .1“: if S OH nitrobenzene carbon disulfide B —naphthyl salicylacte Figure 2.24. Material used as plasticizers. 45 The srn inside of the ca longer be plat temperature. a 2.3.4.6 The 6] It is re: But this is an between the g crystalline p0 state. A giVer 50 the same 5 not the chain melting and ; ternDerature lemperatttre Now the 1m llhen thjs h adding heat The“ lhe tet “55 Slots b when This hear is The smell of a new car is the plasticizer evaporating from the plastic parts on the inside of the car. After many years, if enough of it evaporates, the dashboard. will no longer be plasticized. The Tg of the polymers in dashboard will rise above room temperature, and the dashboard will become brittle and crack. 2.3.4.6 The Glass Transition vs. Melting It is tempting to think of the glass transition as a kind of melting of the polymer. But this is an inaccurate way of looking at things. There are a lot of important differences between the glass transition and melting. Melting is something that happens to a crystalline polymer, while the glass transition happens only to polymers in the amorphous state. A given polymer will often have both amorphous and crystalline domains within it, so the same sample can often show a melting point and a Tg. But the chains that melt are not the chains that undergo the glass transition. There is another big difference between melting and glass transition. When you heat a crystalline polymer at a constant rate, temperature will increase at a constant rate. The amount of heat required to raise the temperature of one gram of the polymer one degree Celsius is called the heat capacity. Now the temperature will continue to increase until the polymer reaches its melting point. When this happens, the temperature will hold steady for a while, even though we are adding heat to the polymer. It will hold steady until the polymer has completely melted. Then the temperature of the polymer will begin to increase once again. The temperature rise stops because melting requires energy. All the energy we add to a crystalline polymer at its melting point goes into melting, and none of it goes into raising the temperature. This heat is called the latent heat of melting. (The word latent means hidden). Once the 46 pohrner has melt pohmer has a hi more heat with a CD’stalline polm and it undergoes is melting or he and a latent hea- amorPhOUS pol} temperature g0: 50111631ng ham no latent heat 0 does not go up increase in its 1 implies Chang called second . lhe Wilmfi 01 polymer has melted, temperature begins to rise again, but at a slower rate. The molten polymer has a higher heat capacity than the solid crystalline polymer, so it can absorb more heat with a smaller increase in temperature. Hence, two things happen when a crystalline polymer melts: it absorbs a certain amount of heat, the latent heat of melting, and it undergoes a change in heat capacity. Any change brought about by heat, whether it is melting or freezing, or boiling or condensation, which has a change in heat capacity, and a latent heat involved, is called a first order transition. But when we heat an amorphous polymer to its Tg, something different happens. First we heat it, and the temperature goes up. It goes up at a rate determined by the polymer's heat capacity. Only something happens when we reach the Tg. The temperature does not stop rising. There is no latent heat of glass transitioning. The temperature keeps going up. But the temperature does not go up at the same rate above the Tg as below it. The polymer does undergo an increase in its heat capacity when it undergoes glass transition. Because glass transition involves change in heat capacity, but it does not involve a latent heat, this transition is called second order transition. The plot in Figure 2.25 show the amount of heat added to the polymer on the y-axis and the temperature that you. would get with a given amount of heat on the x-axis. 47 heat Figure 3.25. The plo polymer. \Ve c: temperature. A is the latent he; break. The slot steepness com P101011 the rig] heat it. we dor Immature is Cam“. be t ’3“? Cushions illl‘erence bet the glass “Tin: glass melung transition temperature / temperature (”If he atI 5 heat] a-"d-f’ f ”ff ff .-""P f- 7' ___¥ T ——i- Figure 2.25. A heat vs. temperature plot for a crystalline polymer, on the left and an amorphous polymer on the right.8 The plot on the left shows what happens when we heat a 100% crystalline polymer. We can look at it and see that it is discontinuous; that is the melting temperature. At that break, a lot of heat is added without any temperature increase, which is the latent heat of melting. We see the slope getting steeper on the high side of the break. The slope of this kind of plot is equal to the heat capacity, so this increase in steepness corresponds to the increase in heat capacity above the melting point. But in the plot on the right, which shows what happens to a 100% amorphous polymer when you heat it, we don not have a break. The only change we see at the glass transition temperature is an increase in the slope, which means that we have an increase in heat capacity. We can see a heat capacity change at Tg, but no break like we do in the plot for the crystalline polymer. There is no latent heat involved in glass transition. And this is the difference between a first order transition like melting, and a second order transition like the glass transition. 48 2.3.4.7 We \he knot! Tg's. \lhat make answer relates it easily will hare one. The more e commence wigg llhat makes on that aliect the n 13.4.7.1 and the lower i Disilicones. Le Thisb ii‘ This Chair 2.3.4.7 lfigh T2 Polymer We know at this point that some polymers have high Tg's, and some have low Tg's. What makes one-polymer glass transits at 100 °C and another at 500 °C? The answer relates how easily the chains move. A polymer chain that can move around fairly easily will have a very low Tg, while one that does not move so well will have a high one. The more easily a polymer can move, the less heat it takes for the chains to commence wiggling and break out of the rigid glassy state into the soft rubbery state. What makes one polymer move more easily than another? Following are several factors that affect the mobility of a polymer chain.8 2.3.4.7.1 Backbone Flexibility The more flexible the backbone chain is, the better the polymer will move, and the lower its Tg will be. Let us look at some examples. The most dramatic one is that of silicones. Let us take a look at one called polydimethylsiloxane in Figure 2.26. CH3 +di—o—lfi he. polydimethylsiloxane Figure 2.26. Flexible backbone of polymethyl siloxane.8 This backbone is so flexible that polydimethylsiloxane has a very low Tg of -127 0C. This chain is so flexible that it is a liquid at room temperature, and it is even used to 49 thicken shampvt polytphenylene f This bar aTg. We can b will decompos. make this poly chain. Ether gr Polm bllng lhe lg . thicken shampoos and conditioners. Now we will look at another extreme, poly(phenylene sulfone), in Figure 2.27. poly(phenylene sulfone) Figure 2.27. Stiff backbone of poly (phenylene sulfone).8 This backbone of this polymer is just plain stiff. It is so rigid that it does not have a Tg. We can heat this polymer to over 5 00°C and it will still stay in the glassy state. It will decompose from all the heat before it lets itself undergo a glass transition! In order to make this polymer processable, we have to put some flexible groups in the backbone chain. Ether groups work nicely as shown in Figure 2.28. ether linkages / @::@0/ +30% 0 C Figure 2.28. Making polymer process able, ether group is added.8 Polymers like this are called poly (ether sulfones), and those flexible ether groups bring the Tg of this one down to a more manageable 190°C. 50 g) \l l.) K) J 4.) group can act as chain tries to hit each other. One adamantyl grou compound calle A big 3 molecules and dOES ll get Cal Cham too that affect: the Te pendant {1T 01]] 2.3.4.7.2 Pendant Groups Part I Pendant groups have a big effect on chain mobility. Even a small pendant group can act as a fishhook that will catch on any nearby molecule when the polymer chain tries to move. Pendant groups also catch on each other when chains try to slither by each other. One of the best pendant groups for getting a high Tg is the big bulky adamantyl group, shown in Figure 2.29. And adamantyl group is derived from a compound called adamantane. to :15 adamantane an adamantyl group attached to an R group. Fig. 2.29. Pendant group for getting high Tg. A big group like this does more than just act like hook that catches on nearby molecules and keeps the polymer from moving. It is a downright boat anchor. Not only does it get caught on nearby polymer chains, its sheer mass is such a load for its polymer chain too that it make the polymer chain move much more slowly. To see how much this affects the Tg, just take a look at two poly (ether ketones), one with an adarnantane Pendant group and one without in Figure 2.30. 51 The Tg £30111) raises it I J 'JJ _‘_> \‘ 'JJ 1lmllhow clos 01h“ lhe mot DimlCizer dOl Chaim lS to SE hitter the Tg \ , -‘l ”FUND. H o This poly(ether ketone) has a T g of 119 0C ”W Figure 2.30. Effect of pendant groups on Tg. The Tg of the polymer on the top is relatively high at 119°C, but the adamantyl group raises it even higher, to 225 °C. 2.3.4.7.3 Pendant Groups Part 11 Big bulky pendant groups can also lower the Tg. The big pendant groups limit how closely the polymer chains can pack together. The farther they are from each other, the more easily they can move around. This lowers the Tg, in the same way a plasticizer does. The fancy way to say that there is more room between the polymer chains is to say there is more free volume in the polymer. The more free volume, the lower the Tg generally. We can see this with a series of methacrylate polymers in Figure 2.31. 52 Pulpit: Figt We car longer. We sta Dob (hurt me 3.3.4.8 m3 Anton tt‘idence ot‘bt Pobtrter is at; $113 (EH3 (EH3 —l-CH2—(l3—}—n —l-CH2—(l3-l—n —l-CH2—(|:—l—n C=O C=O C=O l l l e e e CH3 (EH2 $H2 Poly(meihyl mflmryhte) CH3 (EH: 7'3 = 100' 120 ”C Poly(ethyl methacrylate) CH3 7'3 = 55 "C Polyrpmpyt methacrylate) rg = 35 or: Figure 2.31. Series of methacrylate polymers showing different Tgs. We can see a big drop each time we make that pendant alkyl chain one carbon longer. We start out at 120 ° for poly (methyl methacrylate), and by the time we get to poly (butyl methacrylate) the Tg has dropped to only 20°C, close to room temperature. 2.3.4.8 Amorphous Polymers and the Glass Transition Temperature Amorphous polymers contain no crystalline - i.e. ordered - regions, although evidence of bundled chains has been observed. A typical example of an amorphous polymer is atactic polystyrene shown in Figure 2.32. H H HH HH HlXI—IHXXHHH H HHHHHHHHHH XHXXHHxXXHX Figure 2.32. Atactic polystyrene 53 \lthen pt amorphous pol} peaks which are Figure l Amorp the glass tran brittle with a crl‘Stalllne reg “ll a diffuse mobility of th the @185 U‘ans When performing a DSC (Differential Scanning Calorimetry) test on an amorphous polymer only the glass transition temperature shows up — with no melting peaks which are associated with cystallinity (see Figure 2.33). gt "'--. fir Tg Temperature Figure 2.33. Schematic curve of typical DSC plot of an amorphous polymer Amorphous Polymers exhibit a behaviour dependent on temperature relative to the glass transition temperature. Below this temperature, the material is glassy, being brittle with a Young's modulus of the order of 1-10GPa. The stiffness is not due to crystalline regions as the glass is amorphous in nature; X-ray diffraction patterns show only a diffuse halo typical of liquids. The glassy nature is due to the reduced molecular mobility of the long chain molecules. As the temperature of the polymer is raised through the glass transition region, the modulus decreases (see Figure 2.34). 54 Tic Glass transi coefficient of e‘ indicating incre so a higher one the system and increasing muttmtttl. lt i Chemical star below . Tiexib ‘ Bulb . lucreg pm: C.) L / temperature Figure. 2.34. Effect of temperature and cross-linking on modulus. Glass transition corresponds to the onset of segmental motion in chains. The coefficient of expansion and heat capacity both increase as the temperature is increased, indicating increased molecular motion, the actual molecular volume remains constant and so a higher coefficient of expansion points to an increase in free volume associated with the system and therefore increased freedom for the molecules to move. Increasing heat capacity corresponds to an increase in heat dissipation through movement. It is a rate dependent phenomenon and is influenced by thermal history. Chemical structure heavily influences the glass transition by affecting mobility, as noted below. 0 Flexible main chain components lower Tg. - Bulky side-groups raise Tg. 0 Increasing the length of flexible side-groups lowers Tg. 0 Increasing main chain polarity increases Tg. Molecular Vt where the exces. weight increase: 3.3.4.9 Thermal The thermal as industrially p softening stage monitoring the thermally indur . Onset 0 ° The gla ' A melt with th Co'stalline Emmule. biret' with heat of fi called a Secon mshfit‘oeltat Molecular weight influences Tg significantly, especially at lower molecular weights where the excess of free volume associated with chain ends is significant. As molecular weight increases, the concentration of chain ends decreases. 2.3.4.9 Thermal Properties The thermal behaviour of polymers is unique and responsible for their attractiveness as industrially processable materials. Thermoplastics can be reversibly heated through a softening stage whereas thermosets irreversibly harden at elevated temperatures. In monitoring the heat absorption of a polymer specimen under controlled conditions, thermally induced transitions can be identified; There transitions are: . Onset of side group motion. . The glass transition, a region over which the polymer becomes rubbery o A melt temperature, exhibited only by semi-crystalline polymers, being associated with the melting of crystallites. Crystalline melting is a first—order transition characterised by discontinuities in, for example, birefringence, refractive index and heat content and specific volume associated with heat of fusion and volume change on fusion. The glass transition, however, is often called a second order transition because, although such discontinuities do not exist, there is a sharp change in heat capacity and volume expansion co-efficient. 56 “BLED Mixing between those t together are cal other. Mosr of like chicken so is insoluble in we say rnirtur: what we get it separated mat: These materia immiscible m lntmi p0lll‘lllfi‘tller plill‘glm‘ne intend, the m like the 2.4 BLENDING OF POLYMERS Mixing two polymers together can yield a material with properties somewhere between those of the two polymers mixed. Materials made from two polymers mixed together are called blends. However, it is not very often that two polymers mix with each other. Most of the time, mixing of two kinds of polymers, yields something that looks like chicken soup with two phases: a water phase and a chicken fat phase. The chicken fat is insoluble in water, so it forms little blobs in the soup separate from the water phase. So we say mixtures like chicken soup are phase-separated. Phase-separated mixtures are just what we get while trying to mix most polymers. But strangely enough, the phase- separated materials often turn out to be rather useful. We call them immiscible blends. These materials are not really blends; they cannot be if they are immiscible. Two immiscible materials are shown in Figure 2.35. —l-CH2—CH-l}l- —-[-CH2—CH=CH—CH2-lfi . polybutadiene polystyrene Fig. 2.35. Immiscible polymers.9 Immiscible blends turn out to be useful. Consider, for example, polystyrene and polybutadiene (Figure 2.35). These two polymers are immiscible. When you mix polystyrene with a small amount of polybutadiene, the two polymers would not blend; instead, the polybutadiene will separate from the polystyrene into little spherical blobs, just like the chicken fat in the soup separates from the water into little blobs. If we look at 57 the mixture unc picrure below 11 Pig The lit brittle materia polybutadiene This keeps tht instead of bre more ductile. llllClEI the llfll‘. the mixture under an electron microscope, we would see something that looks like the picture below in Figure 2.36. Polystyrene Phase ‘\ Polybutadiene Phase 0 / Fig. 2.36 The phase morphology of HIPS (high impact polystyrene) The little spheres of polybutadiene do a lot for the material. Polystyrene is a rather brittle material. It is stiff, but we can break it easily if we try to bend it. But those little polybutadiene spheres are rubbery, remember, and they can absorb energy under stress. This keeps the polystyrene from breaking. This immiscible blend has more ability to bend instead of breaking than regular polystyrene see in Figure 2.37 that is, it is tougher and more ductile. Immiscible blends of polystyrene and polybutadiene are sold commercially under the name high-impact polystyrene, or IHPS for short. 58 “\ pt Figure 3.3 Anoth. called twisted PVA Sfparate 3°] ll? tcsulr ted to make ii a l ‘ silt 13) erg 0f] —O o H —C—@—C—O—CH2—CH2—O+fi +CH2~(|3H—}fi OH poly(ethylene terephthalate) poly(vinyl alcohol) Figure 2.3 7. Immiscible blends of poly (ethylene terephthalate) and poly (vinyle alcohol). . PET PVA to Figure 2.38. Lamellae of PET and PVA.9 Another immiscible blend we are familiar with is one made from a polyester called poly(ethylene terephthalate) and poly(vinyl alcohol). In this material, PET and PVA separate into sheet like layers called lamellae, as shown in Figure 2.38 above. We call the resulting arrangement a lamellar morphology. This particular immiscible blend is used to make plastic bottles for carbonated beverages. PET makes the bottle strong, while the layers of PVA do something very important; Carbon dioxide cannot pass through 59 PVA. lithe c soda would g 2.4-.1 m The C into little spl two polymer arrangement morphology polymers. Lt polymer A a B separate it each other b pOlyrner A t 2.39. But PVA. If the carbon dioxide in our soda leaked out (it can pass easily through plain PET), soda would go flat. 2.4.1 Mg}: The difference between two immiscible blends is that in HIPS, one polymer forms into little spheres dispersed in the other. We have seen that in the PET-PVA system, the two polymers separate into layers. We call the shape made by the two phases, and the arrangement of the two phases morphology. The biggest thing one can do to affect the morphology of an immiscible blend is to control the relative amounts of the two polymers. Let us say we are trying to make an immiscible blend from two polymers, polymer A and polymer B. If we have a lot more of polymer A than polymer B, polymer B separate into little spherical globs. The spheres of polymer B will be separated from each other by a sea of polymer A, like we see in the picture below. In such a case we call polymer A the major component and polymer B the minor component, as seen in Figure 2.39. Fig. 2.39. Relative amount of polymer B in the immiscible blend.9 But if we put more polymer B into the immiscible blend, the spheres will get bigger and bigger, until they get so big that they become joined together. Now they are 60 not isolated 5 like the midd are the dorna the polymer there will he become nort like we see i polymer A i: first. Someti material. 