”GERBER”!!! BoanmwombmmWncord. TOAVOIDFINESrdunonorbdmddom DATE DUE DATE DDE DATE DUE MSU I. An Affirmative 0 Inflation mm may ‘ OXYGEN TRANSPORT IN 80/20 NYLON 6/(61/6T), BLEND AT VARIOUS HUMIDITY VALUES BY Nat Pinitpongakul A THESIS Submittad to Hichigan stat. Uhivaraity in partial fulfillmant of tho raquiramants for the degraa of MASTER OF SCIENCE School of Packaging 1994 ABSTRACT OXYGEN TRANSPORT IN 80/20 NYLON 6/(6I/6T), BLEND AT VARIOUS HUMIDITY VARIOUS By Nat Pinitpongskul In general, the physical and barrier properties of polyamides are affected by the presence of water molecules within the polymer matrix. However, the effect of sorbed water on these properties can show different relationship such as the case of the totally amorphous Nylon 61/6T and semicrystallline Nylon-6. In this study, the blend of Nylon-6 and Nylon 6I/6T (80:20) was carried out to improve the barrier properties of Nylon-6. Sorption equilibrium isotherm and oxygen transport characteristics of the blend were studied as a function of water activity at 23°C. Data on the water sorption isotherm and oxygen transport on the blend at 23°C are presented. Permeability (P), solubility (S), and diffusion coefficient (D) have been determined as function of water activity for both mechanisms. The P, S, and D comparison of Nylon—6, Nylon 6I/6T, and the blend has been made. The differential scanning calorimetry method was used to determine crystallinity of the blend and to investigate the effect of water on the glass transition temperature of the blend. The effect of adding Nylon 6I/6T into Nylon—6 was found to exhibit strong interactive effects on oxygen barrier improvement. To my parents and family iii ACKNOWLEDGMENTS I would like to firstly a great deal of thanks and respect to Dr. Ruben Hernandez for his great guidance, support, encouragement and patience while serving as my major advisor. I would like also to express my appreciation to Dr. Susan Selke and Dr. Jame P. Lucas for serving on my committees and for their useful guidance and assistance. I am very grateful to Rafael Gavara for training, guiding, and teaching me how to operate the laboratory instrument and to solve some problems. I would like to thank Brain Ericson for teaching me to operate Differential Scanning Calorimeter over Composite Materials and Structures Center. I want also to knowledge the support recommend from MSU Research Excellence Project Funding. Next, I would like to thanks Takashi Urata for his kindness to let me take his time on Cahn Instrument. Also, I would like to express a lot of thanks to Supaporn Khuandee, Sorawit Narupiti, Natawut Nupairoj, Boonchoat Paosawatyanyong, and Chatphet Saipetch for their help and encouragement. Finally, I would like to express thanks and respect, from my heart, to my parents and all of my family. h! TABLE OF CONTENTS LIST OF TABLES LIST OF FIGURES INTRODUCTION LITERATURE REVIEW 2.1 Permeation Theory 2.2 Permeation Mechanism for Gases through Polymers 2. 2. 3 Variable Affecting Permeation Perability Measurements 2.4.1 Isostatic Method 2.4.2 Quasi-Isostatic Method Sorption Measurements 2.5.1 Polymer Film Studies Sorption Isotherm Models 2.6.1 Model for Polar Systems at High Solute Activities 2.6.2 Model for Gas Sorption in Glassy Polymers 2.6.3 Modified Dual Mode Sorption Model Polyamides 2.7.1 Nylon-6 2.7.2 Amorphous Nylon 2.7.3 Effect of Humidity on Nylon Crystallinity 2.8.1 Effect of Crystallinity on Properties Glass Transitions Page VII VIII 10 10 12 14 14 16 16 l7 17 19 20 21 23 24 26 26 2.10 Polymer Blends 2.10.1 Miscible and Immiscible Blends 2.10.2 Selecting a Polymer Combination 2.10.3 Previous Studies of Amorphous Nylon and Nylon-6 Blended MATERIAL AND METHODS Materials Methods EXPERIMENTAL ERROR Permeation Sorption RESULTS AND DISCUSSION Sorption Isotherm Equilibrium Sorption Isotherm Equilibrium Sorption Isotherm in closed containers with salt solution Oxygen Permeability Differential Scanning Calorimetry Method CONCLUSIONS APPENDIX APPENDIX A Computer Program for Flory-Huggins Model APPENDIX B Computer Program for Langmuir-Flory—Huggins Model APPENDIX C The Calculation Method of Weight Fraction APPENDIX D The Experimental and Known Values in each Plot of The Result and Discussion vi 3O 32 32 35 35 36 38 38 38 40 4O 4O 47 49 62 64 66 68 70 72 APPENDIX E APPENDIX F BIBLIOGRAPHY Data of Sorption isotherm tested by Cahn Electrobalance 74 Plot of The Sorption Isotherm Values Under Various Humidities tested by Cahn Electrobalance 94 95 vfi Table 1. The relationship between relative humidity and weight fraction 2. Langmuir and Flory-Huggins weight fraction