80 bottle we tal diameter an. and] it reacl lllittk abou‘ stress in twt the domain: lltttniscible Fig. An. Wilmer SL‘ not isolated spheres anymore, but a continuous phase. The immiscible blend now looks like the middle picture above. The domains of polymer B are now joined together, but so are the domains of polymer A. When this happens, we say that the polymer A phase and the polymer B phase are co-continuous. If we keep adding more polymer B, eventually there will be so much more polymer B in the immiscible blend that polymer A will become nothing but isolated spheres surrounded by a continuous phase of polymer just like we see in the picture above on the right. Polymer B is now the major component and polymer A is the minor component, and the situation is reversed from what we had at first. Sometimes the way in which a product is processed affects the morphology of the material. Soft drink bottles are made by a technique called blow molding. To make a bottle we take a small piece of plastic that looks like a test tube, about 1 inch (2.5 cm) in diameter and maybe 6 inches (15 cm) long. We heat the tube, then inflate it like a balloon until it reaches the targeted size. This whole procedure puts the material under stress. Think about a section of the skin of the bottle. When it is being inflated, it is put under stress in two directions. This is called biaxial stress, and it causes the domains of PET and the domains of PVA to flatten out. This is how we get flat layers instead of spheres in our immiscible blend. Fig. 2.40 Processing under flow in one direction turns the spheres into rods.10 Another interesting morphology we can get is one of rod—like domains of one polymer surrounded by a continuous phase of the other see Figure 2.40. This happens 61 when the inn extrusion. W and that is st spheres of pc spheres? HO‘ immiscible l phases pith domains. spl they can. Ta they still hat The less sur and the sma each other. I POll’Shrene. Spherical dc 2.4.7 PLO} One Whmers h. separated ‘ blend to fir immiscibte about meet Winter A ——7— when the immiscible blend is put under stress in only one direction, such as during extrusion. We have to talk about one last thing when we are talking about morphology, and that is size. Let us go back to that simple case we talked about earlier, where we had spheres of polymer B surrounded by the continuous phase of polymer A. How big are the spheres? How far apart are they? Could we see them if you looked at a sample of an immiscible blend? In most cases we are not going to be able to see the two separate phases with our own eyes. In fact, it usually takes an electron microscope. So the phase domains, spherical or otherwise, are very small. But the domains do try to be as big as they can. Take our spheres for example. The bigger the spheres are, the less surface area they will have. A few bigger spheres have less surface area than a bunch of little ones. The less surface area, the better. The two polymers in an immiscible blend do not mix, and the smaller the surface area of the spheres, the less the two polymers have to touch each other. For example, on an 80:20 immiscible blend of high—density polyethylene and polystyrene, polystyrene is the minor component and thus it will form the separated spherical domains, and they tend to be in the range of 5-10 pm in diameter. 2.4.2 Properties of Immiscible Blends One unusual property of immiscible blends is that one made from two amorphous polymers has two glass transition temperatures. Since the two components are phase separated, they retain their separate Tgs. In fact, scientists often measure the Tg of a blend to find out if it is miscible or immiscible. If two Tgs are found, then the blend is immiscible. If only one Tg is observed, then the blend is likely to be miscible. But what about mechanical properties? Let us consider an immiscible blend of a major component polymer A and a minor component polymer B, whose morphology is that of spheres of 62 polnner B d? immiscible t phase is absr the immiscil make irnrnis some tricks flow. lf we ] rods instead They make ' Ano the two pol: different m are present both phases But one of C0Inpatihih' more tightl Other. But : hate to be polymer B dispersed in a matrix of polymer A. The mechanical properties of this immiscible blend are going to depend on those of polymer A, because the polymer A phase is absorbing all the stress and energy when the material is under load. In addition, the immiscible blend is going to be weaker than a sample of pure polymer A. So why make immiscible blends then, if separate materials are stronger? It turns out that there are some tricks one can do to make immiscible blends strong. One is to process them under flow. If we process them under flow in one direction, the minor component will form rods instead of spheres, these rods act like the fibers of a reinforced composite material. They make the material stronger in the direction of the rods.10 Another way to make a strong immiscible blend is to use more equal amounts of the two polymers. When the relative amounts of the two polymers are equal, we get a different morphology than when one is in large excess. When polymer A and polymer B are present in roughly equal amounts, they form two co-continuous phases. This means both phases will be bearing the load of any stress on the material, so it will be stronger. But one of the most interesting ways to make immiscible blends stronger is to use a compatibilizer. A compatibilizer is anything that helps bond the two phases to each other more tightly. In an immiscible blend, the two phases are not bonded very strongly to each other. But if stress and energy are going to be transferred between the components, they have to be bound to each other in some fashion, as shown in Figure 2.41 and 2.42. A Block B Block Figure 2.41. Bonding of different blocks together. 63 Figure 2 Often immiscible bi poljmer B ag Component 2 011421th is Segment MP The . $ng 10 W31 lhe Phase be then be $th The block c. him One Pl mechanical Copl‘llmers Mlmme l VA Polymer 8 Phase Polymer A phase A Figure 2.42. Phase boundary being shown between two immiscible materials.10 Often times a compatibilizer is a block copolymer of the two components of the immiscible blend. Let us take our example of an immiscible blend of polymer A and polymer B again. Let us make polymer A the major component and polymer B the minor component, and then let us throw in a block copolymer of A and B. A block copolymer of A and B is a polymer with one long segment of polymer A joined to another long segment of polymer B. The A block is going to want to be in the polymer A phase, and the B block is going to want to be in the polymer B phase. So the copolymer molecule has to sit right on the phase boundary between the polymer A and the polymer B phases. The A block can then be sitting in the polymer A phase, and the B block can stay in the polymer B phase. The block copolymers tie the two phases together, and allow energy to be transferred from one phase to the other. This means that the minor component can improve the mechanical properties of the major component rather than worsen them. Graft copolymers are also used as compatibilizers. HIPS contain graft copolymers of polystyrene grafted onto a polybutadiene backbone chain. These graft copolymers allow 64 stress to be tra polybutadiene poly-styrene pl in Figure 2.43 Comp about the size Spheres. the r than lots and fluface area i 5llheres still ‘ Phase bound C0Ullhtihiliz. great. 50 \th mimiSt‘ihle t \tfle‘ abom ; mp0llTlter t. MmlTeIte stress to be transferred from the polystyrene phase to the polybutadiene phase. Since polybutadiene is rubbery, it dissipates the energy, which would otherwise cause the brittle polystyrene phase to break. This is why HIPS is tougher than regular polystyrene, shown in Figure 2.43. Polystyrene grafted chains x \L‘R Polybutadiene backbone / Figure,2.43. Material grafted to backbone. H Compatibilizers also have another effect on immiscible blends. We talked earlier about the size of spheres of the minor component in an immiscible blend. The bigger the spheres, the more stable they are, because a few larger spheres will have less surface area than lots and lots of small ones. The two polymers have minimum contact area. The less surface area the spheres have, the less contact the two phases have. This means the spheres will tend to be relatively large. But a compatibilizer lowers the energy of the phase boundary, the two phases can thus stand each other a little more when there is a compatibilizer present. So the need to minimize contact between the two phases is not as great. So when a compatibilizer is used, our spheres do not need to be as big. In our 80:20 immiscible blend of high-density polyethylene and polystyrene, the polystyrene spheres were about 5-10 pm in diameter. When enough of a polystyrene-polyethylene block copolymer (enough being 9%) is added to the immiscible blend, the size of the polystyrene spheres drops to about 1 nm1 1. 65 This the spheres. greater the a from one ph 3.4.3 M Blen the same so gone away; are miscible mmet hundreds or mention the So i we are aboi together. T] \till have a 1.4.4 y:r9 ln SOmeyrheR- WISltjon I 0“ lbs“ ran. — This is good for the mechanical properties of the immiscible blend. The smaller the spheres, the greater the area of the phase boundary between the two phases. The greater the area of the phase boundary, the more efficiently energy can be transferred from one phase to the other, meaning better mechanical properties. 2.4.3 Making Blends Blends are usually made in two ways. The first way is to dissolve two polymers in the same solvent, and then wait for the solvent to evaporate. When the solvent has all gone away, we will be left with a blend at the bottom of beaker, presuming two polymers are miscible. While this method works fine in the laboratory, it could get expensive if we tried to do this industrially. Solvents are not cheap, and if we are going to evaporate hundreds or thousands of gallons of them, we will be paying a lot of money. Not to mention the effects on the environment of putting so much of toxic solvents into the air. So for making blends in large amounts, we heat the two polymers together until we are above the glass transition temperatures of both polymers, and we mix them together. This is often done in machines such as extruders. When the material cools, we will have a nice blend, again, presuming our two polymers are miscible. 2.4.4 Properties of Blends In general, a miscible blend of two polymers is going to have properties somewhere between those of the two unblended polymers. Take, for example, the glass transition temperature. If we take polymer A and blend it with polymer B, Tg will depend on the ratio of polymer A to polymer B in the blend. We can see this in the graph below (Figure 2.44).“ 66 ll poly increne as th generally line the two polyr. hifiller than e: mobility; '3‘ PM: ii In In .+—_ T of T S polymer A ‘— % polymer B Figure 2.44. Linear relationship of Tg versus blend Proportion.” If polymer B has a higher Tg than polymer A, the Tg of the blend is going to increase as the relative amount of polymer B in the blend increases. The increase is generally linear, as shown in the graph. But the plot is not perfectly linear. Sometimes if the two polymers bind more strongly to each other than to themselves, the Tg will be higher than expected (see Figure 2.45a), because the stronger binding lowers chain mobility. T of «It—— T of 3' *— 8 1’ g g] / polymer B g1 / polymer B Tg of ‘4" Tg 0f ‘4 polymer A p olymer A .____.___..__p ___—.__)n. % polymer B % polymer B (a) (b) Figure 2.45. Non-linear relationship of Tg versus blend proportions]l In most cases, the two polymers bind less strongly with each other than with themselves, so the Tgs of the blends are usually a little lower than expected (Figure 67 2.45b). We 1 for Other prc they all gene each polyune varying the : This can be PPO is a re: process; it i: them above only hard hr and polrsrs the l, of 1h. 3- ;.5 TH] ‘— 11 is liquid. and molecules t cthleris' Solid Slate f SubSlahce. lhtrmodyn Unilhrm 1h from Other Slocum ( 2.45b). We have been talking about Tg until now, but what holds for Tg generally holds for other properties. Mechanical properties, resistance to chemicals, radiation, or heat; they all generally plot the same way as Tg does with respect to the relative amounts of each polymer in the blend. This makes altering the properties of a blend fairly simple. By varying the relative amounts of the two polymers, we vary the properties of the blend. This can be very useful. Let us see the example of poly (phenylene oxide), a.k.a. PPO. PPO is a very heat resistant polymer. But it has some drawbacks. It is very hard to process; it is too heat resistant. Amorphous polymers are usually processed by heating them above their Tg. But with a Tg of 210°C, heating PPO enough to make it soft is not only hard but also expensive. With polystyrene and PPO blending nicely with each other, and polystyrene having a Tg of only about 100°C, blending polystyrene with PPO drops the Tg of the blend, which makes the blend much more processable than straight PPO. 2.5 THE CONCEPT OF PHYSICAL STATES OF POLYMERS It is well known that a substance can exist in three states of aggregation: gas, liquid, and solid. The aggregate states are determined by the nature of thermal motion of molecules or atoms that make up a substance. The most intensive thermal motion is characteristic of the gaseous state, and the least intensive of the solid state. As a rule, the solid state is also characterized by the closest packing of atoms and molecules in a substance. The liquid state is intermediate between the gaseous and the solid state. The thermodynamic definition of the phase is as follows. A phase is a part of a system, uniform throughout in chemical composition and physical properties, which is separated from other homogeneous parts of the system by boundary surfaces. There also exist a structural definition of a phase based on the difference in the degree of order in the 68 arrangement dimensional substance. I phase state i dimensional there is shor molecule. E amorphous polymer bef criteria forr m'SIAlline ] fact in the 5 solid state j follows the Characteriz mile Physi and the gla Olintensiy lseintents H1051 liqui. all“? to t' bl \isc. osi A —7— arrangement of atoms or molecules. The crystalline phase is characterized by three- dimensional long—range order in the arrangement of atoms or molecules that make up a , substance. Liquids are in a phase state, which is typically devoid of a crystal lattice. This phase state is usually called the amorphous state. In the liquid phase there is no three dimensional long range order in the arrangement of molecules (or part of molecules), but there is short range order usually extending over not more than 10-15 A from any chosen molecule. Evidently, these concepts are not sufficient for the description of the state of an amorphous polymer in the glassy state, say, atacticpolystyrene at room temperature, this polymer being a typical amorphous polymer. On the one hand, such a polymer meets the criteria formulated for the solid state of matter, but it can by no means be classified as a crystalline phase. Hence, while being a liquid by its physical state, such a polymer is in fact in the solid state of aggregation. Thus, state of this polymer may be classified as a solid state in which there is no three dimensional long-range order. From the foregoing it follows that such conceptions as phase and physical states are insufficient for the characterization of polymers. In this connection there has been introduced the concept of three physical states in which polymers can exist: the visco—fluid state, the rubbery state and the glassy state. The visco-fluid state of polymers is characterized by the possibility of intensive thermal motion of individual units, large fragments of the polymeric chain (segments), and movement of the macromolecules as a whole. This state is typical of most liquids. The most important specific feature of polymers existing in this state is the ability to flow under the influence of the applied stress (fluidity). Fluidity is characterized by viscosity, which as a physical phenomenon belongs to the class of transport processes; it is relaxation by its nature. When the temperature is lowered, a liquid can crystallize or 69 pass to the 212 transition to tl polymers. ln t lhe glassy stz and also atorr ribrations. L( temperature i pass. as a ml: The r mbhety' State motion. but t Polymers in Capable of u seem] hum flexible long their on ging IEmll‘ffalure glam State ‘ . .n ME Al idllt‘tile'fl y‘ htlou. pass to the glassy state, which sets in when highly viscous liquids are overcooled. The transition to the glassy state is possible for both low molecular mass substances and polymers. In this state polymers are no longer capable of undergoing segmental motion. The glassy state is characterized by the vibrational motion; small units in the main chain and also atomic groups, which make up side pendant groups, can execute torsional vibrations. Low molecular mass liquids can pass directly to the glassy state when temperature is lowered. However, polymers that have sufficiently high molecular masses pass, as a rule, from the visco—fluid state first to the rubbery state. The rubbery (highly elastic) state is characteristic of polymers only. In the rubbery state, individual units, atomic groups and segments undergo intensive thermal motion, but the movement of macromolecules as separate kinetic units is impossible. Polymers in the rubbery state possess remarkable mechanical properties. They are capable of undergoing enormous recoverable deformations, which sometimes amount to several hundred percent. The essence of this phenomenon consists in that the folded flexible long chains straighten out under the influence of the applied stress and return to their original shape after the stress is removed, as a result of thermal motion, the high temperature limit is the glass transition temperature Tg (below which the polymer is in the glassy state)” 2.6 MECHANICAL PROPERTIES OF POLYMER COMPOSITES A lot is talked about polymers as being "strong" and "tough" or maybe even "ductile". Strength, toughness, and ductility are all mechanical properties, as discussed below. 70 3.6.l m Streng might not knt polymers. Fir polymer has 1 Figure 2.46. Tens subjected ter A polymer 5 Compress it. Cor. that has to 1 is 3130 fleX‘ “Us dies to 2.6.1 _S_t_ngt_h Strength is a mechanical property that we should be able to relate to, but you might not know exactly what we mean by the word "strong" when we are talking about polymers. First, there is more than one kind of strength. There is tensile strength. A polymer has high tensile strength if it is strong when one pulls on it like the one shown in Figure 2.46. 1=+—-——+e Fig. 2.46. Tensile strength of the specimen.12 Tensile strength is important for a material that is going to be stretched or subjected tension. Fibers need good tensile strength. Then there is compression strength. A polymer sample has a high compressive strength if it is strong when one tries to compress it, as shown in Figure 2.47. .__.-.__. Figure 2.47. Compression strength of specimen. 12 Concrete is an example of a material with good compressive strength. Anything that has to support weight from underneath has to have good compressive strength. There is also flexural strength. A polymer sample has high flexural strength if it is strong when one tries to bend it, as shown in Figure 2.48. i— t t Figure 2.48. Test for flexural strength of the specimen.12 71 There strength if it i: has high irnpa hammer. 2.6.2 Elong —* There knoyting hov something. It trying to hrez sample. Elor that anything sample been We talk ahot stretched ('L lllll. l’lti the afllount slungafim be 3N6 to g ‘0010 100 There are other kinds of strength we could talk about. A sample has a high torsion strength if it is strong when one tries to twist it. Then there is impact strength. A sample has high impact strength if it is strong when one hits it sharply and suddenly, as with a hammer. 2.6.2 Elongation There is more to understanding a polymer's mechanical prOperties than merely knowing how strong it is. All strength tells us is how much stress is needed to break something. It does not tell us anything about what happens to our sample while we are trying to break it. That is where it pays to study the elongation behavior of a polymer sample. Elongation is a type of deformation. Deformation is simply a change in shape that anything undergoes under stress. When we are talking about tensile stress, the sample become deforms by stretching, becoming longer. We call this elongation. Usually we talk about percent elongation, which is just the length the polymer sample is, after it is stretched (L), divided by the original length of the sample (Lo), and then multiplied by 100. L —— X 100 = % elongation Lo Ultimate elongation is important for any kind of material. It is nothing more than the amount we can stretch the sample before it breaks. Elastic elongation is the percent elongation we can reach without permanently deforming our sample. Elastomers have to be able to stretch a long distance and still bounce back. Most of them can stretch from 500 to 1000 % elongation and return to their original lengths without any trouble. 1‘2 72 3.6.3. M Elasto materials. like we want to in modulus. To Strength and material. just the amount c stress leyel. versus elong eftk‘s‘ially —i—f 26.3 Modifies Elastomers need to show high elastic elongation. But for some other types of materials, like plastics, it is usually better that they do not stretch or deform so easily. If we want to know how well a material resists deformation, we measure something called modulus. To measure tensile modulus, we do the same thing as we did to measure strength and ultimate elongation. This time we measure the stress we are exerting on the material, just like we did when we were measuring tensile strength. We slowly increase the amount of stress, and then we measure the elongation the sample undergoes at each stress level. We keep doing this until the sample breaks. Then we make a plot of stress versus elongation, as shown in Figure 2.49.12 tenslrlle stress-strain mod us curve / : ll stress -' tensile strength it "—_"' . strain (elongauon) Figure 2.49. Stress elongation curve.12 There are times when the stress-strain curve is not linear; for some polymers, especially flexible plastics, we get curves that look like the one shown in Figure 2.50.12 73 The s charging oi as can be SCI moduli. and heureen fib bl elongatie 3.6.4 m Tha iofonnatior hone 2.51 OIlhe ener initial modulus stress _—__+ stram Figure 2.50. Stress strain curve12 The slope is not constant as stress increases. The slope, that is the modulus, is changing with stress. In a case like this we usually take the initial slope as the modulus, as can be seen in the stress-strain curve above. In general, fibers have the highest tensile moduli, and elastomers have the lowest, and plastics have tensile moduli somewhere in between fibers and elastomers. Modulus is measured by calculating stress and dividing by elongation, and would be measured in units of stress divided by units of elongation. 2.6.4 Toughness That plot of stress versus strain can give us another very valuable piece of information. If one measures the area underneath the stress-strain curve (the hatched area Figure 2.51)”, the result is occasionally called toughness. Toughness is really a measure of the energy a sample can absorb before it breaks. 74 How is answer is that s tells how much lhe Practical di Strong, it is not to show this. I and 0116 crosse stress-strain stress toughness strain Figure 2.51. Area under curve is showing the toughness. 12 How is toughness different from strength? From a physics point of view, the answer is that strength tells how much force is needed to break a sample, and toughness tells how much energy is needed to break a sample. But that does not really tell us what the practical differences are. What is important in knowing that just because a material is strong, it is not necessarily going to be tough as well. We will look at some more graphs to show this. Take a look at the one below, the one with three plots, one dotted, one solid, and one crossed. Strong, not tough Strong and tough stress not strong, not tough ____——h- stram Figure 2.52. Comparison of Toughness.12 75 The done As can be seen. is n01 much are: before it breaks. it breaks is call: sample that is b dotted pl ot. but sample's curve. can the solid sa two. The solid Deformation al would not be d materials to be not bend or bi: llllileitngoc dEfOImafiom i bending Stretr all the better. llule bit of so POLY Mlxln milk“ for a. The dotted plot is the stress-strain curve for a sample that is strong, but not tough. As can be seen, it takes a lot of force to break this sample, but not much energy, as there is not much area underneath the curve. Likewise, this sample ca not stretch very far before it breaks. A material like this, which is strong, but ca not deform very much before it breaks is called brittle. On the other hand, the solid plot is a stress-strain curve for a sample that is both strong and tough. This material is not as strong as the sample in the dotted plot, but the area underneath its curve is a lot larger than the area under the dotted sample's curve. So it can absorb a lot more energy than the dotted sample can. So why can the solid sample absorb so much more energy than the dotted plot? Take a look at the two. The solid sample elongates a lot more before breaking than the dotted sample does. Deformation allows a sample to dissipate energy. If a sample ca not deform, the energy would not be dissipated, and will cause the sample to break. In real life, we usually want materials to be tough and strong. Ideally, it would be nice to have a material that would not bend or break. The dotted sample has a much higher modulus than the solid sample. While it is good for materials in a lot of applications to have high moduli and resist deformation, in the real world it is a lot better for a material to bend than to break, and if bending, stretching or deforming in some other way prevents the material from breaking, all the better. So when we design new polymers, or new composites, we often sacrifice a little bit of strength in order to make the material tougher. '2 2-7 WW Mixing of two or more polymers for producing blends or alloys is a versatile strategy for achieving a specified portfolio of physical properties. The rheology of POlymer blends is complex, and the manner in which two (or more) polymers are 76 compounded tot?f phase morpholog range of blend rn characterisncs. C gite alloys pith 3.7.1 Co_rnpo_ur The key ; ttitb one constin discussion of ble slovt defonnatio Experiments to t Changes defined the (iron deform Elbert strain rate break Point oecr stabilizing gmfa into morphologj Malachi tensi. compounded together is of vital importance in controlling the microstructure (particularly phase morphology) and thus the properties of blends. Processing can provide a wide range of blend microstructure; this provides many possibilities for tailoring the blend characteristics. Compatibilisation, that is modification of normally immiscible blends to give alloys with improved qualities, is another powerful tool in polymer blending. '3 2.7.1 Compounding Of Polvmer Blends. The key goal of polymer blend compounding is to produce a refined morphology, with one constituent finely dispersed within the other. A natural place to start a discussion of blend technology is with liquid emulsions. In 1934, Taylor14 modeled the slow deformation and rupture of suspended drops in a dilute emulsion and conducted experiments to prove his theory. By balancing viscous forces with surface tension Changes defined by curvature of the suspended drop. Taylor developed an expression for the drop deformation (Figure 2.53) In addition, he defined a limiting droplet size for a given strain rate when viscosity and surface tension of the fluid phases are known. The break point occurs when the Viscous forces action on the drop surface overwhelm the Stabilizing surface tension. This pioneering work was followed by several investigations into morphology formation as a function of the balance of fluid stresses for balancing interfacial tension. 15’16’1 7 77 Dit'erse for example. Fig and operating or performance. It condition fora < a. Sine feed b. Higl care SOllt‘ C- Corr imp] Figure 2.53. Deformation of Dilute Droplets in a shear Fieldl4 Diverse mixer and extruder types are used in polymer blend compounding (see, for example, Figure 2.54).15 Rotor configuration, feed sequencing, temperature policy, and operating conditions are factors that can be adjusted for optimal compounder performance. Fundamental dispersion studies can hardly predict the right geometry and condition for a commercial compounding process, but they do identify rules, for example: a. Since dispersion is a phase reduction process, it pays to generate a well—mixed feed in the feeder train or feed section of the compounder. b. High stresses applied during melting are important and friction dependent, and care should be taken to reserve lubricating fluids, powders and low melting solids for post addition. 0. Compatibilizers reduce the interfacial tension and result in dramatically improved dispersions. 78 COl‘lt dilu f. Sus deft The e] Ieehque ant resulting pol} “mun-def stabilizing in during PlHStit Fe Stretching flows are more effective than shearing flows for phase rupture. e. Elastic melts resist deformation and may have to be compounded as concentrated suspensions at the co-continuous composition and subsequently dilute with matrix phase for adequate dispersion. f. Sustained deformation does not result in sustained phase dispersion. Rapid deformation changes cause more effective dispersion. b. Rotor Mister a. Ribbon Mixer Figure 2.54. Examples of Mixers and Extruders used in Polymer Blend Compounding.15 The choice of compounder, operating condition (rate, rpm, temperature), feeding technique and compounder configuration all influence the quality and texture of the resulting polymer blend. The dispersiOn mechanism is driven by the capability of a compounder to generate a stress history of sufficient peak magnitude to disrupt the stabilizing interfacial forces of the blend and by the complicated deformations generated during plastication. The melt mixing dispersion process is controlled by the shear viscosity and elasticity ratios of the components and the deformation field generated by 79 the operating or nonoptirnal fats degrade the dis 2.7.2 Cornpa In somt brittle: while t rule. the ultim; dispersed phas interfaces. aris such polnners chemical was The cc possesses a or addition of a t 00nstituemg (; POllmerblent —-————7 the operating condition and mixer geometry. Clearly, a blend can be mixed in a nonoptimal fashion whereby agglomeration flow fields and thermodynamic coalescence degrade the dispersion. 2.7.2 Compatibilisation of Polymer Blends In some cases melt mixing two polymers results in blends which are weak and brittle; while the low deformation modulus may follow an approximately linear mixing rule, the ultimate properties certainly will not. This is because the incorporation of a dispersed phase in a matrix leads to the presence of stress concentrations and weak interfaces, arising from poor mechanical coupling between phases. Compatibilisation of such polymers may be achieved by the addition of a third component, or by in situ chemical reaction tailoring of the phase structure, and hence properties. 16 The constituents of a polymer blend are called compatible here if the blend possesses a commercially desirable set of properties. Compatibilisation, either by the addition of a third component or by inducing in situ chemical reaction between blend constituents (i.e., reactive blending), can play an important role in the development of polymer blends. The factors contributing to end use properties of polymer blends are illustrated in Figure 2.55, these factors relate to melt compounding and subsequent conversion processing to produce finished articles. The mechanical properties of polymer blend will be determined not only by the preperties of its constituents, but also by the phase morphology and the interface adhesion, both of which are important from the vieWpoint of stress transfer within the blend in its end use application. The phase morphology will normally be determined by the processing history to which the blend has been subjected, 8O in which such fat the theology oft melt are irnpona equilibrium. but other: this usual or both phases. . occasionally by in any c in complex way reduce the inter extremely fine adhesion at phz stabilize the di; Phase-bounday extent \ti‘th ad. tsuch as ntodit C 0111p: one of the toll 3- Ac C. A, in which such factors as the process (mixer type, rate of mixing and temperature history), the rheology of the blend constituents and the interfacial tension between phases in the melt are important. The phase morphology is unlikely to be in thermodynamic equilibrium, but generally will have been stabilized against de-mixing by some method or other; this usually means via quenching to below the glass transition temperature of one or both phases, or via the occurrence of crystallinity in one or both phases, or occasionally by cross-linking. In any case, it is readily understood that compaibilisation can in principle interact in complex ways to influence final blend properties. One effect of compatibilisers is to reduce the interfacial tension in the melt, causing an emulsifying effect and leading to an extremely fine dispersion of one phase in another. Another major effect is to increase the adhesion at phase boundaries, giving improved stress transfer. A third effect is to stabilize the dispersed phase against growth during annealing, again by modifying the phase-boundary interface, in practice, it is likely that all these effects will occur to some extent with addition of a particular compatibiliser, and that the possibility of other effects (such as modification of rheology) may also occur. Compatibilisation of the constituents in polymer blend can be accomplished using one of the following methods. ”"8 a. Achievement of thermodynamic miscibility. b. Addition of block and graft c0polymers. e. Addition of functional/reactive polymers. 81 dine There i the requiremer Prnc rate, d. In situ grafting/polymerization (reactive blending). There is some overlap between these approaches, and which to use will depend on the requirements of the situation. Process [T ype, Rheology of lnterfacial tension rate. temperature] Components tn melt Stabilisation Component - » mechanical Phase M orphology lnterfacral Adhesion properties Mechanical properties Figure 2.55. Factors Contributing To End Use Properties In Melt Compounded Blends, Highlighting The Role Of Compatibilities 2.7.3 Theoretical Modeling of Polymer Blend Behavior Mechanical properties of polymer blends are influenced by their degree of homogeneity. As blends depart from the ideal molecular or super-molecular homogeneity, and the dimensions of the regions of in-homogeneity increase, they approach a composite material in which the phases, now of dimensions of 0.01 pm or more, have clearly different properties. We can then use the terminology of modern composite materials to describe them. In such materials, two parameters must be defined: 82 ( 1 l the shapes further define : lie between 0.1 A poly phases are an- randomized. I micro-crystals and spherical] are non-spherl isotropic the c' in artisotr0py - schematic dia (1) the shapes of the in homogeneities; and (2) their degree of orientation. We may further define a micro-composite as a composite in which the dimensions of the phases lie between 0.01 pm, and a macro-composite as having dimensions greater than lum. A polymer blend may have isotropic mechanical (and other) pr0perties even if its phases are an—isotropic provided that over a sufficiently small volume the anisotropy is randomized. Thus if the phases are highly oriented crystallites, a random orientation of micro-crystals will result in an isotropic assembly. Of course, if the phases are isotropic and spherically symmetrical, this will also ensure overall isotropy. However, if the phases are non-spherical (elliptical, fibrous or lamellar), then even if they are themselves isotropic the differences in elastic (or visco-elastic) properties between phases will result in anisotropy on the global scale unless the geometrical differences are randomized. The schematic diagrams of such assemblages are shown in Figure 2.56 {)0 Quasi Homogenous (:9 tilt Fibrous Figure 2.56. Schematic structural elements in polymer blends. 83 The eas elastic properti effect still be r example. 30% modulus EB. vt Althor properties sue simple rule in to many .As sc separate phast Itnpro materials of e 2.57a). If the? strains in eac mamas : lake Corsican“, The easiest way to model the polymer blend behavior, if little is known about the elastic properties of the phases or of their geometry or orientation, is to assume that their effect will be roughly proportional to their volume fraction in the mixture. Thus, for example, 30% of polymer A with modulus EA, blended with 70% of polymer B with modulus 133, will result in a modulus: E=0.3 EA+ 0.7 EB Although this has been written for Young’s modulus it will also apply for other properties such as shear modulus and specific heat which as much justification. This simple rule must always be treated with great caution. The reasons for its inaccuracy are many”. As soon as better information is available to the nature and properties of the separate phases, much better decision can be made. Improvements on the ‘rule of mixture’ law were introduced in 196320. Given two materials of elastic moduli E1 and E2, they may be arranged in parallel or in series (Figure 2.57a). If their concentrations are C1 and C2 respectively, then by considering equal Strains in each it is easy to Show that the combined modulus follows the ‘rule of mixtures ’ : EC 2 C1 E1 + C2132 If, however, they are arranged in series (Figure 2.57b), then they carry equal stress and we find: l/Ec = Cr/Er + Cz/Ez Takayanagi20 proposed series-parallel models like those in Figure 2.58, by considering the combinations separately we find: 84 And In mode proportions C 1. parallel mixture polymer 1 and z diyisions into b would hare to l assumption nta ineach block a state of strain 1 related by up it POltmer blend in each phase - Paisson‘s ratit not exact. E... = [h/(C1E1+C2E2) = (l-h)/E2]'l And Ecb = Cl [h/E1+(1-h)/E2]“ + C2E2 In model ‘a’ (Figure 2.58a), parallel arrangement of polymers 1 and 2 in the proportions C1, C2 is in series with a quantity l—h of polymer 2, the proportions of the parallel mixture being ‘h’. In model ‘b’ (Figure 2.58b), a parallel arrangement of pure polymer 1 and a series mixture of l and 2 are used. It is tempting to think of these divisions into blocks as real but this should be avoided since important assumptions would have to be made which are not physically realistic. In the first place the assumption made in the Takayanagi20 scheme is that the stresses and strains are uniform in each block and second, that they are of one from only (usually tensile). In a general state of strain in a body there are six components of strain and six of stress, and these are related by up to 21 elastic coefficients. Even in the simplest case, where the phases of the polymer blend are isotropic (which is not a practical case), we have two elastic constants in each phase to consider. Tensile strain will cause lateral contraction according to Poisson’s ratio and so, in general, the simple picture given by the Takayanagi20 models is 1101’ exact. 85 n.0, E202 (a) 13th (b) Figure 2.57. The Takayanagi Models; (a) Parallel: (b) Serieszo. 86 Ct T C2 E1 E2 h [at E2 l-h Eca Ct T C2 [bl l-h E2 3‘ Ecb Figure. 2.58. The Takayanagi Series-Parallel Models20 87 3.1. SELECTIOT 3.1.1. olyrners Two can of thermal energ thermoplastics. absorption capa resistance of lht a. Inte b. Cat Polj Alc' Du Ch Ha 0- Co The se room limpet: directly 3,, a\‘ailability; t ”lanltfacmre. CHAPTER 3 SPECIMENS MATERIALS AND FABRICATION 3.1. SELECTION OF MATERIAL 3.1.1. Polymers Two categories of polymers were searched: (1) those with low melt temperatures of thermal energy absorption near room temperature; and (2) the high melt temperature thermoplastics. Our goal is to blend these two in order to complement the thermal energy absorption capacity of the first group with the mechanical properties and temperature resistance of the second group. We searched the following sources: a. Internet Resources. b. Catalogs issued by different producers like Aldrich Chemical Co., General Polymers & Co., AD Tech Plastics, SP Scientific Polymer Products, Inc., Aldon Corp., Hubber, J. M. Corp Engineer Materials, Alcon Chemicals, Dupont Chemicals, AOC-Quality Resins, Sigma Chemical Catalog,GF S Chemicals Product Catalog, Brandrup, J. and Immergut, H., “polymer Handbook,” john Wiley & Sons, 1997. 