contribution 3. K, B, and x parameter for water sorption in Nylon—6, Amorphous Nylon, and Amorphous Nylon/Nylon-6 at 23°C 4. Relative Humidity, Weight of samples after dry, weight of samples after condition, and weight fraction 5. Permeability (P), Solubility (S), and Diffusion Coefficient Values of Oxygen transport in polymer at 23° C 6. The Glass Transition Temperature, Melting Temperature, Enthalpy of Glass Transition Temperature and Melting Temperature, and % Crystallinity of the Blend 7. The Melting Temperature, Enthalpy, and % Crystallinity of Nylon-6 8. The calculation of weight fraction at steady state of various humidities 9. The total permeability values of Nylon blend, Nylon-6, and Amorphous Nylon 10. Fast diffusion coefficient values of Nylon blend, Nylon—6, and Amorphous Nylon 11. Total solubility coefficient values of Nylon blend, Nylon-6, LIST OF TABLES and Amorphous vfii Page 40 44 45 48 53 63 63 71 72 72 73 Table 12. 13. Sorption l4. Sorption 15. Sorption l6. Sorption 17. Sorption 18. Sorption 19. Sorption 20. Sorption isotherm isotherm isotherm isotherm isotherm isotherm isotherm isotherm values values values values values values values values x and sum of square values from from from from from from from from O to 3% RH 3 to 6% RH 6 to 13% RH 13 to 48% RH 48 to 55% RH 58 to 67% RH 67 to 75% RH 75 to 85% RH ix Page 73 74 75 76 78 79 83 86 91 LIST OF FIGURES Figure 1. 10. 11. 12. 13. Schematic of gas transport through film in which a represent the concentration of the permeant within the polymer at the interface Transmission rate profile curve by isostatic method Generalized transmission rate profile curve obtained by quasi-isostatic method of tests Typical Plot of Mt/M«,vs. tl/2 for sorption procedure Schematic illustration of rubber droplets dispersed in a continuous plastic phase Experiment sorption values and Langmuir—Flory—Huggins best fit Sum of squares versus x at 25°C Plot of water activity versus weight fraction distribution of sorption isotherm under various humidity model controlled by salt solution and measured by Cahn Instrument The typical plotted graph between 1/x and time of Nylon blend which it illustrated two mechanism of permeability Total oxygen permeability, fast and slow mechanism of Nylon blend at 23° C The permeability of Nylon-6, Amorphous Nylon, and Amorphous nylon/Nylon—6 (20:80) Fast and slow diffusion coefficient values of the nylon blend Total, fast, and slow mechanism solubility coefficient values of the blend at 23°C Page 10 13 15 29 42 43 46 50 54 56 58 14. The fast mechanism of diffusion coefficient of Nylon-6, Amorphous Nylon, and the blend 59 15. Total solubility of Nylon—6, Amorphous Nylon, and the blend 60 INTRODUCTION Polyamides are semi-crystalline or amorphous polymers and they are widely used in industrial and packaging applications. Polyamides are very moisture sensitive. This means that the presence of water has a significant effect on transport and mechanical properties (Ohashi, 1991). For example, nylon 6, one of the most common semicrystalline polyamides, has excellent mechanical properties, and relatively good gas barrier properties at dry conditions but decreasingly gas barrier properties at high relative humidity. Nylon 6I/6T is an amorphous polyamide that also shows a variation of permeability and mechanical properties with changing relative humidity. But, unlikely Nylon 6 , the oxygen permeability of amorphous nylon decreases as the humidity increases (Hernandez et al, 1992). Since these two polymers have different behaviors as a function of relative humidity, it is important to know the behavior of a blend of Nylon 6 and amorphous Nylon. In principle a blended polymer can be produced in which the effect of water on gas permeability may lie between the behavior of nylon-6 and of amorphous nylon. The goal of this research is to study the transport of oxygen , through a nylon blended film (80% Nylon 6 mixed with 20% amorphous Nylon) and to compare the results with the known behavior of each of the components respectively. Oxygen permeability, and water sorption isotherm were carried out at 23°C. An isostatic permeability method was used to measure the permeability of polymer film. The diffusion coefficient (D) of oxygen in the nylon blended film was also calculated by the method of Gavara and Hernandez (1993). Water sorption isotherms were determined by using a CAHN electrobalance. Differential scanning calorimetry (DSC) was used in this study to determine the glass transition temperature (T9) and percent crystallinity of Nylon blended at various relative humidities. The objectives of this study include: 1. To determine oxygen permeability of the Nylon-6/Nylon 6I/6T (80/20) blend at varying relative humidity at 23° C. From this experiment, the diffusion (D) and solubility coefficient (S) can be obtained. 