0. Contacts with manufacturers. The search started with the selection of polymers with melt temperature near room temperature. An exhaustive search was conducted to make a preliminary selection of readily available polymers, noting that the lack of existing applications limits availability. Table 3.1 presents the readily available materials, which were obtained from manufactures. A symbol was assigned to each material for convenience. Initial screening 88 of these material discarded if it u‘ order to assess t' thermoplastics. of these materials was done based on physical state at room temperature; the material was discarded if it was liquid or melt at room temperatures. DSC tests were also performed in order to assess the latent heat and transition temperature of selected low melt temperature thermoplastics. 89 Table 3.]. Selected Low Melt Temperature Of Thermoplastics. Temperature range of Energy Sr. No Material energy absorption OC absorption From i To in J / g Polyethylene Glycol MWz550, 1 PEG-27, Liquid form -10 25 69.69 Polyethylene Glycol Mw=750, 2 PEG-25, paste form 18 40 79 Polyethylene Glycol Mw=1000, 3 PEG-28, Paste form 24 50 111.9 Polyethylene Glycol Mw=600, 4 PEG—21, semi liquid form -5 25 108.7 Polycaprolactone triol, 5 Mw=900, PCT-29, paste form 33 49 0.2 Polyethylene glycol, Mn =900, 6 Hard paste form, PEG-34 18 37 127 Polyvinyl acetate Mw = 167000, 7 PVA-16, Pallet form 60 100 Negligible Polybutyl methacrylate Mw = 8 337000, PBM-l8, crystals form 32 37 Negligible Poly N-butyl methacrylate 9 PNBM-l 1, crystals form 27 52 1.8 90 energ \tithjj Of A; Table 3.1 (cont’d). 10 Poly Laurylactone, PLL-O4 4o 70 l 4.5 \ Poly caprolactone Diol Mn=530 T 11 Paste form, PCD-lS 41 45 7 Poly methyl methacrylate, 12 PMM-26, Crystalline 62 100 1.59 The results are viewed in the following. (1) Poly Ethylene Glycol (20248-7) PEG-27 with molecular weight of Mw Ca. 550. This material was in liquid state, and was discarded. The energy absorption during phase transition was found to be about 79 J/g, and it occurred within —10 to 25°C. The DSC test result is presented in Figure A-1of Appendix A. (2) Poly Ethylene Glycol (20249-5) PEG-25 with molecular weight of Mn Ca. 750. This material was in paste form at room temperature, and was discarded. The energy absorption during phase transition was found to be 95 J/ g, and it occurred within 18 to 40°C. The DSC test results for this material are shown in Figure A-2 of Appendix A. (3) Poly Ethylene Glycol (20242-8) PEG-28 with molecular weight of Mn Ca. 1000. This material was in paste at room temperature, and was discarded. In phase transition energy was about 95 J/g and it occurred within 24 to 50°C. The DSC results for this material are shown in Figure A-3 of Appendix A. (4) Poly Ethylene Glycol (20240-1) PEG-21 with molecular weight of Mn Ca. 600. This polymer was liquid at room temperature and thus discarded. The energy 91 absorpt 25°C ft of App (5,) P0 900. T key It energy 27-52' A-S o tempt relati‘ Show Was This figu —’——f absorption during phase transition was about 100J/g and it occurred within —-5 to 25°C for this polymer. DSC test results for this polymer are shown in Figure A-4 of Appendix A. (5) Poly Ethylene Glycol (37299—4) PEG-34 with molecular weight of Mn Ca. 900. This polymer was in a stable and hard past form, eventually emerged as the key low-melt temperature thermoplastic considered in this investigation. The energy absorption during phase transition was about123 J/ g and it occurred within 27-52°C for this polymer. DSC test results for this polymer are shown in Figure A-5 of Appendix A. (6) Poly Caprolactone Triol (20040-9) PCT—29 with molecular weight Mn Ca. 900. This material was in the paste form at room temperature. Its phase transition temperature was about 5 J /g and it occurred Within 33 to 49°C, which was relatively low and thus it was discarded. DSC test results for this polymer are shown in Figure A6 of Appendix A (7) Poly Vinyl Acetate (18248-6) PVA-16 with molecular weight of Mw Ca. 167000 (GPC). This material was in hard pallets shape at room temperature; the pallets were not brittle. The phase transition energy absorption of this material was less than 10 J/ g and it occurred within 60 to 100°C, which was relatively low. This polymer was thus discarded. DSC test results for this polymer are shown in Figures A-7 of Appendix A. (8) Poly Butyl Methacrylate (18152-8) PBM—18 with molecular weight of Mw Ca. 337000 (GPC). This material was in the form of hard at room temperature. Its 92 melt tern phase U‘E between (91 Poly crystalli and its j ttithin i probler room 1 the ca transi‘ 70°C . energ trial: melt temperature was relatively high about 120°C. It was thus discarded. The phase transition energy absorption of this polymer was less than 10 J/g occurred between 32 to 37°C. DSC test results are presented in Figure A-8 of Appendix A. (9) Poly N-Butyl Methacrylate (111) PNBM—l 1. This material was in hard crystalline state at room temperature. Its melt temperature was more than 100°C and its phase transition energy absorption was less than 20 J/ g and it occurred within 27 to 28°C. This material was discarded except for some compatibility problems. DSC test results for this polymer are shown in Figure A-9 of Appendix A (10) Poly Lauryllactom (044) PLL—04. This material was in crystalline state at room temperature with somewhat oily surface. When under high pressure it has the capacity to form into one single body because of its oily nature. Its phase transition energy absorption was just below 10 J/ g and it occurred within 40 to 70°C. DSC test results for this polymer are shown in Figure A-10 of Appendix A. (11) Poly Caprolactone Diol (18940-5) PCD-15 with molecular weight of Mn Ca. 530. This material was in crystals state at room temperature. In phase transition energy absorption was quite low, and it was discarded except for compatibility trials. DSC test results for this material are shown in Figure A-ll of Appendix A. (12) Poly Methyl Methacrylate (2003-6) PMM-26. This material was found to be in crystalline state at room temperature. Its melting temperature was more than 120°C and it was thus discarded. The phase transition energy absorption of this 93 polymer for this After st glycol ttith n10 to yerify this St and subjected t test results: Ta ecause it absr others latent hr polymer was less than 10 J/g and it occurred within 62 to 100°C. DSC test results for this polymer are shown in Figure A-12 of Appendix A. After screening of the thermoplastics, it was decided that PEG-34 poly ethylene glycol with molecular weight of 900 is the best material suiting our requirement; in order to verify this selection, poly ethylene glycol of different molecular weight were acquired and subjected to DSC tests. Figures A-13 through A-17 (in Appendix A) presents DSC test results; Table 3.2 summarizes the results. PEG-34 proved to be still available choice because it absorbed double quantity of latent heat within room temperature, while for others latent heat absorption occurs at elected temperatures. 94 Tabl a—«I "1'1 I) ”1‘1 U “1'1 .L'.) u-v-q 'I '1 None c LII C‘s resonable ser thermoplastics performance r thermoplastic: Table 3.2. DSC Test Results for Polyethylene Glycol of different Molecular weights. Energy Sr. No. Code Molecular Weight Range (if heat Absorbed absorptron C J /g 1 Poly (ethylene glycol)-34 Mn = 900 27-48 126.6 2 Poly (ethylene glycol)-38 Mn = 10000 53-85 135.75 3 Poly (ethylene glycol)-26 Mn = 2000 48-85 153.9 4 Poly(ethylene glycol)-3l Mn = 4600 62-82 191.7 5 Poly (ethylene glycol)-24 Mn = 3400 50-80 164.6 6 Poly (ethylene glycol)-22 Mn = 8000 53-75 165.73 None of the thermoplastics capable of substantial latent heat absorption provides reasonable serviceability and strength attributes within room temperature. These thermOplastics could be useful only if they are finely dispersed within a higher performance matrix materials within a blend. We can develop the following thermoplastics (Table 3.3) as the matrix in blends incorporating PEG-34. Table 3.3. Materials used to Test the Blend Behavior with PEG-34 Sr. Name of polymer Melt Temperature Latent Heat No. °C absorption J/ g 1 Polyethylene 1 02 Negligible 2 Polyamide Resin 117 10 3 Poly Vinyl Acetate 97 10 (PVA-3 7) 4 Poly Styrene 102 5 5 Zytel (Nylon) 259 Negligible Capron 6 Rynite Polyester 104 Negligible 7 Crastine PBT 225 Negligible 95 Polymer: through 7 were i DSC tests. saith Thermc extensively ant Anothe as the matrix y therefore selec 11) A fill Filled Polymers although were mixed with PEG-34 using a mixer, while polymers 5 through 7 were mixed using an extrusion. The above polymers were also subjected to DSC tests, with the with the results presented in Figure A-18 through A-24 of Appendix A. Thermoplastic No. 3 (PVA-3 7) showed the best promise and was investigated extensively and thoroughly. Another screening process was tracked; we realized that selection of thermosets as the matrix within the blend can help enhance temperature resistance of the system. We therefore selected the following thermosets for blending with PEG-34. (l) A filled epoxy EC-428 Resin Mast Cast Epoxy Adhesive system, Aluminum Filled with AD 932 Hardener, supplied by AD Tech Plastics (2) An Unfilled epoxy AD-932 Resin Epoxy Adhesive system With AD-932 Hardener, supplied by AD Tech Plastics. (3) An unfilled Polyester Resin 19 A Thixotropic Unfilled with BPO Hardener, supplied by AD Tech Plastics (4) An unfilled epoxy EC-439 Unfilled High Temperature Epoxy Casting System, supplied by AD Tech Plastics (5) A filled epoxy EC-433 Aluminum Filled, High Temperature Epoxy Casting System, Special for dimensional stability, supplied by AD Tech Plastics. 96 (6) A fil Requirern Plastics lhe follo but were disc These polyrn .11-26, A-27 t J) .._.A I.) [\J 2 p) The plastics) is reasonable ee‘ilkttsiye. liRPl. Re hpe only. sanctum] (6) A filled Polyester No. 15-3 Micro Ultra Filler Flame Retardant No burn Requirement, Boeing Spec: BMS-5-136A, With BPO hardener, supplied by AD Tech Plastics The following polymers were also considered at various stages of the investigation, but were discarded due to high cost or other problems like incompatibility with PEG-34. These polymers are listed below, with their DSC test results presented in Figures A-25, A-26, A-27 of Appendix A. (1)1-Dodecanol Tm=24-27°C Boiling Point = 260°C with latent heat absorption of 180 J/g in temperature range of 18 to 40°C. (2) Hytral-7246 Tm = 217°C (3) Bolwax No. 1 Tm = 70°C 3.1.2. m 3.1.2.1 Glass Fibers The most widely used reinforcing fiber is glass. The term ‘GRP’ (glass reinforced plastics) is often used within the composite industry. The glass most used is E-glass with reasonable chemical resistance; S-glass with higher strength and modulus is but it is more expensive. E-glass is the ‘workhorse’ of the whole fiber reinforced plastics industry (F RP). Keeping in View the characteristics of E-glass fibers it was decided to use this type only. The fibers were required to make the blend/composite strong as far as its structural behavior is concerned. The following fibers were selected initially: (l) Chopped E-Glass fibers 2-3mm long with diameter of 10pm. (2) Chopped E—Glass fibers 2-3mm long with diameter of 17pm. 97 (3) Che Glass f our iny’estigatit 3.1.2.2 Cellult _—.——— Proces was selected I 3.1.3. Tillers Many For lhe Carbon Particle 5'12 during the this tiller 1 (3) Chopped E-Glass fibers 12mm long. Glass fiber No. 1 exhibits better dispensability in our blend, and was selected for our investigation. 3.1.2.2 Cellulose Fibers Processed cellulose fibers (softwood Kraft pulp) with a brand name of F abrosetR was selected to be used in the blends for the enhancement of structural properties. 3.1.3. Fillers Many of the thermoset systems selected for use in this investigation were already filled. With some unfilled blends, we used the following filler materials. (1) Carbon Black (2) Silica (3) Calcium Carbonate For this investigation, we chose carbon black (supplied by Cabot Corporation). The carbon black selected was; Fluffy Regal 330 R and Pallets Regal 330, with 25 mm particle size. An idea of using lightweight glass micro spheres as filler was also suggested during the course of this study, but unfortunately time did not allow to acquire and use this filler material. 98 .2. F ABRlC.A fl 3 Cornpr materials. The 3.2.1. __l_olii. for th dimensions 1‘ tlllf (31 3 We t tschernaticai plunger hay" compressior in. The not \tithout ind \tere 305m 3.2. FABRICATION Compression molding dominates processing of products incorporating the materials. The application of compression molding to our study is discussed below. 3.2. 1. Mold. For the purpose of laboratory testing, we needed a sample of the following dimensions (we chose a thickness of 12 mm for our samples). ( 1) 152mm x 12mm (2) 305mm x 55mm We used one mold out of which the above samples could be cut. The mold (schematically shown in Figure 3.1) was made out of high carbon steel material, with the plunger having a seating gap of about 0.01mm. This was selected so that during compression molding, the material could not flow out while the plunger block was forced in. The mold was made in three pieces so that de—molding could be done conveniently without inducing harmful stresses on the sample. The dimensions of the mold selected were 305mm x 152mm x 19mm. 99 For tequirenter thermosets 3-3-3. Con ‘ C or desired sh Eliected b lhe mold . memIOSet Winters chetttical 3&3;me F ‘t 1: Figure 3.1. The Shape of the Mold. For tensile strength tests the dog bone samples were required, to meet this requirement, molds were prepared from aluminum and silicon for thermoplastics and thermosets, respectively. 3.2.2. Compression Molding Machine Compression molding consists of forcing a certain amount of polymer into the desired shape of the mold cavity, not by injecting it into a closed mold. The compression, effected by a hydraulic press, results in the intimate contact of the polymer charge with the mold and a squeezing type of flow that fills the cavity. The process is widely used for thermosetting polymers, although it is also applicable, in principle, for thermoplastic polymers. Heat is conducted from the hot mold walls to the polymer, inducing the chemical process of polymerization and cross-linking. Compression molding has certain advantages: the molds are simpler than used in special injection molding, fillers remain 100 relatiyely undE are geometric: machine used process of ap] mold: subseq temperature ( below: Fig Peint of y“ reS1011 of N heate forced 10 relatively undamaged, and little material is wasted. But the process is slower, and there are geometrical limitations with respect to the parts that can be molded. The compression machine used for this purpose has the capability to heat the platens before and during the process of applying pressure. The polymers were first blended and then placed in the mold; subsequently the mold was fixed within the compression machine (preheated to a temperature of 60°C). The compression force vs. schematically shown in Figure 3.2 below: Compression , Plunger Force / Heatup of Polymer Flow / Time Figure 3.2. The curve showing various stages of compression molding. Figure 3.2 represents various stages of the compression molding cycle from the point of view of the plunger force needed to close the mold at a constant rate. In the first region of polymer heat up, the force is set to increase rapidly as the charge is squeezed and heated. At this stage, the polymer is presumably in the molten state and, as such, is forced to flow in the cavities and comers and fill equally. Filling terminates at the next 101 rising curve F de—molding s 5 . '3 y't- ‘JJ Mixir B thoroughly n form of the 1 processing. ' lmfllsly‘e rising curve range. After compression ending, the mold is removed from the machine and de-molding starts. 3.2.3 Mixing and Blending Facilities Before a polymer blend can be further processed, it usually needs to be thoroughly mixed. The mixing processes also provide an opportunity to alter the physical form of the polymer so that it is readily handled at the final conversion stage of its processing. The types of mixing available are listed below: 0 Extensive mixing 0 Intensive mixing 0 Blending o Compounding o Mixing 0 Dispersion o Distributive mixing 0 Dispersive mixing After taking into consideration our polymer materials, the intensive/dispersive-mixing method was selected in our study. For this purpose the machines introduced below were used to mix our materials. 102 a shaped die or conyeyin fitting close Solid polyn other. lnsid 30mm Tyti 3.2.3.1 Mixing Systems 3 .2.3 . 1 . 1 Extrusion Machine The extrusion process comprises forcing of a plastic or molten material through a shaped die by means of pressure. Twin-screw extruders are used where superior mixing or conveying is important. The machine consists essentially of Archimedean screws fitting closely in a cylindrical barrel, with just sufficient clearance to allow its rotation. Solid polymers are fed in at one end and the profiled molten extrudate emerges from the other. Inside, the polymer melts and homogenizes. We used Werner-Pf leidderer ZSK 30mm Twin Screw Extruder Figure 3.3 with the following characteristics. 26:1 Aspect Ratio. 0 4 Feed Ports for Multiple Component Blending. 0 Gravimetric and Volumetric Feeders for Powders, Pellets, and Chips. 0 Rotary Knife Pelletizer. 0 Four Independent Heating Zones. 103 LA) IJ J.) :__. i) ”—1 used for tl Change ca dpinsnr dlSttibutiy and (lurin snudnnn mixer. w cOlttainer Figure 3.3. Extrusion machine. 3.2.3.1.2 Dip Mixer (Cowles Dissolver) Low Viscosity liquid blends are made with a dip mixer. A Cowles dissolver was used for this purpose. In this device the stirrer is dipped into the mix contained in a change can. This denotes that the container may be changed and the mixer is a simple dip-in stirrer. Dip mixer is a low shear device. This machine possesses the ability for distributive or extensive mixing. In this study, thermoplastics had to be molten prior to and during mixing. For this purpose a set-up was devised to heat the thermoplastics and simultaneously stir the blend. A medium size aluminum pot was also used with the dip mixer, with electric heating systems in the base plate. The material was placed in container and fixed in the heating pot (Figure 3.4). 104 J) J) .__. U SCan ‘ The DS materials. 11 capable of or used occasio Figure 3.4. Heating And Mixing Set Up For This Study. 3.3 TEST SETUP 3.3.1 DSC and Other Thermal Test Systems The DSC test system was used to test the latent heat absorption characteristics of materials. The (TA) Thermal Analysis system used for this purpose (Figure 3.5) was capable of operating within -60°C to 725°C. The following thermal test system, were also used occasionally in our research: 0 TGA Instrument. 0 TMA Instrument. 105 The TG. of materials. y Figure 3.5. DSC Test Systems. 3.3.2 TGA Instrument The TGA instrument (Figure 3.6) is used to determine the degradation temperature of materials, which is necessary for high temperature processing (e.g., extrusion). Figure 3.6. TGA instrument. 3.3.3 TMA Instrument The TMA instrument (Figure 3.7) is used to determine the thermal expansion coefficient of materials. 106 3.3.4 Eny'ironr This insr of blend morp this iny'estigat 4.! Figure 3.7. TMA Instrument. 3.3.4 Environmental Scanning Electron Microscopy This instrument is used to take images at broad magnifications for the investigation of blend morphology. The environmental Scanning Electron Microscope (ESEM) used in this investigation is shown in Figure 3.8. Figure 3.8. Environmental Scanning Electron Microscopy. 3.3.5 Tensile tests The tensile performance of different polymer blends and composites were measured using a temperature controlled hydraulic test system (Figure 3.9). The 107 extensonteter i1 gage length of 34m We sought and composite 10131 \teightl. extensometer in this investigation we used infrared beam to track down elongation for a gage length of 51mm (2 inches). Figure 3.9. Tensile strength testing machine. 