2. To determine the water sorption isotherm of the blend at 23°C. 3. To evaluate the effect of humidity on glass transition temperature of Nylon blended by DSC method. 4. To compare these results with values available for pure Nylon 6 and amorphous Nylon. LI TERATURE REVIEW 2.1 PERMEATION TEEOR! The transport of a gas or vapor through polymeric films involves an activated diffusion process, in which three steps can be differentiated (Stannett and Yasuda, 1965): GAS {—- 0 C1 A C >C Film 1 2 Figure 1: Schematic of gas transport through film in which c represent the concentration of the permeant within the polymer at the interface. 1) Absorption of the permeating species into the polymer matrix at the high penetrant concentration surface, c1 indicated in figure 1. 2) Diffusion through the bulk of the polymer wall along a concentration gradient and toward the low concentration side c2. 3) Desorption from the surface at the lower concentration. Permeation of small molecular weight molecules through polymers is determined by the diffusion coefficient of the permeant species and the solubility coefficient of the permeant in the polymer. Diffusion of the permeant into the polymer films is driven by the concentration gradient of the permeant measured at both sides. Whereas, solubility is driven by the affinity of the permeant for the polymer (Imbalzane et al., 1991). Under steady state conditions, a gas or vapor will diffuse through a polymer at a constant rate, if a constant pressure difference and temperature are maintained across the polymer. The diffusive flux (J) of a permeant through polymer film can be defined as the amount of permeant passing through a plane or surface of unit area normal to the direction of flow during unit time as described by equation(1). .At (1) Where Q is the total amount volume of permeant passing through area A during time t. The relationship between the coefficient flux J and the concentration gradient is described by Fick's first law: Jz-D— (2) Where: D is the diffusion coefficient. dc/dx is the differential inherent in concentration of the permeant across the film over a differential thickness dx. The amount of permeant retained per unit volume of the film polymer (dJ/dx) is equal to the rate of change of concentration with time: £53 dr dt If Eq.(2) is substituted into Eq.(3) then: dc d1 (IL—DE] _ —dc dx dx (It and with rearrangement of the terms: dc 22253;] dt dx and 2 Ede—f dt dx (3) (4) (5) (6) Eq. (6) is a simplified form of Fick's second law of diffusion and applies in circumstances where diffusion is limited to the cross direction of the film and D is independent of concentration (Robertson, G.L., 1992). When the diffusion process reaches the steady state, J reaches a constant value if the concentrations cl and c2 are maintained constants. Eq.(2) can then be integrated across the total thickness of the film 1, and between the two concentrations, assuming D is constant and independent of concentration, then: Dc —c J: (1 2) (7) I By substituting for J using Eq. (1): Dc—c A! Q: (112) (8) When the permeant is a gas, it is easier to measure the vapor pressure (p), which is at equilibrium with the polymer, rather than the actual concentration ,c that is the concentration of permeant within the polymer. At sufficiently low concentrations, Henry's law applies and c can expressed as: c = Sp (9) Where S is the solubility coefficient of the permeant in the polymer. ::113CPV'F5)A1 I (10) Consequently, Q and rearranging equation (10), S=——Ql—— (11) At(Pl—p2) where P is the permeability constant. The steady state permeation of gases through a polymer is described by the permeability coefficient (P). The permeability coefficient (P) can be determined from direct measurement of the rate of transfer of a gas through a polymer or from the relationship of P = DS where D and S are separately determined (Crank and Park, 1968). There are seven assumptions made in the above simple treatment of permeation (Robertson, 1992). 1) The diffusion is at steady state condition. 2) Diffusion takes place in one direction only. 3) The concentration—distance relationship through the polymer is linear. 4) Both D and S are independent of the penetrant concentration. 5) Temperature is constant. 6) Henry's law applies. 7) Fick's law applies. Unlike the transport properties of non-reacting gases (e.g. oxygen and carbon dioxide), many organic liquids and vapors create non-ideal diffusion and solubility conditions (so called concentration—dependent). This behavior is due to the ability of the organic vapors to swell the polymer matrix and thus change the configuration of the polymer chains, which increases the rate of permeation (Hernandez et al., 1986). This behavior results in a concentration dependency of the permeability coefficient. 2.2 PERMEATION MECHANISM FOR GASES THROUGH POLYMERS Permeability is the steady state of transmission of a gas or vapor through a polymer film. During a permeability process, the gas or vapor dissolves in the material on one side or surface and diffuses through to the other side or surface by a molecular mechanism known as activated diffusion. Mass diffusional transport through polymers differs from a flow process such as Knudsen or Poiseuille flow that occurs through porous materials. The diffusion process is affected by the characteristics of the polymer, diffusant gases, the temperature and the relative humidity (Lebovitz, 1966). Molecular diffusion can take place because polymer chains have a random kinetic agitation or heat motion. The polymer chain segments have vibrational, rotational and translational motions that continually create temporary "holes" in the polymer matrix. The creation of these holes allows penetrant molecules to move through the polymer matrix under the influence of the concentration gradient. The amplitude and motion of the polymer molecules is directly related to the temperature, chemical composition and morphology of the polymer. The glass transition temperature (Tg) is an important factor for the mass transport of a penetrant-polymer system (Meares, 1954). The glass transition temperature marks the transition from a "glassy" polymer state to a "leathery" polymer state. This increased flexibility of the polymer is caused by the freezing of micro-brownian motion of polymer chain segments 20—50 carbon atoms in length (Boyer, 1977). This increase in polymer chain segmental mobility above the glass transition temperature corresponds with an increase in permeability and diffusion. The permeability of polymer is higher at a temperature above Tg than at a temperature below T9. 2.3 VARIABLES AFFECTING PERMEATION A board range of chemical and physical properties that affect permeation is as follows (Imbalzono et al., 1991): a) Ease of condensation of permeants Chemicals that readily condense will, therefore, permeate at higher rates. b) Intermolecular Chain Forces of the Polymer With higher intermolecular forces, the permeant molecules may not be able to overcome the inter-chain forces of attraction forces. As a result, as the intermolecular forces increase within the polymer, the permeability decreases. c) Crystallinity Higher levels of crystallinity pose a greater barrier to permeants, because the crystalline regions block molecular diffusion. Permeation takes place only in non-crystalline regions. d) Chemical Similarity Between Permeant and Polymer A given permeant will be more soluble in a polymer having a similar degree of polarity. This increases the solubility and permeation rate of the permeant. e) Molecule Size For an identical barrier layer, the smaller the permeant molecule, the faster the permeation. 2.4 PERNEABILITY MEASUREMENTS There are various methods for measuring permeability, which differ in terms of procedure and apparatus. In general, there are two basic test methods developed, which are referred to as the isostatic and quasi-isostatic techniques (Hernandez et a1, 1986). 2.4.1 Isostatic Mbthod A representative transmission rate profile curve for describing the transport of a permeant through a polymer membrane by an isostatic method is shown in Figure 2. From this type of experiment, diffusion coefficient (D) and permeability coefficient (P) values are obtained, and while the specific experimental arrangement may vary among investigators, the basic equations describing the permeation phenomenon are similar. 1.0 0.8 0.6 (mm, (NM). 0.4 0.2 1(1) 125 150 175 200 Themum) Figure 2: Transmission rate profile curve by isostatic method 11 A solution of Fick's first law, subject to boundary conditions of the experiment, was presented by Pasternak, et al. (1970) and is given as a first approximation in Equation (12). AM (3): 4 12 —12 7M) (EXZEY/z eXP(4Dt) (12) At .. where (AM/At)t and (AM/At)q,are the transmission rates of the penetrant at time (t) and at steady state, respectively, t is time and l is the thickness of the film. For each value of (AM/At)t and (AM/At)m,a value of 12/4Dt can be calculated from equation (2). By plotting (4Dt/12) as a function time, a straight line is obtained. From the slope of this graph, D is calculated by substitution in Equation (13). 