3.4 PREPARATION OF SAMPLES We sought to replicate each test at least three times. The following polymer blends and composites were processed and tested for this investigation (all proportions are by total weight). 3.4.1 Slabs without Compression Molding. a. Slab # A-l - Flame Retardant (15-3) + PEG-34 (60+40)+ 4 % Glass fiber + 0.8 % Hardener (BPO) b. Slab # A-2 - Flame Retardant (15—3) + PEG-34 (60+40)+ 3 % Glass fiber + 0.8 % Hardener (BPO) C. Slab # A-3 - Flame Retardant (15-3) + PEG-34 (60+40)+ 20 % Glass fiber + 0.8 % Hardener (BPO) 108 d. Slab 0.8‘ e. Slat 0.8 3.42M °/ol b. Sla 0],. c. 812 °/o °/o “to m Slab # A-4 - Flame Retardant (15-3) + PEG-34 (60+40)+ 2 % Glass fiber + 0.8 % Hardener (BPO) Slab # A-5 - Flame Retardant (15-3) + PEG-34 (60+40)+ 10 % Glass fiber + 0.8 % Hardener (BPO) 3.4.2 Slabs with Compression Moldg. a. Slab # 1 - Flame Retardant (15-3) + PEG-34 (60+40)+ 10 % Glass fiber + 1.4 % Hardener (BPO) Slab # 2 - Flame Retardant (15-3) + PEG-34 (60+40)+ 10 % Glass fiber + 1.4 % Hardener (BPO) Slab # 3 - Flame Retardant (15-3) + PEG-34 (60+40)+ 15 % Glass fiber + 1.4 % Hardener (BPO) Slab # 4 - Flame Retardant (15-3) + PEG-34 (60+40)+ 10 % Glass fiber + 1.4 % Hardener (BPO) Slab # 5 - Flame Retardant (15-3) + PEG-34 (66+33)+ 10 % Glass fiber + 1.4 % Hardener (BPO) Slab # 6 - Flame Retardant (15-3) + PEG-34 (60+40)+ 2.2 % Cellulose fibers + 1.4 % Hardener (BPO) Slab # 7 - Flame Retardant (15-3) + PEG-34 (60+40)+ l % Cellulose fibers + 1.4 % Hardener (BPO) Slab # 8 - Flame Retardant (15-3) + PEG-34 (60+40)+ 1 % Cellulose fibers + 1.4 % Hardener (BPO) Slab # 9 - Flame Retardant (15-3) + PEG-34 (60+40)+ No Fibers + 1.4 % Hardener (BPO) 109 j, Slab= 1.4 a k. Slab : 3.4.3 Final Set c results obtained a. Slab % H d. Slat 0 0 H s‘- Slat ‘0 j. Slab # 10 - Flame Retardant (15-3) + PEG-34 (80+20)+ 10 % Glass fibers + 1.4 % Hardener (BPO) Slab # 11 - Flame Retardant (15-3) + PEG-34 (80+20)+ 1 % Cellulose fibers + 1.4 % Hardener (BPO) Slab # 12 - Flame Retardant (15-3) + PEG-34 (85+15)+ 5 % Glass fibers + 1.4 % Hardener (BPO) Slab # 13 - Flame Retardant (15-3) + PEG-34 (65+35)+ 0.5% Cellulose fibers + 1.4 % Hardener (BPO) Slab # 14 - Flame Retardant (15-3) + PEG-34 (65+35)+ 1% Cellulose fibers + 1.4 % Hardener (BPO) 3.4.3 ma] Set of Slab Samples. These slabs were finally prepared after evaluating the results obtained with above blends. Notation F means these are the final series of slabs. a. Slab # F 1 - Flame Retardant (15-3) + PEG-34 (65+35)+ 5% Glass fibers + 2 % Hardener (BPO) Slab # F 1+2 - Flame Retardant (15-3) + PEG-34 (65+35)+ 5% Glass fibers + 2 % Hardener (BPO) (cast again) Slab # F2 - Flame Retardant (15-3) + PEG-34 (65+35)+ 10 % Glass fibers + 2 % Hardener (BPO) Slab # F3 - Flame Retardant (15-3) + PEG-34 (65+35)+ 20 % Glass fibers + 2 % Hardener (BPO) (not good slab) Slab # F 3+1 - Flame Retardant (15-3) + PEG-34 (65+35)+20% Glass fibers + 2 % Hardener (BPO) 110 Ill. Slal Hat f. Slab # F4 - Flame Retardant (15-3) + PEG-34 (65+35)+ No Fibers + 2 % Hardener (BPO) g. Slab # F5 - Flame Retardant (15-3) + PEG-34 (80+20)+ No Fibers + 2 % Hardener (BPO) h. Slab # F6 - Flame Retardant (15-3) + PEG-34 (80+20)+ 5% Glass fibers + 2 % Hardener (BPO) i. Slab # F7 - Flame Retardant (15-3) + PEG-34 (80+20)+ 10 % Glass fibers + 2 % Hardener (BPO) j. Slab # F8 - Flame Retardant (15-3) + PEG-34 (80+20)+ 20 % Glass fibers + 2 % Hardener (BPO) k. Slab # F9 - Flame Retardant (15-3) + PEG-34 (65+35)+ 1 % Cellulose fibers + 2 % Hardener (BPO) l. Slab # F10 - Flame Retardant (15-3) + PEG-34 (65+35)+ 1.5 % Cellulose fibers + 2 % Hardener (BPO) m. Slab # F 11 - Flame Retardant (15-3) + PEG-34 (80+20)+ 1 % Cellulose fibers + 2 % Hardener (BPO) n. Slab # F12 - Flame Retardant (15-3) + PEG-34 (80+20)+ 1.5 % Cellulose fibers + 2 % Hardener (BPO) 111 4.1 @133 This cl heat absorptio which absorbs temperature p chapter lead It the next chap 4.2 w 4.3.1 mpg Our it absorptionl latent heat \y our selected selected base CHAPTER 4 PRELIMINARY EXPERIMENTAL RESULTS 4. 1 GENERAL This chapter reviews processability of different polymer blends and their latent heat absorption characteristics also, noting that our goal is produce a polymer blend which absorbs latent heat while remaining solid and retaining a substantial fraction low temperature physical properties at elevated temperatures. The results presented in this chapter lead to the selection of our final blends and composites, which are discussed in the next chapter. 4.2 CHARACHTERIZATION OF MATERIALS 4.2.1 Energy Absorption Our investigation started with DSC tests of the materials selected for energy absorption. The important issue here was to select a material, which absorbs substantial latent heat within the room temperature range. The energy absorption characteristics of our selected low-melt-temperature thermoplastics are presented in Table 4.1. PEG-34 was selected based on the results of Table for further investigation. 112 . Sr. No b) T Table 4.1. DSC Test Results For Low-Melt-Temperature Thermoplastics. Temperature Energy Sr. No Material range of energy absorption absorption °C in J/g From To Polyethylene Glycol Mw=550, 1 PEG-27, Liquid form -10 25 69.69 Polyethylene Glycol Mw=750, 2 PEG-25, paste form 18 40 79 Polyethylene Glycol Mw=1000, 3 PEG-28, Paste form 24 50 111.9 Polyethylene Glycol Mw=600, 4 PEG-21, semi liquid form -5 25 108.7 Polycaprolactone trio], 5 Mw=900, PCT-29, paste form 33 49 0.2 Polyethylene glycol, Mn =900, 6 Hard paste form, PEG-34 18 37 127 $ Polyvinyl acetate Mw = 167000, 7 PVA—16, Pallet form 60 100 Negligible _ Polybutyl methacrylate Mw = 8 337000, PBM-18, crystals form 32 37 Negligible 113 The charactt Tlgure 4.l j Table 4.1 (cont’d). Poly N-butyl methacrylate 9 PNBM-l 1, crystals form 27 52 1.8 10 Poly Laurylactone, PLL-04 40 70 4.5 Poly caprolactone Diol Mn=530 11 Paste form, PCD-15 41 45 7 Poly methyl methacrylate, 12 PMM-26, Crystalline 62 100 1.59 The characteristic of PEG-34 are is presented below: Figure 4.1 presents a typical test result for PEG-34. Name Appearance Flash point (°C) Average Molecular weight Softening Temperature (°C) Viscosity CST pH 114 Poly (ethylene glycol) White waxy solid > 110 MW = 900 32-36 15-17 4.5-7.5 PE( TGA test 5: any form sr I61111333111111 SF’Stent \xhj engineering 4.2.2 & Stre TeaSOItably relathely l. :1 .4 \k Energy absorption == 133 J/g Figure 4.1. A Typical DSC Test Result for PEG—34. PEG—34 melts slowly, shows only about 5% weight loss at about 250°C during TGA test system. One of the disadvantages of PEG-34 is that it cannot be formed into any form suiting engineering applications due to its soft and waxy nature at room temperature. Therefore, it should be finely dispersed in a structural matrix to yield a system which complements energy absorption with strength and serviceability for engineering applications. 4.2.2 Strength and Serviceability Strength and serviceability requirements for building applications are the key reasonably our source of energy absorption (PEG—34) is blended with a polymer of relatively high strength, stiffness and temperature resistance. We used the following criteria to asses the strength and serviceability of our polymer blend composites. 0 Tensile strength and elongation capacity at different temperatures. 0 Moisture absorption. 115 The the: meeting strt materials is T 4.2 BE A d. POlymel- as were Set at thinner-slag. COHgfimenL‘ 0 Density. 0 Resistance to elevated temperatures. The thermosets or high melt temperature thermoplastics blended with PEG-34 for meeting strength and serviceability demand are listed in Table 4.2. The list of selected materials is placed in Table 4.2. Table 4.2. Materials used for blending with PEG—34 (binder materials) Sr. No. Name of Material 1 Poly vinyle acetate 2 Polyamide Resin 3 Polyethylene 4 Poly Styrene 5 Poly Bug/l Methacrylate 6 Poly N-butyl Methacgllate 7 Claurylactam Nylon 12 8 Nylon Resin Zytel 9 Rynite-555 BK 506 Thermqalastic Polyester 10 Crastin PBT S 610 NCO 1O 11 Nylon with 33 % Glass Fibers 12 EC-482 Resin Mast Cast Epoxy Adhesive System 13 AD-932 Resin Epoxy Adhesive system 14 Polyester Resin 19 A 15 EC-439 Unfilled Epoxy castingsystem 16 EC-433 Aluminum Filled Epoxy 17 No. 15-3 Micro ultra filler flame retardant 4.2.1 Blending Methods 4.2.1.1 Extrusion A double screw was used to mix our low melt temperature thermoplastic with the polymer acting as the structural matrix. Temperatures of all the zones within the extruder were set at 10 to 20°C higher than the melt temperature of the high temperature thermoplastic (the structural matrix). The extreme difference in melt temperature of the constituents of our blend caused major problems during the extrusion process. This led to 4.2 BLENDING OF MATERIALS 116 separation < introductior segregation 34 melt (Wl make effec 4.2.1.2 m Sin: a homo gen. placed in er thermosets heated ytitl: for mixing. PVA ~16 a ml\lllg Was seEiregation exhibited Pt ”I Ohyiou IDOre Comp 301%an if separation of the low melt temperature polymer (which melted immediately upon introduction to the extruder) from the high melt temperature thermoplastics. This segregation tendency seemed to be further incurred for the high Viscosity nature of PEG- 34 melt (which could not be conveyed satisfactorily by screws). Therefore, we could not make effective use of the extrusion process in this investigation. 4.2.1.2 Blending with Heated Mixer Simultaneous heating and stirring of the blend found to be effective in producing a homogenous blend in this investigation. The container incorporating the blend was placed in engine oil heated for our targeted mixing temperature (about3 0°C) with thermosets and about the melt temperature of the high temperature thermoplastics to be heated within the blend. All thermoplastics were melted before introduction to the blend for mixing. 4.2.2 Blending Of PEG-34 With Thermoplastics 4.2.2.1 PVA-16 (Tm =60°C) +PEG-34 The initial proportion tried for this composition was 50% + 50% by weight of PVA —16 and PEG-34. After heating PVA-16 and melting it, PEG-34 was added and mixing was done for about 5 minutes. The mix seemed homogenous with no obvious segregation of phases. After the blend solidified, it was subjected to DSC test. The blend exhibited relatively high latent heat storage capacity within room temperature without any obvious sign of melting. Blends of PVA-16 with PEG-34 were thus subjected to a more comprehensive investigation. The blend compositions, DSC test results and softening temperatures are presented in Table 4.3. The DSC test results are observed to 117 be quite satis description c presented in Table 4.3 P\ l s. #WN—l OCOCDNODC.” .4 l .4. .__|. l [ginlasialxlalasl be quite satisfactory; the softening temperatures are however, relatively low. A typical description of the softening and melting process for PVA-16 and PEG-34 blends is presented in Table 4.4. Table 4.3 PVA—16: PEG—34 blend compositions and DSC test results. Sr. Tempera Energy Softening Sample Proportion ture Absorption No. Rangfc J/g temperatures 1 PVA-16+PEG—34 (50+50) 21 to 37 41.5 45°C 2 PVA-16+PEG-34 (50+50)+1 %GF 19 to 40 47.5 45°C 3 PVA-16+PEG-34 (50+50)+2%GF 15 to 37 49.81 45°C 4 PVA-16+PEG-34 @0+50)+3%GF 22 to 40 33.74 45°C 5 PVA-16+PEG—34 @0+50)+4%GF 19 to 37 35.78 45°C 6 PVA-16+PEG—34 (50+50)+5%GF 22 to 36 32.89 45°C 7 PVA-16+PEG—34 (50+50)+10%GF 16 to42 31.61 45°C 8 PVA-16+PEG34 (60+40)+4%GF 18 to 45 25.14 45°C 9 PVA-16+PEG—34 (60+40)+5%GF 22 to 36 22.3 45°C 10 PVA-16+PEG-34 (60+40)+10%GF 19 to 39 20.85 45°C 11 PVA-16+PEG—34 @0+4%20%GF 21 to 40 19.71 45°C 12 PVA-16+PEG—34 (50+50)+0.1%Fabroset 18 to 35 37.05 45°C 13 PVA-16+PEG-34 (50+50)+0.2%Fabroset 19 to 37 42.5 45°C 14 PVA-16+PE334 (50+50)+O.3%Fabroset 18 to 38 39.25 45°C 15 PVA-16+PEG-34 (50+50)+0.4%Fabroset 17 to 38 37.85 45°C 16 PVA-16+PEG-34(60e401+0.1°/0Fabroset 19 to 35 25.5 45°C 17 PVA-16+PEG—34 (60+40)+0.2%Fabroset 21 to 40 23.6 45°C 18 PVA-16+PEG-34 (60+40)+0.3%Fabroset 20 to 35 29.05 45°C 118 Table 4.4 D 4.3.2.2 PVA ‘ Table tiller used in blends is sat: the Proportic r00m temper 37:PEG-34 ( psil Table 4.4 Description of the softening and melting behavior of PVA- 1 6+PEG-34 (50+50) with temperature increase. Temp 0C 10 Physical State ] mmutes stage The blend was oily and flexible 25 30 No further change, the material had no effect 35 Plastic and oily, can be molded easily T Started to transform into paste 45 Paste behavior 50 60 Started flowing. 4.3.2.2 PVA-37 (Tm = 97°C) + PEG-34 Table 4.5 shows the PVA-37: PEG-34 blends considered in this investigation. The filler used in these blends was carbon black. Again the heat storage capacity of these blends is satisfactory but their softening temperature is still low. A typical observation of the proportions of these blends and softening temperatures is presented in Table 4.6. At room temperature, PVA-37: PEG-34 exhibited reasonable strength, for example PVA- 372PEG-34 (65:35) with carbon black filler had a tensile strength of about 1.05 Mpa (150 psi) 119 Table 4.5 PVA-37: PEG-34 Blend Composites and DSC Test Results. Sr Range of Energy Softening No Material Nomenclature Temperature Absorption Temperat ' °C J/g ure 1 PVA-37+PEG-34 (50+50)+No Fiber 19-37 22.5 60°C 2 PVA-37+PEG-34 (50+50)+1% Glass Fiber 21-35 55.7 60°C 3 PVA-37+PEG-34 (50+50)+2% Glass Fiber 18-40 18.8 60°C 4 PVA-37+PEG-34 (50+50)+3% Glass Fiber 21-40 18.6 60°C 5 PVA-37+PEG-34 (50+50)+5% Glass Fiber 22-43 23 60°C 6 PVA-37+PEG-34 (50+50)+10% Glass Fiber 21-40 29.5 60°C 7 PVA-37+PEG-34 (50+50)+20% Glass Fiber 18—37 25.7 60°C 8 PVA-37+PEG-34 (50625130 Fiber+33%of PVA-37 20_35 26.74 60°C PVA-37+PEG-34 (50+50)+1% Glass Fiber+33%of _ o 9 PVA-37 Filler 21 38 21 6° C PVA-37+PEG-34 (50+50)+2% Glass Fiber+33%of _ 0 1° PVA-37 Filler 18 37 47 6° C PVA-37+PEG-34 (50+50)+3% Glass Fiber+33%of _ 60°C 11 PVA-37 Filler 19 3° 5° PVA-37+PEG-34 (50+50)+4% Glass Fiber+33%of 8 60°C 12 PVA-37 Filler 184° 5 13 PVA-37+PEG-34 (50+50)+5% Glass F iber+33%of 21_37 47 60°C PVA—37 F Iller 14 PVA-37+PEG-34 (50+50)+10% Glass Fiber+33%of 1940 42 60°C PVA-37 Filler 15 PVA—37+PEG-34 (50+50)+20% Glass Fiber+33%of 21-38 38 60°C PVA-37 Filler- 16 PVA-37+PEG-34 (55+45)+No Fiber 20-41 19.8 60°C 17 PVA-37+PEG-34 (55+45)+1% Glass Fiber 19-37 39 60°C 18 PVA-37+PEG-34 (55+45)+2% Glass Fiber 22-40 50 60°C 19 PVA-37+PEG-34 (55+45)+3% Glass Fiber 21-38 54 60°C 20 PVA-37+PEG-3 (55+45)+5% Glass Fiber 21-36 42 60°C 0 21 PVA-37+PEG-34 (55+45)+10% Glass Fiber 19-45 38 60 C O 22 PVA-37+PEG-34 (55+45)+20% Glass Fiber 20-38 32 60 C 120 23 24 25 126 €27 £28j Table 4.5 (cont’d). 23 PVA-37+PEG-34 (60+40)+No Fiber 21-36 29 6000 24 ‘ PVA-37+PEG-34 (60+40)+1% Glass Fiber 21-35 31 60°C 25 PVA-37+PEG-34 (60+40)+2% Glass Fiber 19-40 22 60°C 26 PVA-37+PEG-34 (60+40)+3% Glass Fiber 23-40 19 60°C 27 PVA-37+PEG-34 (60+40)+5% Glass Fiber 15-37 21 60°C 28 PVA-37+PEG-34 (60+40)+10% Glass Fiber 18-42 27 60°C 29 PVA-37+PEG-34 (60+40)+20% Glass Fiber 21-40 23 60°C 30 PVA-37+PEG—34 (65+35)+1% Glass Fiber 22-42 25 60°C 31 PVA-37+PEG-34 (65+35)+2% Glass Fiber 21-38 36 60°C 32 PVA-37+PEG-34 (65+35)+3% Glass Fiber 22-40 25 60°C 33 PVA-37+PEG-34 (65+35)+5% Glass Fiber 22-39 31 60°C 34 PVA-37+PEG-34 (65+35)+10% Glass Fiber 21-40 29 60°C R35 PVA-37+PEG-34 (65+35)+20% Glass Fiber 21-40 35 60°C __36 PVA-37+PEG-34 (50+50)+0.1% Cellulose Fiber 19-37 24 60°C 37 PVA-37+PEG-34 (50+50)+0.2% Cellulose Fiber 18-35 37 60°C 3 PVA-37+PEG-34 (50+50)+0.3% Cellulose Fiber 21-38 32 60°C :9 PVA-37+PEG-34 (50+50)+0.4% Cellulose Fiber 19-36 33 60°C 73 PVA-37+PEG-34 (50+50)+0.5% Cellulose Fiber 18-39 36 60°C 7 PVA-37+PEG-34 (60+40)+0.1% Cellulose Fiber 19-38 35 60°C ? PVA-37+PEG-34 (60+40)+0.2% Cellulose Fiber 21-38 37 60°C 7; PVA-37+PEG-34 (60+40)+0.3% Cellulose Fiber 20-40 23 60°C T4 PVA-37+PEG-34 (60+40)+0.4% Cellulose Fiber 21-39 27 60°C 7; PVA-37+PEG-34 (60+40)+O.5% Cellulose Fiber 22-40 28 60°C : PVA-37+PEG-34 (65+35)+0.1% Cellulose Fiber 21-38 37 60°C 121 Table 4.5 (cont'd). 47 PVA-37+PEG-34 (65+35)+0.2% Cellulose Fiber 20-38 29 60°C 48 PVA-37+PEG-34 (65+35)+0.3% Cellulose Fiber 21-40 12 60°C 49 PVA-37+PEC-34 (65+35)+0.4% Cellulose Fiber 19-38 15 60°C 50 PVA-37+PEG-34 (65+35)+0.5% Cellulose Fiber 21-36 2 60°C 51 PVA-37+PEG-34 (70+30)+0.1% Cellulose Fiber 19-40 12.8 60°C 52 PVA-37+PEG-34 (70+30)+o.2% Cellulose Fiber 21—41 1.15 60°C 53 PVA—37+PEG-34 (70+30)+0.3% Cellulose Fiber 20-38 1.26 60°C 54 PVA-37+PEG-34 (70+30)+o.4% Cellulose Fiber 2140 3.225 60°C 55 PVA-37+PEG-34 (70+30)+O.5% Cellulose Fiber 22-40 5.65 60°C 56 PVA-37+PEG-34 (70+30)+N0 Fiber 21-38 7.65 60°C 57 PVA-37+PEG-34 (70+30)+2% Glass Fiber 22-40 32.81 60°C 122 Table 4 Table 4.6. Softening Temperature of PVA-37: PEG-34 (50:50) with Temperature increase Time Temp 0C Observation 1:15 pm 30 Hard and stiff 1:25 pm 35 Waxy surface 1:35 pm 40 Slightly plastic 1:45 pm 45 Completely plastic 1:55 pm 50 Gradual formation of paste 2:05 pm 55 Segregated paste 2:15 pm 60 Completely paste formation 4.3.2.3 PLL-04 (Tm=980C) + PEG-34 These two polymers were not miscible; they segregated during solidification. 4.3.2.4 PBM-18 + PEG-34 These two polymers were not miscible; they segregated during solidification 4.3.2.5 PNBM (Tm = 120°C) + PEG-34 These two polymers were not miscible; they segregated during solidification. 123 4.3.2.6E1h The 10 OCCUT 631' ofNylon 6 ‘ 4.3.2.7 13m This previously l 4.3.2.8 C_ra lhi extrusion. ' 4.3.3.9 313 Th1 SITUCiural r 4.3.2.6 Nylon 6 (Tm= 225°C) + PEG-34 The blend was processed in the extruder after initial mixing. Segregation started to occur early in the extruder upon exit also problem were caused by quick solidification of Nylon 6 while PEG-34 was still liquid. This blend was thus discarded. 4.3.2.7 Rynit 555 Bk 506 Thermoplastic Polyester (Tm = 104°C) +PEG-34 This blend was mixed and extruded, it exhibited segregation tendencies similar to previously observed with Nylon 6: PEG-34 blend. This composition was also discarded. 4.3.2.8 Crastine (PBT) (Tm = 243°C) + PEG-34 This blend was prepared by mixing while PBT is still in solid state, followed by extrusion. The composite was discarded due to segregation 4.3.2.9 PEG-34 + PEG with Higher Molecular Weights This effort was made to use the following higher molecular weight PEG’s as the structural matrix for PEG-34. 124 Sr. N -J (J) condition. ' exhibited e 4.3.2.1013 Al lelIlg am 4.3.2.11 P. ~ Sr. No Name of Material Code Molecular weight Tm OC 1 Polyethylene glycol PEG-26 2000 55 2 Polyethylene glycol PEG-24 3400 62 3 Polyethylene glycol PEG-31 4600 65 4 Polyethylene glycol PEG-22 8000 72 5 Polyethylene glycol PEG-38 10000 85 The above PEG’s were mixed with PEG-34 (50: 50 weight ratio) in melt condition. The molten blend looked homogenous; upon cooling however, the system exhibited excess cracking and disintegration. These blends were therefore discarded. 4.3.2.10 Polvamide Resin (Tm = 117°C ) + PEG-34 At 50: 50 weight ratio, this blend exhibited strong segregation tendencies during mixing and cooling processes. It was thus discarded. 4.3.2.11 Polyethlene(Tm = 107°C) + PEG-34 This blend at 50: 50 weight fraction exhibited strong segregation tendencies during cooling processes was thus discarded. 4.3.2.12 Poly Styrene(Tm = 102°C) + PEG-34 This blend was also discarded due to segregation tendencies during cooling. 125 heat storage of these ble 0 P01) ObSt 0 PC ". 0 Polj “'38 8.5%. at 30°C. 11 ePoxies. T Fiiure 4.2 lelllS blend 4.3.2.13 Miscellaneous Bleng These trial blends of PEG-34 with other thermoplastic of relatively higher latent heat storage capacity with somewhat higher melt temperatures were also prepared. Some of these blends are introduced below. 0 Poly N-Butyl Methacrylate + PCT-29 (50+50) —Segregation tendencies were observed. 0 PCT-29 + PLL-04 (50+50) — Segregation tendencies were observed. 0 Polyethylene + PEG-22 (50+50) — Segregation tendencies were observed. 0 PLL-04 + PEG-24 (50+50) Segregation tendencies were observed. 4.3.3 B¥LENDING WITH THERMOSETS Our efforts to use higher melt temperature thermoplastics with PEG-34 yielded limited success. We therefore focused on use of Thermosets as the structural matrix for PEG-34. 4.3.3.1 Blend Compositions and Performance 4.3.3.1.] EC-428 Resin Mass Cast Svstem + PEG-34 This epoxy is an aluminum filled resin; the recommended dosage of hardener was 8.5%. PEG-34 was melted before hand, and mixed with epoxy (50: 50 weight ratio) at 30°C. Higher mixing temperatures could cause premature curing (hardening) of epoxies. The blend was quite homogenous with no obvious segregation tendencies. Figure 4.2 presents the DSC test result for this blend. The latent heat storage capacity of this blend was relatively low (< 5 J/g). 126 dosage an liigure 4. q E _ nergy abosorption = 44J Ig ‘kffib¥ _ Figure 4.2. Test result for Epoxy EC-428 + PEG-34 (50:50) 4.3.3.1.2 AD-932 Resin Epoxy Adhesive Svstem +PEG-34 This blend was mixed at 30°C with 70: 30 weight ratios using the hardener dosage and combinations recommended by the manufacturer of epoxy (this epoxy cures at about room temperature). This blend was quite homogenous and DSC test results (Figure 4.3) indicated a reasonably high latent heat storage capacity (about 23 J/g). 127 L2) 2.... 1.4.) manufacr blend, 1}] 4.4) and ' Surface \\ Energy absorption = 28 J/g Figure 4.3. Test results for Epoxy 932 + PEG-34 (70+3 0) 4.3.3.1.3 Unfilled Polyester Resin 19-A Thixotropic Unfilled Epoxy +PEG-34 This blend was investigated using the following proportions. 0 Polyester -19 A + PEG-34 (50+50) 0 Polyester -19 A + PEG-34 (60+40) 0 Polyester -19 A + PEG-34 (65+35) 0 Polyester -19 A + PEG-34 (70+30) 0 Polyester -19 A + PEG-34 (80+20) The hardener (BPO) was used at the dosage recommended by the manufacturer. The mixing process was quite satisfactory and yielded a homogenous blend. The latent heat storage capacities of the system was also reasonable (see Figure 4.4) and Table 4.7. the blend was resistant to temperatures exceeding 120°C where surface was somewhat waxy but then blend retained its structural integrity. 128 Table A “l—TTWT Energy absorption = 33 J19 Figure 4.4. Typical DSC Test results for Polyester 19 A Unfilled + PEG-34 (50+50) Table 4.7. DSC Test Results for Different Polyester 19 A Unfilled + PEG-34 Blends. Energy Sr. No. Sample Temperature Absorption Range °C J/g 1 Polyester 19 A + PEG-34 (50+50) 21-40 46.49 2 Polyester 19 A + PEG-34 (65+35) 23-45 23.97 3 Polyester 19 A + PEG-34 (60+40) 22-43 19.05 4 ' Polyester 19 A + PEG-34 (70+30) 23-45 0.7 5 Epoxy 19 A + PEG-34 (80+20) 47.03 0.6 4.3.3.1.4 EC-439 Unfilled High Temperature Epoxy + PEG—34 At 50:50 weight ratio for this blend was quite homogenous, upon mixing; however, even after reduction of hardener content its premature hardemng caused 129 handling pr not very hi; 43.3.1.5 B T1 here is BP( was blende weight: suc introduced presented i also exhibi Polyester 1 results are handling problems during processing. The latent heat storage capacity of this blend was not very high (12 to 15 J/g) 4.3.3.1.5 Polyester 15-3 Micro Ultra Filler F lame-Retardant + PEG-34 This Polyester satisfies Boeing Specification: BMS-5—136 A. The hardener used here is BPO, which enhances the formation of cross-linking during curing. This material was blended with PEG-34 by shear mixing. The initial compositions used was 50: 50 by weight; success of this initial effort encouraged us to consider the compositions introduced in Table 4.8. All blends were highly homogenous, and the DSC test results are presented in Table 4.8 confirm their higher latent heat storage capacity. These blends also exhibited high level of strength, stiffness and temperature resistance. Therefore, Polyester 15-3: PEG34 blends were selected for further processing of formulations. The results are presented in next chapter. 130 Table 4 Sr. No. ~l b) Table 4.8. Flame Retardant Polyester: PEG-34 Blend Compositions and DSC Test Results. Energy Sr. No. Sample Designation Temperature absorption Range °C Hg 1 Flame Retardant + PEG-34 (65+35) +0.1% Fabroset 18-37 22 2 Flame Retardant + PEG-34 (65+35) +02% F abroset 16-38 20.5 3 Flame Retardant + PEG-34 (65+35) +0.3% Fabroset 18-39 23.97 4 Flame Retardant + PEG-34 (65+35) +0.4% Fabroset 20-35 23 5 Flame Retardant + PEG-34 (60+40) +0.1%Fabroset 19-37 25 6 Flame Retardant + PEG-34 (60+40) +0.2 F abroset 17-39 27 7 Flame Retardant + PEG-34 (60+40) +0.3 Fabroset 19-37 27 8 Flame Retardant + PEG-34 (60+40) +0.4 Fabroset 20-40 26 9 Flame Retardant + PEG-34 (60+40) +10%Glass 20-34 18.32 Fiber 10 Flame Retardant + PEG-34 (60+40) +15%Glass 20-39 25 Fiber 11 Flame Retardant + PEG-34 (75+25) +2% Glass 22-40 17 Fibers 12 Flame Retardant + PEG-34 (7 5+25) 2135 4-7 131 EXPEl 5.1 GENEI The fin retardant pl molding cc CHAPTER 5 EXPERIMENTAL RESULTS FOR FINAL POLYMER BLEND COMPOSITES 5 .1 GENERAL The final system discussed in this chapter is a blending of PEG-34 with flame retardant polyester 15-3, subjected to our selected compounding and compression molding conditions. 5.2 Sample Designations The final samples made and tested are listed below (all properties are by weight). a. Slab # F 1 - Flame Retardant (15-3) + PEG-34 (65+35)+ 5% Glass fibers + 2 % Hardener (BPO) Slab # F 1+2 - Flame Retardant (15-3) + PEG-34 (65+35)+ 5% Glass fibers + 2 % Hardener (BPO) (cast again) Slab # F2 - Flame Retardant (15-3) + PEG-34 (65+35)+ 10 % Glass fibers + 2 % Hardener (BPO) Slab # F3 - Flame Retardant (15-3) + PEG-34 (65+35)+ 20 % Glass fibers + 2 % Hardener (BPO) (not good slab) Slab # F3+1 - Flame Retardant (15-3) + PEG-34 (65+35)+20% Glass fibers + 2 % Hardener (BPO) Slab # F4 - Flame Retardant (15-3) + PEG-34 (65+35)+ No Fibers + 2 % Hardener (BPO) Slab # F5 - Flame Retardant (15-3) + PEG-34 (80+20)+ No Fibers + 2 % Hardener (BPO) 132 h. Slab # F6 - Flame Retardant (15-3) + PEG-34 (80+20)+ 5% Glass fibers + 2 % Hardener (BPO) i. Slab # F7 - Flame Retardant (15-3) + PEG-34 (80+20)+ 10 % Glass fibers + 2 % Hardener (BPO) j. Slab # F8 - Flame Retardant (15-3) + PEG-34 (80+20)+ 20 % Glass fibers + 2 % Hardener (BPO) k. Slab # F9 - Flame Retardant (15-3) + PEG-34 (65+35)+ 1 % Cellulose fibers + 2 % Hardener (BPO) l. Slab # F10 - Flame Retardant (15-3) + PEG-34 (65+35)+ 1.5 % Cellulose fibers + 2 % Hardener (BPO) m. Slab # F11 - Flame Retardant (15-3) + PEG-34 (80+20)+ l % Cellulose fibers + 2 % Hardener (BPO) n. Slab # F12 - Flame Retardant (15-3) + PEG-34 (80+20)+ 1.5 % Cellulose fibers + 2 % Hardener (BPO) These samples will be discussed in detail in the following paragraphs. 5.3 DISCUSSION OF RESULTS 5.3.1 Slab No F1 The mix design (by weight) for this slab is as follows. a. Flame Retardant 15-3 : PEG-34 (65+35) b. Glass Fibers 5% (by total weight) 0. Hardener = 2%(by total weight) PEG-34 was melted at 60°C before mixing it into the flame retardant polyester, the temperature of the mix was kept to be around 36°C. Flame retardant polyester was 133 measured in fibers were 1 minute. 1131 minutes. Th molding me of 48000 lb much soil 3 through the thickness tr 5.3.3 Slab l ‘ The mix de Mi resulted, I T110111 in CC SlBIained . c°mi-‘ressi 339318601 Specimm measured in a glass beaker of 2000 ml size and then PEG-34 was added into it. Glass fibers were then added and this mix was stirred with mechanical shear mixer for about 1 minute. Hardener was then added, and mixing started again and continued for 1 to 2 minutes. The mixed material was poured into the mold and taken to the compression- molding machine. The compression machine platens were already heated to 60°C. A load of 48000 lbs was applied to the mold, moving the plunger block inside. This sample was much soft and workable due to which the material escaped during application of load through the small gap between the plunger and wall. This resulted in reduction of thickness to less than 12mm (1/2”). Therefore, the slab was discarded. 5.3.2 Slab Fl+2 The mix design of this slab (by weight) is as follows. a. Flame Retardant 15-3 : PEG-34 (65+35) b. Glass Fibers 5% (by total weight) 2%(by total weight) c. Hardener Mixing was performed at 27°C (room temperature), and a homogenous blend resulted. The mixing time was 1-2 minutes, after which pouring into mold and fixing the mold in compression molding machine were done. The load of 213 KN was applied and sustained on the plunger for about 4-5 minutes, the mold was then removed from the compression machine, and the specimen was de—molded. The resultant slab had a satisfactory geometry, felt quite rigged and hard. The dimensions of the molding specimen was 305mm x 152mm x 12mm (12” x 6” x 1/2”) 134 The nithin the l The DSC ti Report 1 ‘ No. The density of the Slab was 1308 Kg/m3. The fibers were uniformly dispersed within the matrix. The Slab was without any flaws or cracks. 5.3.2.1 Investigations 5 .3 .2. l . 1 flermal Properti_es The DSC test results for this specimen are presented in Table 5 . 1. Table 5.1. Thermal Properties of Slab No. F 1+2 l 1 Energy _ Report Nomenclature Temperature Absorption Resistance to No. Range of J/g Elevated Energy Temperatures Absorption °C ‘1 Sample F 1+2-1 18-45 19.61 Stable at —l 200°C T Sample Fl+2-2 2040 23.85 Stable at 200°C l—TY Sample F 1+2-3 22-45 21.0 Stable at 200°C R Average 21.486 Stable at 1 200°C 1 \J 5.3.2.1.2 Water Absorption The water absorption of this specimen was negligible after 50 hours of immersion. 135 Ty 38. .4-29 r presented 5.3.2.1.3 Thermal Expansion Coefficient The thermal expansion coefficient test results are reported in Table 5.2. Table 5.2. Thermal Expansion coefficient of Slab F 1+2 or Report Sample ' um/m°C No. 1 Sample Fl+2-1 119 2 Sample F 1+2-2 107 3 Sample Fl+2-3 102 Ave Ave 109.3 5.3.2.1.4 Tensile Strength Tests Typical tensile stress-strain curves at 20°C and 350C are presented in Figures A- 28, A-29 respectively of Appendix A. The tensile strength results at 20°C and 35°C are presented in Table 5.3. 136 Table 5.3. Tensile Test Results for Slab F 1+2. At 20°C At 35°C Tensile % Tan. Sample Tensile % Tan. Strength Elongation Mod Nos. Strengt Elongation Mod psi ksi h psi ksi 57 4.15 5 Sample 39 6.18 4 Fl+2-1 61 5.6 4 Sample 43 6.78 3 F 1+2-2 68 6.01 4.5 Sample 50 8.05 2 Fl+2-3 62 5 .25 4.5 Ave 44 7 3 5.3.2.1.5 Environmental Scanning Electronic Microscopj The ESEM graph Shown in Figure 5.1 indicate that the fine PEG-34 particles are dispersed within the polymer matrix. This explains why melting of PEG-34 at elevated temperature does not cause substantial damage to mechanical properties of the blend. 137 53.3% Themdesig a. Fla b. 012 c. H34 Mixing resulted. The 11 mold in compr sutained on It. compression n‘ satisfactory gel S ‘ . i peclmen “as . Figure 5.1. ESEM Test Result of Slab with Glass Fibers 5.3.3 Slab No. F2 The mix design of this slab (by weight) is as follows. a. Flame Retardant 15-3 : PEG-34 (65+35) b. Glass Fibers = 10% (by total weight) c. Hardener = 2%(by total weight) Mixing was performed at 22°C (room temperature), and a homogenous blend resulted. The mixing time was 1-2 minutes, after which pouring into mold and fixing the mold in compression molding machine were done. The load of 213 KN was applied and sustained on the plunger for about 4—5 minutes, the mold was then removed from the compression machine, and the specimen was de-molded. The resultant slab had a satisfactory geometry, felt quite rigged and hard. The dimensions of the molding specimen was 305mm x 152mm x 12mm (12” x 6” x V2”) 138 The der within the man 5.3.3.1 lnvestit 5.33.1.1 Their ——— The DSC test I The density of the slab was 1390 Kg/m3. The fibers were uniformly dispersed within the matrix. The slab was without any flaws or cracks. 5.3.3.1 Investigations 5.3 .3. 1 .1 Thermal Properties The DSC test results for this specimen are presented in Table 5.4. Table 5 .4. Thermal Properties of Slab No. F2 Energy Report Nomenclature Temperature Absorption Resistance to No. Range of J/g Elevated Energy Temperatures Absorption °C T 1 Sample 172-1 2355 24.58 Stable at 200°C T 2 Sample F2-2 2040 23.85 Stable at 200°C 3 Sample F2-3 19-45 19.61 Stable at 200°C T Average 22.68 Stable at 200°C 5.3.3.1.2 Water Absorption The water absorption of this specimen was negligible after 50 hours of immersion. 5.3.3.1.3 Thermal Expansion Coefficient The thermal expansion coefficient test results are reported in Table 5.5. 139 53.3.1.4 h T§pic 30 and A-3l : are presented Table 5.5. Thermal Expansion Coefficient of Slab F2 or Report Sample um/m°C No. 1 Sample F2-1 83 2 Sample F 2-2 1 1 1 3 Sample F2-3 12 1 Ave Ave 1 05.0 5.3.3.1.4 Tensile Strength Tests Typical tensile stress-strain curves at 20°C and 35°C are presented in Figures A- 30 and A-31 respectively of Appendix A. The tensile strength results at 20°C and 35°C are presented in Table 5.6. 140 Tel ' Stre Table 5.6. Tensile Test Results for Slab F2 At 20°C At 35°C Tensile % Tan. Sample Tensile % Tan. Strength Elongation Mod Nos. Strength Elongation Mod psi ksi ' psi ksi 110 5.7 4 Sample 53 2.23 4 F 2-1 93 4 5 Sample 45 2.4 8 F 2-2 101 6.5 8 Sample 49 2.34 12 F2-3 101.3 5.4 5.6 Ave 49 2.4 8 5.3.3.1.5 Environmental Scanning Electronic Microscopy The ESEM graph shown in Figure 5.2 indicates that the fine PEG-34 particles are dispersed within the polymer matrix. This explains why melting of PEG-34 at elevated temperature does not cause substantial damage to mechanical properties of the blend. 141 5.3.4 Slab NC The mix desi a. Fl b. G c.H Mixil resulted. The l110lCl in C-Om 311315111160 on C01111316881011 satisfactory ; Specimen w; The . ”er r Figure 5.2. ESEM Test Result of Slab with Glass Fibers 5.3.4 Slab No. F3+1 The mix design of this slab (by weight) is as follows. a. Flame Retardant 15-3 : PEG-34 (65+35) b. Glass Fibers 20% (by total weight) 0. Hardener = 2%(by total weight) Mixing was performed at 27°C (room temperature), and a homogenous blend resulted. The mixing time was 1-2 minutes, after which pouring into mold and fixing the mold in compression molding machine were done. The load of 213 KN was applied and Sustained on the plunger for about 4—5 minutes, the mold was then removed from the compression machine, and the specimen was de-molded. The resultant slab had a satisfactory geometry, felt quite rigged and hard. The dimensions of the molding specimen was 305mm x 152mm x 12mm (12” x 6” x 1/2”) The density of the slab was 1402 Kg/m3. The fibers were uniformly dispersed within the matrix. The Slab was without any flaws or cracks. 142 53.4.1 lnvesti 53.4.1.1 m The DSC test 5.3.4.1.: E The water 211 5.34.1.3 Th. lire thermal 5.3.4.1 Investigations 5.3.4.1.] Thermal Properties The DSC test results for this specimen are presented in Table 5.7. Table 5.7. Thermal properties of Slab No. F3+1 Energy Report Nomenclature Temperature Absorpti Resistance to No. Range of on J/ g Elevated Energy Temperatures Absorption °C 1 Sample F 3+1-1 16-24 16.5 Stable at 200°C 2 Sample F 3+1-2 18-45 19.4 Stable at 200°C 3 Sample F 3+1-3 22-40 22.5 Stable at 200°C Average 19.4 Stable at 200°C 5 .3 .4. 1 .2 Water Absorption The water absorption of this specimen was negligible after 50 hours of immersion. 5.3.4.1.3 Thermal Expansion Coefficient The thermal expansion coefficient test results are reported in Table 5.8. 143 5.3.4.14 E T3pic 32 and A-33 are presenter Table 5.8. Thermal Expansion coefficient of Slab F3+1 or Report Sample um/m°C No. 1 Sample F3+1-1 68 2 Sample F3+1-2 86 3 Sample F3+1-3 108 Ave Ave 87.4 5.3.4.1.4 Tensile Strength Tests Typical tensile stress-strain curves at 20°C and 35°C are presented in Figures A- 32 and A-33 respectively of Appendix A. The tensile strength results at 20°C and 35°C are presented in Table 5.9. 144 Table 5.9. Tensile Test Results for Slab F 3+1 At 20°C At 35°C Tensile % Tan. Sample Tensile % Tan. Strengt Elongation Mod Nos. Strengt Elongation Mod h psi ksi h psi kSi 83 1.35 7 Sample 53 2.14 5 F3+1-1 81 3.25 6 Sample 47 3.0 5 F3+1-2 60 2.05 6 Sample 45 1.45 3 F3+1-3 74 2.21 6.4 Ave 48.4 2.2 4.4 5.3.4.1.5 Environmental SommLElectromc Microscopy The ESEM graph Shown in Figure 5.3 indicates that the fine PEG-34 particles are dispersed within the polymer matrix. This explains why melting of PEG—34 at elevated temperature does not cause substantial damage to mechanical properties of the blend. 145 5.3.5 Slab h —‘ The mix des Mix: resulted. Th mold ill QOH sustained or C0Illpressiol satisfactory SPeeirnen w The “1111111 th e n Figure 5.3. ESEM Test Result of Slab with Glass Fibers 5.3.5 Slab No. F4 The mix design of this slab (by weight) is as follows. a. Flame Retardant 15-3 : PEG-34 (65+35) b. Glass Fibers = Without Fiber 0. Hardener = 2%(by total weight) Mixing was performed at 23°C (room temperature), and a homogenous blend resulted. The mixing time was 1-2 minutes, after which pouring into mold and fixing the mold in compression molding machine were done. The load of 213 KN was applied and sustained on the plunger for about 4-5 minutes, the mold was then removed from the compression machine, and the specimen was de-molded. The resultant slab had a satisfactory geometry, felt quite rigged and hard. The dimensions of the molding specimen was 305mm x 152mm x 12mm (12” x 6” x 1/2”) The density of the slab was 1152 Kg/m3. The fibers were uniformly dispersed within the matrix. The slab was without any flaws or cracks. 146 yet-"‘35:: v '~ ‘ (J\ )——-l ET / g LJu K) J The DSC tes 5.3.5.1.: w; The water al 5.35.1.3. Th - The thermal 5.3.5.1 Investigations 5.3.5.1 .1 Thermal Properties The DSC test results for this specimen are presented in Table 5.10. Table 5 .10. Thermal properties of Slab No. F4 Energy Repor Nomenclature Temperature Absorption Resistance to t No. Range of Energy J/ g Elevated Absorption °C Temperatures 1 Sample F4-1 18-45 19.61 Stable at 200°C 2 Sample F4-2 21-40 21.35 Stable at 200°C 3 Sample F4-3 26-38 18.9 Stable at 200°C Average 59.8 Stable at 200°C 5.3.5.1 .2 Water Absorption The water absorption of this specimen was negligible after 50 hours of immersion. 5.3.5.1.3 Thermal Expansion Coefficient The thermal expansion coefficient test results are reported in Table 5.11. 147 53.5.1.4 E Typic 34 and A-35 are presented Table 5.11. Thermal Expansion coefficient of Slab F4 or Report Sample um/m°C No. 1 Sample F 4-1 62 2 Sample F4-2 79 3 Sample F4-3 67 Ave Ave 69.4 5.3.5.1.4 Tensile Strepgfir Tests Typical tensile stress-strain curves at 20°C and 35°C are presented in Figures A- 34 and A-35 respectively of Appendix A. The tensile strength results at 20°C and 35°C are presented in Table 5.12. 148 . Tensi Stren hps 53.5.1.5 Em The E dlspersed vii] leillperamre 1' Table 5.12. Tensile Test Results for Slab F4 1 At 20°C At 35°C _ Tensile % Tan. Sample Tensile % Tan. Strengt Elongation Mod ksi NOS. Strength Elongation Mod h psi psi ksi 81 12 1 Sample 31 6.72 21 F4-1 70 6 5 Sample 21 5 .28 2 F 4-2 80 5. 1 3 Sample 29 6.4 2 F4-3 77 7.7 3 Ave 27 6.13 8.3 5.3.5.1.5 Environmental Scanning Electronic Microscqpy The ESEM graph shown in Figure 5.4 indicates that the fine PEG-34 particles are dispersed within the polymer matrix. This explains why melting of PEG-34 at elevated temperature does not cause substantial damage to mechanical properties of the blend. 149 5 .6 Slab N ‘ (a) The mix des Mixi resulted. Th 111010 111 C011 31151311160 01 COlllpressiol SatiSfacton- SWilbert \\ Figure 5.4. ESEM Test Result of Slab with Glass Fibers 5.3.6 Slab No. F5 The mix design of this slab (by weight) is as follows. a. Flame Retardant 15-3 : PEG-34 (80+20) b. Glass Fibers = Without Fiber 0. Hardener = 2%(by total weight) Mixing was performed at 22°C (room temperature), and a homogenous blend resulted. The mixing time was 1-2 minutes, after which pouring into mold and fixing the mold in compression molding machine were done. The load of 213 KN was applied and sustained on the plunger for about 4-5 minutes, the mold was then removed from the compression machine, and the specimen was de-molded. The resultant slab had a satisfactory geometry, felt quite rigged and hard. The dimensions of the molding specimen was 305mm x 152mm x 12mm (12” x 6” x V2”) 150 The DSC test The density of the slab was 1152 Kg/m3. The fibers were uniformly dispersed within the matrix. The slab was without any flaws or cracks. 5.3.6.1 Investigations 5 .3 .6. 1 .1 Thermal Properties The DSC test results for this specimen are presented in Table 5.13. Table 5.13. Thermal Properties of Slab No. F5 Energy Repor Nomenclature Temperature Absorption Resistance to t No. Range of J/ g Elevated Energy Temperatures Absorption °C 1 Sample F 5-1 20-38 2.45 Stable at 200°C 2 Sample F 5-2 18-40 1.56 Stable at 200°C 3 Sample F5-3 23-45 9.35 Stable at 200°C T Average 4.45 Stable at 200°C 5.3.6.1 .2 Water Absorption The water absorption of this Specimen was negligible after 50 hours of immersion. 5.3.6.1.3 Thermal Expansion Coefficient The thermal expansion coefficient test results are reported in Table 5.14. 151 53.6.1.4 E Typic 36 and A-37 inTable 5.15 Table 5.14. Thermal Expansion coefficient of Slab F5 or Report Sample um/m°C No. 1 Sample F5-1 72 2 Sample F5-2 64 3 Sample F5-3 86 Ave Ave 74 5.3.6.1.4 Tensile Strength Tests Typical tensile stress-strain curves at 20°C and 35°C are presented in Figures A- 36 and A-37 of Appendix A. The tensile strength results at 20°C and 35°C are presented in Table 5.15. 152 . Tensile Strength psi dispersed wt limperamre Table 5.15. Tensile Test Results for Slab F5 At 20°C At 35°C Tensile % Tan. Sample Tensile % Tan. Strength Elongation Mod Nos. Strength psi Elongation Mod ksi psi ksi 173 13 16 Sample 109 10 4 F5-1 1 68 14 9 Sample 105 9 3 F 5-2 161 10 6 Sample 104 10 3 F5-3 167.4 12.3 10.3 Ave 106 9.6 3.4 5.3.6.1.5 Environmental Scanning Electronic Microscopy The ESEM graph shown in Figure 5.5 indicates that the fine PEG-34 particles are dispersed within the polymer matrix. This explains why melting of PEG-34 at elevated temperature does not cause substantial damage to mechanical properties of the blend. 153 5.3.7 Slab N —_— The mix des Mixi resulted. Th mold in con sustained 01. C0mpressior 331131381013- Sl‘ii‘lmeu w Figure 5.5. ESEM Test Result of Slab with Glass Fibers 5.3.7 Slab No. F6 The mix design of this slab (by weight) is as follows. a. Flame Retardant 15-3 : PEG-34 (80+20) b. Glass Fibers = 5%(by total weight) c. Hardener = 2%(by total weight) Mixing was performed at 27°C (room temperature), and a homogenous blend resulted. The mixing time was 1-2 minutes, after which pouring into mold and fixing the mold in compression molding machine were done. The load of 213 KN was applied and sustained on the plunger for about 4-5 minutes, the mold was then removed from the compression machine, and the specimen was de-molded. The resultant slab had a satisfactory geometry, felt quite rigged and hard. The dimensions of the molding specimen was 305mm x 152mm x 12mm (12” x 6” x 1/2”) 154 The density of the Slab was 1478 Kg/m3 . The fibers were uniformly dispersed within the matrix. The slab was without any flaws or cracks. 5.3.7.1 InvesLigltions 5.3.7. 1 .1 Thermal Properties The DSC test results for this specimen are presented in Table 5.16. Table 5.16. Thermal Properties of Slab No. F6 Energy Report Nomenclature Temperature Absorption Resistance to No. Range of J/g Elevated Energy Temperatures Absorption °C 1 Sample F 6-1 20-35 0.9 Stable at 200°C 2 Sample F 6-2 21-48 0.832 Stable at 200°C 3 Sample F6-3 19-40 0.7333 Stable at 200°C Average 0.822 Stable at 200°C 5 .3 .7. 1 .2 Water Absorption The water absorption of this specimen was negligible after 50 hours of immersion. 5.3.7.1.3 Thermal Expansion Coefficient The thermal expansion coefficient test results are reported in Table 5.17. 155 5.3.7.1.4 E T)pi 38 .4-39 res presented in Table 5.17. Thermal Expansion coefficient of Slab F6 or Report Sample um/m°C No. 1 Sample F 6-1 62 2 Sample F6-2 71 3 Sample F6-3 68 Ave Ave 67 5.3.7.1.4 Tensile Strenggh Tests Typical tensile stress-strain curves at 20°C and 35°C are presented in Figures A- 38 A-39 respectively of Appendix A. The tensile strength results at 20°C and 35°C are presented in Table 5.18. 156 ‘ Tensile l Strength psi 289 5.3.71.5 E1 The disPersed \‘ lempflamr Table 5.18. Tensile Test Results for Slab F6 At 20°C At 35 0C Tensile % Tan. Sample Tensile % Tan. Strength Elongation Mod NOS. Strength Elongation Mod ksi psi ksi psi 289 8 1 8 Sample 149 1 0 8 F6-1 226 6 13 Sample 157 9 9 F 6-2 249 6 12 Sample 127 4.5 6 F6-3 255 6.6 14.4 Ave 144.4 7.8 7.6 5.3.7.1.5 Environmental Scanning Electronic Microscopy The ESEM graph shown in Figure 5 .6 indicates that the fine PEG-34 particles are dispersed within the polymer matrix. This explains why melting of PEG-34 at elevated temperature does not cause substantial damage to mechanical properties of the blend. 157 5.3.8 m The mix de Mi: resulted. T mold in or SuStained . compressi Satisfactot 313601111611 TT within lhe Figure 5 .6. ESEM Test Result of Slab with Glass Fibers 5.3.8 Slab No. F7 The mix design of this slab (by weight) is as follows. a. Flame Retardant 15-3 : PEG-34 (80+20) b. Glass Fibers = 10%(by total weight) 0. Hardener = 2%(by total weight) Mixing was performed at 24°C (room temperature), and a homogenous blend resulted. The mixing time was 1-2 minutes, after which pouring into mold and fixing the mold in compression molding machine were done. The load of 213 KN was applied and sustained on the plunger for about 4-5 minutes, the mold was then removed fiom the compression machine, and the specimen was de-molded. The resultant slab had a satisfactory geometry, felt quite rigged and hard. The dimensions of the molding specimen was 305mm x 152mm x 12mm (12” x 6” x V2”) The density of the slab was 1382 Kg/m3. The fibers were uniformly dispersed Within the matrix. The slab was without any flaws or cracks. 158 _ ».‘m g“, j..’:'.+e,-jj- ' _ 5.3.8.1 Investigations 5.3.8.1 .1 Thermal Properties The DSC test results for this Specimen are presented in Table 5.19. Table 5.19. Thermal Properties of Slab No. F7 Energy Report Nomenclatur Temperature Range Absorptio Resistance to No. e of Energy n J / g Elevated Absorption °C Temperatures 1 Sample F 7-1 18-38 1.877 Stable at 200°C 2 Sample F 7-2 20-42 2.90 Stable at 200°C 3 Sample F 7-3 17-37 1.906 Stable at 200°C Average 2.22 Stable at 200°C 5 .3 .8. 1 .2 Water Absorption The water absorption of this Specimen was negligible after 50 hours of immersion. 5.3.8.1.3 Thermal Expansion Coefficient The thermal expansion coefficient test results are reported in Table 5.20. 159 1513 40.1141 re presented 11 Table 5.20. Thermal Expansion Coefficient of Slab F7 or Report Sample um/m°C No. 1 Sample F 7-1 71 2 Sample F7—2 75 3 Sample F 7-3 98 Ave Ave 81 .4 5.3.8.1.4 Tensile Strength Tests Typical tensile stress-strain curves at 20°C and 35°C are presented in Figures A- 40, A-41 respectively of Appendix A. The tensile strength results at 20°C and 35°C are presented in Table 5.21. 160 5.3.81.5. 1;: 111 dispersed l Table 5.21. Tensile Test Results for Slab F7 At 20°C At 35°C Tensile % Tan. Sampl Tensile % Tan. Strength Elongation Mod e NOS. Strength psi Elongation Mod ksi psi ksi 278 3 10 Sampl 153 4.4 25 e F 7-1 266 l 1 28 Sampl 152 5.2 15 e F7-2 222 5 36 Sampl 115 2.5 13 e F 7-3 256 6.4 24.6 Ave 140 4 14.4 5.3.8.1.5 Environmental Scanning Electronic Microscopy The ESEM graph Shown in Figure 5.7 indicates that the fine PEG-34 particles are dispersed within the polymer matrix. This explains why melting of PEG-34 at elevated temperature does not cause substantial damage to mechanical properties of the blend. 161 2‘ ‘1‘”? ‘W‘ _ 5.3.9 Slab N ‘. The mix des Mi) resulted. 11 111010 11] c0 S“Slanted 1' C0Ilrpressit satisfaclor SPs‘cimen ’ fiV'zi‘i ’r. . Figure 5.7. ESEM Test Result of Slab with Glass Fibers 5.3.9 Slab No. F8 The mix design of this slab (by weight) is as follows. a. Flame Retardant 15—3 : PEG-34 (80+20) b. Glass Fibers = 20%(by total weight) 0. Hardener = 2%(by total weight) Mixing was performed at 23°C (room temperature), and a homogenous blend resulted. The mixing time was 1-2 minutes, after which pouring into mold and fixing the mold in compression molding machine were done. The load of 213 KN was applied and sustained on the plunger for about 4-5 minutes, the mold was then removed from the compression machine, and the specimen was de-molded. The resultant slab had a satisfactory geometry, felt quite rigged and hard. The dimensions of the molding specimen was 305mm x 152mm x 12mm (12” x 6” x V2”) 162 Thed within the m: 5.391 lpygg 5.3.9.1.] _T_h_< The DSC tee Report ' The density of the slab was 1488 Kg/m3. The fibers were unifome dispersed within the matrix. The Slab was without any flaws or cracks. 5.3.9.1 Investi‘gtions 5.3.9.1 .1 Thermal Properties The DSC test results for this Specimen are presented in Table 5.22. Table 5.22. Thermal Properties of Slab No. F8 Energy Report Nomenclature Temperature Absorption Resistance to No. Range of J/ g Elevated Energy Temperatures Absorption °C 1 Sample F 8—1 18-38 2 Stable at 200°C 2 Sample F 8-2 21-40 1.9 Stable at 200°C 3 Sample F8-3 23-42 0.938 Stable at 200°C Average 1.613 Stable at 200°C 5 .3 .9. 1 .2 Water Absorption The water absorption of this Specimen was negligible after 50 hours of immersion. 5.3.9.1.3 Thermal Expansion Coefficient The thermal expansion coefficient test results are reported in Table 5.23. 163 5.3.91.4 1 Tit 42 and A4 are present Table 5.23. Thermal Expansion coefficient of Slab F8 or Report Sample um/m°C No. 1 Sample F 8-1 68 2 Sample F 8-2 71 3 Sample F8-3 65 Ave Ave 68 5.3.9.1.4 Tensile Strength Tests Typical tensile stress-strain curves at 20°C and 35°C are presented in Figures A- 42 and A-43 respectively of Appendix A. The tensile strength results at 20°C and 35°C are presented in Table 5.24. 164 Tensile Strengt l 1 l 1 psi dispersed lempefam Table 5.24. Tensile Test Results for Slab F8 At 20°C At 35°C Tensile % Tan. Sample Tensile % Tan. Strength Elongation Mod Nos. Strength Elongation Mod ksi psi ksi psi 210 4.5 20 Sample 168 2 11 F8-1 193 6.4 23 Sample 138 1.9 19 F 8-2 164 0.98 27 Sample 147 2.9 13 F8-3 189.3 3 23.7 Ave 151 2.26 14.3 5.3.9.1.5 Environmental Scanning Electronic Microscooj The ESEM graph Shown in Figure 5.8 indicates that the fine PEG-34 particles are dispersed within the polymer matrix. This explains why melting of PEG-34 at elevated temperature does not cause substantial damage to mechanical properties of the blend. 165 snow The mix design < a. F b.C of Mixing ‘ resulted. The 111 mold in compre sustained on thl compression m satisfactory get specimen was L Figure 5 .8. ESEM Test Result of Slab with Glass Fibers 5.3.10 Slab No. F9 The mix design of this slab (by weight) is as follows. a. Flame Retardant 15-3 : PEG-34 (65+35) b. Cellulose Fibers = 1%(by total weight) c. Hardener = 2%(by total weight) Mixing was performed at 26°C (room temperature), and a homogenous blend resulted. The mixing time was 1-2 minutes, after which pouring into mold and fixing the mold in compression molding machine were done. The load of 213 KN was applied and sustained on the plunger for about 4-5 minutes, the mold was then removed from the compression machine, and the specimen was de-molded. The resultant slab had a satisfactory geometry, felt quite rigged and hard. The dimensions of the molding specimen was 305mm x 152mm x 12mm ( 12” x 6” x V2”) 166 The dens within the matrii 5.3.10.1 1111:5112 5.3.10.1.1 [hep The DSC test re 5.3.10.1.351'31 The water abg 53.10.13 The The density of the slab was 1416 Kg/m3. The fibers were uniformly dispersed within the matrix. The Slab was without any flaws or cracks. 5.3.10.1 Investigations 5.3. 10.1.1 Thermal Properties The DSC test results for this specimen are presented in Table 5.25. Table 5.25. Thermal Properties of Slab No. F9 Energy Report Nomenclature Temperature Absorption Resistance to No. Range of Energy J/g Elevated Absorption °C Temperatures 1 Sample F9-1 25-43 22.5 Stable at 200°C 2 Sample F9-2 23-45 23.6 Stable at 200°C 3 Sample F9-3 18-40 19.85 Stable at 200°C Average 21.9 Stable at 200°C 5.3. 10.1 .2 Water Absorption The water absorption of this specimen was negligible after 50 hours of immersion. 5.3.10.1.3 Thermal Expansion Coefficient The thermal expansion coefficient test results are reported in Table 5.26. 167 5.3.10.1.4 @ Typical 44 and A45 re are presented 1: Table 5.26. Thermal Expansion coefficient of Slab F9 01 Report Sample um/m°C No. 1 Sample F 9-1 119 2 Sample F 9-2 121 3 Sample F9-3 102 Ave Ave 1 14 5.3.10.1.4 Tensile Strength Tests Typical tensile stress-strain curves at 20°C and 35°C are presented in Figures A- 44 and A-45 respectively of Appendix A. The tensile strength results at 20°C and 35°C are presented in Table 5.27. 168 5.3.10.1.5 m The ES dispersed wit) limperamre a Table 5.27. Tensile Test Results for Slab F9 At 20°C At 35°C Tensile % Tan. Sample Tensile % Tan. Strength Elongation Mod Nos. Strength Elongation Mod ksi psi ksi psi 77 7 5 Sample 56 3 .4 4 F 9- 1 107 7 10 Sample 53 2.42 4 F 9-2 115 4 1 1 Sample 47 3.21 3 F 9-3 99.6 6 8.6 Ave 52 9.03 3.7 5.3.10.1.5 Environmental Scanning Electronic Microscopy The ESEM graph shown in Figure 5.9 indicates that the fine PEG-34 particles are dispersed within the polymer matrix. This explains why melting of PEG-34 at elevated temperature does not cause substantial damage to mechanical properties of the blend. 169 . 3.3.11 Slab N0 § The mix desigr Mixing resulted. The I mold in comp sustained on t] compression 1' satisfactory gr specimen was Figure 5.9. ESEM Test Result of Slab with Glass Fibers 5.3.11 Slab No. F10 The mix design of this slab (by weight) is as follows. a. Flame Retardant 15-3 : PEG-34 (65+35) b. Cellulose Fibers = 1.5%(by total weight) 0. Hardener = 2%(by total weight) Mixing was performed at 23 °C (room temperature), and a homogenous blend resulted. The mixing time was 1-2 minutes, after which pouring into mold and fixing the mold in compression molding machine were done. The load of 213 KN was applied and sustained on the plunger for about 4-5 minutes, the mold was then removed from the compression machine, and the specimen was de-molded. The resultant slab had a satisfactory geometry, felt quite rigged and hard. The dimensions of the molding specimen was 305mm x 152mm x 12mm ( 12” x 6” x V2”) 170 The den withinthe malri 5.3.11.111113511 5.3.11.1.11_h_eL The DSC test ri The density of the slab was 1145 Kg/m3. The fibers were uniformly dispersed within the matrix. The Slab was without any flaws or cracks. 5.3.1 1.1 Investigations 5 .3. 1 1 .1 . 1 Thermal Properties The DSC test results for this specimen are presented in Table 5.28. Table 5.28. Thermal Properties of Slab No. F 10 Energy Repor Nomenclature Temperature Absorption Resistance to t No. Range of J/ g Elevated Energy Temperatures Absorption °C 1 Sample F10-1 20-40 23.33 Stable at 200°C 2 Sample F10-2 19-37 24.86 Stable at 200°C 3 Sample F10-3 23-45 19.98 Stable at 200°C Average 22.7 Stable at 200°C 5 .3.1 1 .1.2 Water Absorption The water absorption of this specimen was negligible after 50 hours of immersion. 171 53.111.311.91 The thermal eXT 5.3.11.1.4 E Typica 46 and A-47 rt are presented 1 5.3.1 1.1.3 Thermal Expansion Coefficient The thermal expansion coefficient test results are reported in Table 5.29. Table 5.29. Thermal Expansion Coefficient of Slab F10 or Report Sample um/m°C No. 1 Sample F10-1 107 2 Sample F10-2 125 3 Sample F10-3 115 Ave Ave 1 1 5 .6 5.3.11.1.4 Tensile Strength Tests Typical tensile stress-strain curves at 20°C and 35°C are presented in Figures A- 46 and A-47 respectively of Appendix A. The tensile strength results at 20°C and 35°C are presented in Table 5.30. 172 5.3.11.1.5 [ill The E are dispersed elevated temr blend. A Table 5.30. Tensile Test Results for Slab F 10 At 20°C At 35°C Tensile % Tan. Sample Tensile % Tan. Strength Elongation Mod Nos. Strength Elongation Mod ksi psi ksi psi 8 7 1 O 4 Sample 54 5 .32 3 F 1 0-1 84 8 6 Sample 64 1 3 2 F 10-2 86 12 4 Sample 5 8 6 3 F 10-3 85.6 10 4.6 Ave 58.6 8.1 2.6 5.3.11.1.5 Environmental Scanning Electronic Microscopy The ESEM graph shown in Figure 5 . 10 indicates that the fine PEG-34 particles are dispersed within the polymer matrix. This explains why melting of PEG-34 at elevated temperature does not cause substantial damage to mechanical properties of the blend. 173 The mix dCSigI Mixing resulted. The I mold in comp: slutained on d compression 1' satisfacton‘ gt specimen was Figure 5.10. ESEM Test Result of Slab with Glass Fibers 5.3.12 Slab No. F11 The mix design of this slab (by weight) is as follows. a. Flame Retardant 15-3 : PEG-34 (80+20) b. Cellulose Fibers = 1%(by total weight) c. Hardener = 2%(by total weight) Mixing was performed at 27°C (room temperature), and a homogenous blend resulted. The mixing time was 1-2 minutes, after which pouring into mold and fixing the mold in compression molding machine were done. The load of 213 KN was applied and sustained on the plunger for about 4-5 minutes, the mold was then removed from the compression machine, and the specimen was de—molded. The resultant slab had a satisfactory geometry, felt quite rigged and hard. The dimensions of the molding specimen was 305mm x 152mm x 12mm (12” x 6” x V2”) 174 The den withinthe matri 5.3.12.1 lilygsfi 5.3.12.1.1 1h}: The DSC test r: 1 Report ‘ Ni 1 No. 1 1 i\ l S: TTA‘S , 3 '1 l l l l l l l H | l l l 1 The density of the Slab was 1150 Kg/m3 . The fibers were unifome dispersed within the matrix. The slab was without any flaws or cracks. 5.3.12.1 Investigations 5.3.12.1.1 Thermal Properties The DSC test results for this specimen are presented in Table 5.31. Table 5.31. Thermal Properties of Slab No. F11 Energy Report Nomenclature Temperature Absorption Resistance to No. Range of J/g Elevated Energy Temperatures Absorption °C 1 Sample F11-1 20-38 0.5 Stable at 200°C 2 Sample F1 1-2 18-40 .9 Stable at 200°C 3 Sample F11-3 23-43 .738 Stable at 200°C Average 0.72 Stable at 200°C 5.3.12.1.2 Water Absorption The water absorption of this Specimen was negligible after 50 hours of immersion. 175 53.12.13 m The thermal 6X11 531214 E T}picaI 48 and A49 re are presented 1 5.3.12.1.3 Thermal Expansion Coefficient The thermal expansion coefficient test results are reported in Table 5.32. Table 5 .32. Thermal Expansion coefficient of Slab F 11 or Report Sample um/m°C No. 1 Sample F 1 1-1 93 2 Sample F 1 1-2 87 3 Sample F11-3 64 Ave Ave 81.3 5 3.12.1.4 Tensile Strength Tests Typical tensile stress-strain curves at 20°C and 35°C are presented in Figures A- 48 and A-49 respectively of Appendix A. The tensile strength results at 20°C and 35°C are presented in Table 5.33. 176 ”12. .—A 00 O )—‘ 00 CD 5.31215 E The E: a“ diSpersed elevated temp blend. Table 5.33. Tensile Test Results for Slab F 11 At 20°C At 35°C Tensile % Tan. Sample Tensile % Elongation Tan. Strength Elongation Mod NOS. Strength Mod psi ksi ' psi ksi 180 14 6 Sample 167 6 7 F l 1 -l 180 12 8 Sample 165 9.34 7 F 1 1-2 199 14 l 1 Sample 196 9.4 7 Fl 1 -3 186.4 13.4 8.3 Ave 176 8.24 7 5.3.12.1.5 Environmental Scanning Electronic Microscopy The ESEM graph shown in Figure 5.11 indicates that the fine PEG-34 particles are dispersed within the polymer matrix. This explains why melting of PEG-34 at elevated temperature does not cause substantial damage to mechanical properties of the blend. 177 5.3.13 SlabN The mix desig Mixir. resulted. The mold 111 C0111} “Stained 011 C01111316581011 satisfactory g Spetiolen wa Figure 5.11. ESEM Test Result of Slab with Glass Fibers 5.3.13 Slab No. F12 The mix design of this slab (by weight) is as follows. a. Flame Retardant 15-3 : PEG-34 (80+20) b. Cellulose Fibers = 1.5%(by total weight) c. Hardener = 2%(by total weight) Mixing was performed at 24°C (room temperature), and a homogenous blend resulted. The mixing time was 1-2 minutes, after which pouring into mold and fixing the mold in compression molding machine were done. The load of 21 3 KN was applied and sustained on the plunger for about 4-5 minutes, the mold was then removed from the compression machine, and the specimen was de-molded. The resultant slab had a satisfactory geometry, felt quite rigged and hard. The dimensions of the molding specimen was 305mm x 152mm x 12mm (12” x 6” x ‘5”) 178 The derr within the matri 5.3.12.1 lnvesti __—-—— 53.131.11th lheDSCtestrt l i 1 l Reportl h l No. l l l l l. l. 1 I C The density of the slab was 1143 Kg/m3. The fibers were uniformly dispersed within the matrix. The Slab was without any flaws or cracks. 5.3.13.1 Investigations 5.3.13.1.1 Thermal Properties The DSC test results for this specimen are presented in Table 5.34. Table 5.34. Thermal PrOperties of Slab No. F 12 Energy Report Nomenclature Temperature Absorption Resistance to No. Range of Energy J/ g Elevated Absorption °C Temperatures 1 Sample F 12-1 25-40 1.55 Stable at 200°C 2 Sample F 12-2 20-45 <1 Stable at 200°C 3 Sample F 12-3 18-37 1.35 Stable at 200°C Average 1.3 Stable at 200°C 5.3.13.1.2 Water Absorption The water absorption of this specimen was negligible after 50 hours of immersion. 5.3. 13. 1 .3 Thermal Expansion Coefficient The thermal expansion coefficient test results are reported in Table 5.35. 179 5.3.13.1.4 M T)pical 50 and A51 re are presented 1 Table 5.35. Thermal Expansion coefficient of Slab F 12 or Report Sample um/m°C No. 1 Sample F 12-1 87 2 Sample F12-2 106 3 Sample F12-3 69 Ave Ave 87.4 5.3.13.1.4 Tensile Strength Tests Typical tensile stress-strain curves at 20°C and 35°C are presented in Figures A- 50 and A-51 respectively of Appendix A. The tensile strength results at 20°C and 35°C are presented in Table 5.36. 180 Table 5.36. Tensile Test Results for Slab F 12 At 20°C At 3 5°C Tensile % Tan. Sample Tensile % Tan. Strength Elongation Mod NOS. Strengt Elongation Mod psi ksi h psi ksi 148 3 11 Sample 116 3.5 13 F12-1 183 12 7 Sample 150 5.2 8 F12-2 146 lo 18 Sample 153 5.1 5 F 12-3 159 8.3 12 Ave 139.6 4.6 8.6 5.3.13. 1 .5 Environmental Scanningfilectronic Microscopy The ESEM graph shown in Figure 5.12 indicates that the fine PEG-34 particles are dispersed within the polymer matrix. This explains why melting of PEG-34 at elevated temperature does not cause substantial damage to mechanical properties of the blend. 181 Figure 5.12. ESEM Test Result of Slab with Glass Fibers 182 COMPARAT. 6.1. A commerr system for corn investigation. I those of some 1 typical pohrne competitive ml 3M4i_ fihmmzi ELM—m, l%~—_,_ sues. In F"! 1m._nn CHAPTER 6 COMPARATIVE EVALUATION OF POLYMER BLEND COMPOSITES VERSUS GYPSUM BOARD 6.1. A commercial gypsum board suiting interior applications was used as the control system for comparative evaluation of the polymer blend composites developed in this investigation. Figure 6.1 compares the tensile stress-strain curves of gypsum board with those of some typical polymer blend composites. Figure 6.2 compares tensile strengths of typical polymer blend composites with that of gypsum board. These results confirm competitive mechanical performance of our polymer blend composites 1 300 -————-— fl _ .__: Gy—p—sum—Ban smea l l —F9 ! ——Seties4 Seriess I i__3°i$§* 1 Stress in Psi i o .x .rv'... ... r -v .ry .11 I4 .vH-t 1¥.I~'T'r-YT“-VVI>.<1ill..1-rtvlrr1' - rr-- ...r . 11.1 'Illll- .rr-- v-r.lr ..-r-vvvr- .. a e g» x 699"? ”To {969894969 5’9 ‘9 "b '19 ‘36” 6" Tobrpafig 65F 6943355 o9 'L 6’45 ago .42 93>": . . % K 09 Q. Q. Q. Q. Q. Q. Q. Q. Q 01 Q Q. 0. Figure 6.1. Tensile Stress-Strain Curves of Typical Blend Composites Versus Gypsum Board. 183 (psi) Tesile Strength figure 6.2. T The g'y Figure A-52 0 absorption wit Specific heat. f blend Compos themtal energ g 300 ——~——ee ——— —— 2 ’a‘ zoo ~ g 3' 100 - a 0 Fl § m E l.— Samples Type of Samples 13F1+2 IF2 mF3+1 lBF4 BFS IF6 IF? IFB IFQ BFtO BF11IF12 EGypsum Board Figure 6.2. Tensile Strength of Gypsum Board Vs. Typical Polymer Blend Composites. The gypsum board was also subjected to DSC tests, with the results shown in Figure A-52 of Appendix A. Gypsum board obviously did not exhibit any latent heat absorption within room temperature where its absorbed limited heat storage based on its specific heat. Figure 6.3 compares thermal energy absorption capacity of typical polymer blend composites with that of gypsum board. This Figure highlights the substantial thermal energy absorption capacity of our polymer blend composites. 184 Heat Energy Absorbed Jig 71 Final]: Renewable E1 blend compos bPical reside- Colorado) on results preger re(lilting enel 30T‘—— —m_——e _____ e __ 4 _m _ ,m_-_, - , 77 2511 —_l i— l. 3 O ---H ~—1 " '0 20 « f; 1 - . . o i e .0. 4,; 1 ; 1' .3 I Q .1 (74°45 l l l i 15 .l ng'x :.:.: :37} l | u ij 5:0:0: ‘tfia‘: l l ’2’ tote . 1 11.1 1 80:01 ‘2 o t I E 1° 1 is? Gypsum :55: e :55: i :1,\ Board ‘ vtotot ' t 00, ’0’.” 5‘ i.e. 0.9 20103 , 8°31 l l ' l Til 92:31 i l o t 1311111 4 '39" ~er Products 2 ["— _T___‘_—‘ T FLT—T"— T T i l l E F1 +2 35 El Polymer Composite 1 Cl Polymer Composite 2 Gypsum l | Figure 6.3. Thermal Energy Absorption Within room temperature ranges of Gypsum Board Versus Typical Polymer Blend Composites. Finally, in a study conducted by the US Department of Energy (National Renewable Energy Laboratory), the impact of replacing gypsum board with our polymer blend composite (65% Polyester + 35% PEG-34) for interior sheathing of walls in a typical residential building located in three climatic conditions (Michigan, Georgia and Colorado) on the building cooling and heating energy requirements was investigated. The results presented in Figure 6.4 confirms the value of our polymer blend composite in reducing energy loads on buildings. 185 °/oage Saving .4. [\J (.10 h 01 0) c: o C) O O O C) Cr EHt figure6.4. E) %age Saving Atlanta Lansing Pueble Geographic Locations 1 Cooling Energy I2 Heating Energy . Cooling Energy 1 3 Heating Energy m Cooling Energy E Heating Energy l l Figure6.4. Examples of energy saving resulting fiom replacement of gypsum board with polymer blend composite for sheathing of walls. 186 4L 1. 1t is feasible so that melting latent heat doe characteristics. 2. Reinforceml with proper pr. physical and 11 applications. 3. Polymer ble temperature pl temperature. 1 mechanical pr Perform dual 1 enhancing the 4- This resean latent heat sto mechanically accomlDlisltmt “uh slant-e1; ”013511163 CO] CHAPTER 7 CONCLUSIONS 1. It is feasible to finely disperse a low melt temperature thermoplastic within a thermoset so that melting of the thermOplastic upon temperature rise, which absorb substantial latent heat, does not lead to major loss of the blend physical and mechanical characteristics. 2. Reinforcement of blends of thermosets with finely dispersed thermoplastics together with proper processing of this composition yield polymer blend composites of desirable physical and mechanical characteristics and temperature resistance suiting building applications. 3. Polymer blend composites with thermoplastics having melt temperatures near room temperature provide substantial latent heat storage capacity within the comfort range of temperature. This heat storage is not accompanied with major loss of physical and mechanical properties upon temperature rise. Such polymer blend composites can thus perform dual roles as normal building components and also as a heat storage system for enhancing the energy-efficiency and comfort condition of buildings. 4. This research verified the feasibility of producing polymer blend composites with high latent heat storage capacity within room temperature, which is physically and mechanically competitive against gypsum board for sheathing applications. This accomplishment encourages formulation and processing of polymer blend composites with relatively high heat storage capacity, which offer high mechanical and physical properties comparable to those of plywood for structural paneling applications. 187 1. USA Energ http://wwwve 2. Dale E. Ma Second ed. 01 3. Robert S. S Knight and M 4. P. J. Flory; 5. BBC Educ: http://wwwal mar 2000. 6. D. C. Basse Cambridge, 1' 7. Macro gallt http://wwwps 8. M. 001, S, 904863 Mattinus Nijl. 10. M. M. C0 Polymer Blen “been UTEMm J“506486 13. R111 Dys 14. Taylor. G‘ meeediHas. 1 15-Hold.P,3 REFERENCES 1. USA Energy Department, “Country Analysis Briefs [online] Available http://www.eia.doe.gov/emeu.cabs.usa.htmo.27mar, 2000. 2. Dale E. Mans Perger, and Carson W. Pepper, “Plastics Problems and Processes” Second ed. October 1944, 1-39. 3. Robert S. Swanson, “Plastics Technology Basic Material and Processes” 1965 By Me Knight and Mc Knight Publishing Company, Pl7-119. 4. P. J. Flory; “Statistical Mechanics of Chain Molecules”, Interscience, New York, 1969. 5. BBC Education [online] Available at http://www.bbc.co.uk/scotland/revision/chemistry/materialsfromoil/plastics_rev.Shtml, 27 mar 2000. 6. D. C. Bassett; “Principles of Polymer Morphology”, Cambridge University Press, Cambridge, 1981. 7. Macro galleria, University of Southern Mississippi. [online], Available at http://www.psrc.usm.edu/macrog/floor3.htm, 3 January 2000. 8. M. Doi, S. F. Edwards; Claren Don Press, Oxford, 1988. 9. D. J. Walsh, J. S. Higgens A. “Polymer Blends and Mixtures” eds; A. Macomachie; Martinus Nijheff, Dordrecht, 1985. 10. M. M. Coleman, J. F. Graf, P. C. Painter, “Specific Interaction and the Miscibility of Polymer Blends”, Technomic Publishing, Lancaster, USA, 1991. 11. Fayt, R, Hadji and Reou, P. and Teyssie, P., J. Polym. Chem. Ed, 1985, 23, 337. 12. J. E. Mark, A. Eisenberg, W. W. Graessley, L. Mandelkem, E. T. Samulski, J.L.Koenig, G.D. Wignels; Polymer, 27, 483, 1986. 13. R.W. Dyson, “Engineering Polymers”, Blackie, Glasgow, 1990. 14. Taylor, G. I., “ The Formation of Emulsions in Definable Fields of Flow”, Proceedings, R. Soc., Vol. A146, 1934, PSI. 15. Hold, P., “Advances in Polymer Technology”, Vol. 4, 1984, 281 PP. 188 16. Elmerdorp Poly. Eng. 501 17. Meijer, H. Polymer Procr 18. Utracki, L Publications, 19. Folkes, M Applied Scier 20. Takayana; 16. Elmerdorp, J .J . and Maalke, R.J., “A Study on Polymer Blending Microrheology,” Poly. Eng. Sci, Vol. 25, 1985, p. 1041. 17. Meijer, H. E. H. and Janssen, J. M. H., “Mixing of Immiscible Liquids”, Progress in Polymer Proceeding Series, Vol. 4, 1991. 18. Utracki, L.A., “Polymer Alloys and Blends, Thermodynamics and Rheology,” Hanser Publications, 1990. 19. Folkes, M.J., “Proceeding, Structure and Properties of Block Copolymers,” Elsevier Applied Science Publishers, 1985. 20. Takayanagi, M., Mem. F ac. Engn., Kyushu Univ., Vol. 23, 1963. 189 APPENDIX A 190 Heat Flow (W/g) om oo 1 - -mmmoo 8.85 g .06 1 $.36 8.8.0 85.0 we .03 n .o 1 BER >L” UmO 8m” Wows: ow wmmbq - 38.0 -3825 1._ .m . _ . _ . H a _ .8 0 mo So Go N00 191 Heat Flow (W/g) ._.o 001 0.01 -00 1 14.01 .3 .NNOO 8.8.0 3.8 03 8.3.0 5.82%.“ Emca >1? UmO 80H ”00:: 0.». Homobm _ a _ 0 mo mmo 192 Heat Flow (W/g) O l wowwao 24.86 3.300 Lehman“ Ambaao 1._ 1 3x360 - 6.803 .m 1 3.800 L .mom<<\© - Emgm >19 Own 8% W85: ow mebm 1w _ . _ . _ a 4 _ . _ . -mo 0 mo 400 30 N00 Nmo 193 Heat Flow (W/g) 0.0 0.0 1 l Nosaao 80.26 001 -a.um.0//. . t - . _ 8.8.0 1 Namao L .0 1 1.. .m 1 - Ems?” >19 UmO 80" ”8:: cm 30101.0; 3.800 14.8055 1M0 _ . _ . _ . _ a _ . _ . _ . _ . 100 1N0 0 m0 A0 00 00 400 $0 194 Heat Flow (W/g) ._.0 0.01 0.01 10.0 l 4.01 14.01 00.80 30.86 _ 3.40.0 - 1 , 00.0500 Emca >19 Own 8% Wows: 0») meAK .380 5.0.0025 _ _ ‘ _ .. n J _ . _ a 5 M0 A0 00 m0 ._ 00 3.0 195 — low (17‘ 7(1) :1 at e a M00 0 A .. 0.MAOO 0 0 - o.mom0.:0 , .. 5.0.1.0 A 0.0m A8230 5 0.0»..0 U, lililtlllllllllliill " lltlllllllrlf‘ll m -0 A __ iwmaoa 0.3.0 -0 m -0 0 1.. 3050 >19 Own 8% W005: Om 2511.510 lOA . _ _ _ a 0 00 ‘00 30 ~00 196 Heat Flow (W/g) 4.0 0.0 1 0.0 1 10.0 1 330000103 mw.0AoO Ems?” >1$ U00 8m” ”8:: 0255513 N0 A0 00 00 :0 197 Heat Flow (W/g) o; 0.0 1 wm.NNoO -o; 1 2.8003 _ wm.o._ oO -o.m J - Emca >-mu Own Ham" Wows: ow EwEL m :00 _ _ . _ 0 mo 30 Go moo 198 Heat Flow (W/g) o; -041 -o.m 1 -00 1 -on Emca >-ou Own flow” ”8:: 0% waZ-: 8.86 8.3a mdwoo .omoo mod; 00 8.8003 8.800 8&6 .3 $925 Loo _ umo - d d 4 _ . _ . _ 0 mo So 30 moo mmo 199 0.0 .- :om- 3min >-_on Own ,womH News: Om ELEOA hammoo p.326 6.300 fibnoo N. «0% J No 50 00 mo 30 .30 200 Heat Flow (W/g) on . mmca i 7 En a2 was: 039-; Do 1 - $.36 b.8003 liltlltl nO.N 1 .0; 1 no.0 _ _ . _ a w _ -8 0 mo So So moo mmo 201 Heat Flow (W/g) ON a 05:8 >LN” UmO How” 28:: om 0703-8 0.0 I -0.M 1 mudooo 9000.06 0 8.300 3.3 0 8.8003 00.300 4.5.910 ._00.mNoO -0.04000<<\© IOL _ . _ . a a _ . -mo 0 mo 000 000 N00 202 Heat Flow (W/g) 30:8 313: 000 How” Wows: 0250-3 0 l mmbooo 30.9.5 - 00.800 wwmooo -1_ 1 -m 1 -0 1 mfmmoo - b.0856 1A _ . _ . _ a — . q . _ a _ .50 .N0 N0 A0 00 00 400 30 :0 203 Heat Flow (W/g) 30:8 29-3” 600 Ham“ Wows: owwmmbm 3.300 899:0 Aodmoo mmOAOO k: 356 100.00 0 _ _ _ a 0 LNmo N000 ammo 400.00 $Nmo 30.00 BNmo mmobo 204 Heat Flow (W/g) LL 30:8 >-_mn 000 018: W82: 2» EXT: 2 .300 améa 00.0000 8.86 -8856 _ .1 — 0 mo 300 N00 205 Heat Flow (W/g) 3m:8 >39 Own Homfi Wamcz om 009-0: 8.88 $8.86 0.01.090 00.9000 $0856 . _ 0 m0 A0 00 00 1_ 00 $0 30 -1 q —1 .4 — .1 — u- -1 u— q — - 206 Heat Flow (W/g) I ._L l I N I 30:8 31:” 000 108: W92: 05000-00 $800 38.85 00.0000 8.800 8.8226 0 . _ 0 00 ~00 207 Heat Flow (W/g) 010 a w w M., m _ L, 0 . J 30:8 >Lmn 600 08” W83: 0230-00 m on 1 _, , _- 3.0000 05 1, ../-1- 05040.06 0 11111111-- 00.0000 0 a _ .. ,- meow-03 0 3.30 1, H / 00.4000 // Iom AA.AWOO 1/1/ , 0.080556 // -00 1 \ -0 .0 1 / 0 - C -3 .N a _ . _ . _ . _ d _ J _ -00 0 00 A0 00 00 -_00 300 .338888 09 :0 208 Heat Flow (W/g) W 0 30:8 >00“ Own #8: ”8:: ow W>W00 . 0 O O 0M J . 0 w a 0 .. 0 1 .0 W 101M 1 _ 00.0400 . 1 @386 _ . 00.080 ' 00.0000 v 0 1 o 0 0.0 0.0000 00.00 0 _ 3.5800 -0.onwmo<<\0 n 0.0 _ . _ 4 _ 1 _ . A . A . A . _ .00 mo 50 00 00 ‘_00 50 30 30 338888 000 209 Heat Flow (W/g) Co _ M mmaa >8“ 80 a2. was: om 353 m -00 0 w -om - £006 @886 10%-W 1- @800 1 . 1 8.36 W 8.86 3.300 -00 1 58:25 -00 _ . _ . _ . _ _ a .8 0 mo So So moo 80 .338888 09 000 210 “ )1 .‘r 1A: f\1‘t C1135} 1‘ I 1 81F O 1 I 30:8 >307 500 How: Wag: 00 00-00 WM #05000 OLVNw-to V0580 .mo _ Egon emmm o: 8.200 .,. 8.800 -8 ., 3.800 /1] 5.03825 . 211 0 00 000 000 338888 09 Heat Flow (W/g) 0.0 0.01 10.Ml 10.5 1 -00 30:8 >00” U00 3% W82: 020208: 3: cave-woos 00.0300 0.3.0000 030.0000 B30003 .-AOo _ -00 00 A 00 .300 _ 000 000 212 Heat Flow (W/g) 0.00 -0.0M 1 10.05 1 -000 1 10.00 1 -0401 -0451 Emca >00“ Own fiwmfi Wows: om 35:0 Nbofioo 8.300 .\ meawoo N0000003 0.?» . $00 _ Amo N00 0‘ 0'1 O A O O _ -mo 4 Mmo 000 213 Heat Flow (W/g) 0N -0; 1 -00 1 -001 14.0 mubmoo Emcqo 310A“ UmO 01am” ”8:: ow 033:0 8.300 8.3003 N526 . mmobmoo 89302; mo 400 50 0 ~00 _ mmo 000 214 _ _ . B800 m, m w .1 M 0m 8800‘ 3.800 1 3.300 W W 0 m w W m. -N 1 F m M98003 Hm 1w 1 05:8 >9? Own Ham” Wows: omUOULo 3.300 #325 _ . _ _ _ ,1 _ . _ . _ 4 _ J 4 _ -mo 0 mo 8 mo mo So So :0 338888. 09 215 Heat Flow (W/g) ____..__...-_—._.._.~_,——_-. 11M-..__.. . o o 0 0. 5% >99 30 fig was: a, 35; 2 om w 1 ,1 0 _ .0 -3 4 M 0, M 1 .0 , 8.500 0 38,: -o m 1 ,. 3.3 o o Ewmfio . // . - {hmbmooe :NOLB o -1, 1 ENBOO 3.8 08.300 . $800 4 3V? 0 5.88926 / \«1 0. -1 ‘\ -oo 1 \\ 42.8003 \ 80800 ..\ 1 30.500 5.03856 10.3 _ _ . a d _ d _ . d .8 0 mo So So woo woo 338888 09 000 216 Heat Flow (W/g) O O ,W W W .3ch >13” UmO 06$ ”8:: cm 000 émx W W W W W W W W W W W W. 3.300 N885 -0 a 5.300 W ®.Vhoo I ANOOQV _.W 11‘ ml .36 MNWOOO 1 8.300 0.0000056 -05 1 W -00 A 1 _ 1 W . fl J .8 0 mo no mo mo 3388.86 09 W00 217 >_m._.z_ Umum 4m3m=¢ 432:0 3a 2328 4mm, 20 mono: 20 <65 ram .<_m_a Fufiama . 35.5 2% 5e 0.32330 .38. moan ax; Am: :8 06¢ mama< .835 mum.“ Wmmm Wu mp Poo Eimnmnorom <0 i. Stres 3 mo. wo1 ~01 3. Emma >101? H2520 Ham” 2.10:8 3+0 8 Neon Poo foo Noo mxnoanoa d Poo &. 8 who 218 >2. >95: Umum 4393 432:0 3n Emmmom 4mm» 20 230: 20 (gmxu ram (65 98:38 3:95 me romv Arcmgme 403. mean Q; .3: 2.8 095 mawa< «3&5 003. 33 mm :0 mQO Ea‘maaoroo 00” Hozmzo 010m" 9., 050 mm a moon Poo foo M. 00 who #00 mxnmanoa who who .000 220 )2. >042. 080 4c:m=¢ 482:0 3.1 3320.1... 4mm: 20 £25: 20 <55 rum <55 F3308 . 48% 2% 50 49526 E5508 42m. E30 25 4m: 28: Ema m:m6< 0300 :15 20 #0 wk; 30:8 >10 7 495:0 4mm” 04 050 mm m: 38 5:002:03: _<. >042. 080 4m:m=m 432:0 3.1 03028 4mm: 20 332.. 20 512 ram . 5% 98:38 4305 me .130 4310.25 982308 408. m_o:0 300 4% go: 08.0 m:o_10< wwmm 2000 n: 8 ram 5&0023033 100” 425:0 4am: om 030 00$ 8 01090 RM .1 m M 1m 0.00 o.no - d d a 0.8 0.00 0.00 2.00 ._.No 2.20 2.00 98:00: 222 >22 >043 080 40:02.0 482:0 34 1.00200 4002 20 3000: 2o :05 50 .. $05 900508 402020 esmx r000 40:02.0 E52308 422 mean 03 40: 2.8 091.0 m:040< “$00 2.: 0 20 KS 0.40 5100230300 <0 Ax. Stress 001 001 001 mm- no. a. 201 21120510 >100” 403:0 000: 210200 2110+. m: 0%0 0.00 5.00 93:020.: - 0.00 0.00 1.0.00 223 Alvi ASTM D638 Tensile Testing for Plastics Report No. 1603 Test Date 12-Apr-00 Operator Alvi Description F4-R W/O Fibers Sample No. F4—R W/O Fibers VENDOR Load Cell Capacity (Lbs) 100 Cross Head Speed (in/min) Preload Value (Lbs) 0.01 ' Yield Yield Tensile Tensile Total Elong Tan Mod Energy Spec ID Lbs (Lbs/lnSq) (Max Lbs) (Lbs/lnSq) (%) (Ksi) -R W/O Fib 27 81 12.15 1 Mean 27 81 12.15 1 Rel Std Dev % Sid Dev Maximum 27 81 12.15 1 Minimum 27 81 12.15 1 Range 0 0 0.00 0 Figure A-34: Tensile Test of Slab F4 at 20°C 224 >_<. >m._._s 0000 Hmzmze 4.80:0 3a 2302... Emma >09 fiwsmza 0.0m” om Ema E m: wmon 4mm” 20 980 522533 5 .3 wave: 20 38 3 - . 585 ram {55 P833 8 - .3306 me rcmv do 425.6 0.3358 m: 4.08. m_o:0 3.0 0.0.8. nu . \ .3: ion 30 4 mzoav. no L S a . 3 . m . o . . J . 0.00 0.00 ”.00 0.00 5.00 0.00 0.00 «.00 0.00 mxnmano: 225 >_<. >042. 0000 426.3 0.3030 3.. 2308 0.82 20 mono: Zo <53 ram . <65 08:39 425% 93x 580 .3305 0.033000 40$: E80 $0 .3: .58 09.0 mama: 00.3 300 mu 000 00.00 ._0 51005033 <0. 00 S tres s .N. 00 M00 0 .30 1 .30 - .30- 0N0 - 400- 00- 00. ~01 D 0.00 30:8 >00” 0.95:0 0.80 cmmEU mm m: 0000 a 0:00 0.00 0.00 0.00 40.00 3.00 3.00 40.00 mxamsmo: 226 ZS >m._._<_ 0000 0.88:8 0.30:0 won 3308 0.82 20 mmno: Zo 448:0 rum ”<55 0.3508 0.83:8 93x rumv 0.83:8 930308 138. m_o:0 Q0 .3: 2.8 060 mama: 0A: :04 00 400 40.00 510050.88 <8 00 Stress 400 i 400 1 00- 00- ~01 30:8 >00” 0.83:8 88m: ow 050 mm m: 0000 0.00 0.00 d ~«.00 0.00 0.00 020300: 40.00 40.00 40.00 227 >_0._._<_ 0000 dmzmze 4.30:0 qoq 3309... 0.8% 20 wave: 20 . <85 ram .585 9833 833.8 93x 55 0.85:8 P032000 .35. m_o:0 Q0 4m: :8 060 mamav. 0000 4.30 8.: N8 8.: a 51005033 00” 0.83:8 0.8: 8.. 050 mm m: 0000 0.00 d 4.00 d .- N.00 0.00 0.00 0.00 0.00 «.00 0.00 mxpmsno: 228 >_<. >0._._s 0000 0.28:8 0.30:0 3.. 3309... 48m: 20 wave: 20 $8.: ram «.8.: 0.8508 488.6 Azmx rcmv 48:28 0:32:08 .33.. m_o:0 3.0 .3: go: 060 m:8_.0< 8...: SB 00 .30 40.00 04 51003033 <8 i. Stres s 400 - :8. 400 .. 4001 no- 30:8 >00” 0.9508 0.9.: om 0E: 00 m: 00°C N00 5.00 0.00 0.00 40.00 4~.00 mxnm :no: 229 >_m._..<_ Umum 425:0 4323 3a 2328 Ems?” >k2” 133:0 a8” om was 3 a umoo Gian—50:: <0 .x. Ada Zo wfim 3o 1 mane: 20 3mm Sma rum \1\\\\({. ,, 3% F353 .3- \\ Hmsm=o esmx E5 3 425:0. 93:38 “mm 3° 1 4.03: maze Gav aka .3: :8 e9; Am 30 L mama; S 8 - a % no - o . . J . . . 98 +8 NS “.8 +8 30 98 mxnoano: 231 >2. .9de 08m Amsmzm Ammnmzm 3‘ 23:8 232 16:8 373” %a:m:o aamfi om 9% mm 8 Neon 59533038 __m4—s 0000 Hmamzw dams—6 3.. Emmzom 4mm” 2o «$00: 20 <65 ram <65 0.32308 ._.m=m=o Ame romv 432m 0.3258 .38. mono 30 Am: 2.8 060 mama: 0000 :00 mo 2m 9m: : Emcno >5? amaze 0:8” om MSU we 3 ~95 Elmaaoroa Poo 0.00 0.00 mxfiano: 234 >_m._._<_ 0000 Amam=m 0.32:0 3.. 2803. .230 2o 230: 20 <55 _.3 .320 P3258 . .333 me 58 33.6 0.35.68 .33. mean 0.3 4m: :8 06.8 m3m6< “3N0 :Nm Am 00 who .vlmnmaozoo <¢ Ax. Stress 00. 00- M0- .8- 30:8 >5? 0.03% 83” om 2% mo 8 .300 0.00 d 0.00 I: 900 n #00 N8 who @3033: 0.00 0.00 A. 00 Pmo 235 >_m._._s Umwm 425:0 Ammo—6 mow Emmzom AmflZo mono: 20 Sma ram 3% Easme amsm=m Azmx rumv $3.5 c.8238 422 mean GE 4m: .58 $66 mama< ”tho 4 umm Nd mm 93 .ua\ma.:o:aa L3” ‘Hosmzo glam” om momc 30 m: omen o. oo foo Poo Poo #00 who Poo floo mxnoanoz 237 >_<. >m4z. Doom 426.3 4356 3.. 23:8 4mm» 20 mmnon 20 . <55 rum <65 Famnzmnv 426:0 osmx ramv Fumzsma 403. mean 30v 4m: .58 $6.9 mama? 4mzm=m wwmm 4 40m 4N flow fifnw 3 .almnmsosom <¢ Ax. Stress Mao NS. 30. 481 Emca >5? 403:0 4n£ ow Ema m: a Mean Poo d Poo #60 who Poo mxfiauo: 4 8.8 3.00 3. oo 3.00 238 >_m4_<_ 03m 4m3m=m 432.6 34 2933.. 4mm.»Zo 380: 20 <55 ram <55 Arumzsmnv 426.5 93x Como 4215 chsmnv 42m. m_o:o ax; 4m: 5035c m2m6< wAmm 3N4 mm 23 m.wm Emaniorom 30” 495:0 4mm“ 04 Ema E H m: 300 98 Moo 4 u d _ Poo Poo 98 8.00 mxfio :no: 239 >_<. >m4_<_ Umum 426:5 43:46 34 23:8 Emca >-mou 425:5 45m» 04 £3 15 a moon 529.5033 (a fix. 4mm» 20 3mm ”8 . mono: 20 30¢ <55 rum :5 - <55 Fumzzmnv " 495.5 95x rumv mo :3 4255 93:58 So 42m. m_o=o ax; 3b» 48 . \ 4m: 505 fig 4 \< @543 :o 1 m ._8 - s 8 - 8 . 8 - no - o 4 q . . . . . 0.8 N8 3.8 woo 98 8.8 5.8 2.8 mxnoznos 240 >_m4z. 03m 425:5 4mmzso 34 23:8 4mm" 20 $30: 20 <55 :5 <55 9.82.68 45.5.5 95x .63 4255 35::an 42m. Econ 33 4m: 255 Axma mama< who.“ :Nm mm ..mm mom ~3ch >-m T 495:5 4am” ommgo 3 M m: 300 59633033 <5 Ax. Stres s .30 ¥ 3° 1 3o 1 So - 30. mo- No: .MO 1 Q5 3.0: 241 >_m4z_ 085 4535.5 455246 34 255255 Emca 51mm” 455:5 455" 04 055:3 woma m: M000 4555 25 84.5. 5:55.302: ,3 .x. mane: 20 :8 3 o <55 ram .<55 Arcflsmnv 8 1 . 45:55.5 osmx rcmv 5 45.5.5 F3363 my 495. Bone 33 0.55 8 . 45: 2.05 Ach on m256< .8 1 u s A 8 1 no 1 8 - o d d J Poo o. 3 oho 5.55 5.3 98 Pmo 0.45 0.50 mxnmzno: 242 627 I MLMLQQ 31fl9 \l | HICHIGQN STQTE . t. .rr;