2 D : (slope)! (13) 4 Smith and Adams (1981) used this method to study the effect of tensile deformation on gas permeability in glassy polymers. 12 02— (14) 7.199t0'5 where t0.5 is the time required to reach a rate of transmission 12 (AM/At)t equal to half the steady state (AM/At)oo value. DeLassus (1985) applied Equation (14) to calculate the diffusion coefficient of limonene vapor for different polymer films typically used for food packaging. The permeability coefficient (P) can be determined from the isostatic method by substitution into Equation (15). P ___ aGfl Ab (15) where: a = calibration factor to convert detector response to units of mass of permeant/unit of volume[(mass/volume)/signal units] G = response units from detector output at steady state (signal units) f = flow rate of sweep gas conveying penetrant to detector (volume/time) A = area of the film exposed to permeant in the permeability cell (area units) 1 = film thickness (thickness units) b = driving force given by the concentration or partial pressure gradient (pressure or concentration units) 2.4.2 Quasi-Isostatic Mbthod In this method, the permeated gas or vapor is accumulated and monitored as a function of time. A generalized transmission rate profile curve describing the transport of a permeant through a polymer membrane by the quasi—isostatic method is shown in Figure 2. As shown, the total l3 quantity of penetrant transmitted through the film is plotted as a function of time. Barrer (1939) presented a solution of Equation (5) for this specific set of experimental conditions, which allowed determination of D, the diffusion coefficient (Hernandez, 1986). 2 D-1 _— (16) 66 where: 9 is the intersection of the steady-state portion of the transmission curve (see Figure 3) and is called the lag time. 40 8 E .. E E 20 3 Sm(M)-On-OuantWa 0 10 0 15 30 45 .0 75 +——o | ime Figure 3: Generalized transmission rate profile curve obtained by quasi- isostatic method of test The steady state permeability coefficient (P) can be determined from the quasi-isostatic method by substitution into Equation (17). I P=L <17) Ab where: y = the slope of the straight line portion of the transmission rate curve (mass/time) 14 l = thickness of the film A = area of the film exposed to the permeant in the permeant in the permeability cell b = driving force given by the concentration or partial pressure gradient By plotting log [t1/2(AM/At)t] as a function of 1/t, it is possible to obtain information about the concentration dependency of the diffusion coefficient (D)(Meares, 1965). 2.5 SORPTION MEASUREMENTS 2.5.1 Polymer Film.8tudiea Sorption experiments are usually carried out at equilibrium vapor pressure, using a gravimetric technique in an apparatus that records continually the gain or loss of weight by a test specimen as a function of time. A recording electrobalance (Cahn Instrument Co., Cerritos, California) is commonly used for such studies. The diffusion equation appropriate for the sorption of penetrant by a polymer sample in sheet or film form was described by Crank (1975) as: M, 8 °° 1 —D(2m+ 1)2 7131 2 exp{ 12 } (18) M n2 ":0 (2m +1)2 m where RQ is the total amount of vapor absorbed by the sheet at time t, andM3° the equilibrium sorption attained theoretically after infinite time; t is the time to attain Mt and l is the thickness of the film sample. The application of Eq. (18) is based on the assumption that immediately the sheet is placed in the vapor, the concentration at each 15 surface attains a value corresponding to the equilibrium uptake for the vapor pressure existing, and remains constant afterwards. The sheet is considered to be initially free of vapor. The value of t/l2 for which Mt/Mm,=l/2, conveniently written (t/12)1/2 is given by (L) —___1_ln _”_2__l It: 9 (19) 12 g’ 7221) 16 916 The sorption diffusion coefficient (DS) can be calculated from Equation 18 by setting Mf/Mw equal to 0.5 and solving to give D5. 2 D = 0.0491 3 (20) Q5 where t0_5 is the "half-sorption time" or the time required to attain the value, ME/M&=O.5. 03'- 0.7 '- 0.6)- 0.‘ '- OJ)- 0.) *- 0“ A A A A AL :00 no 230 no Tmmrz (second-“10) Figure 4: Typical Plot of Mt/M«,vs. tl/2 for Sorption Procedure A generalized graphical representation of Equation (19) is shown in Figure 4, where values of Mi/Mn are plotted as a function of the square root of time (tl/Z). Thus, the value of t0.5 can be obtained graphically. l6 2. 6 Sorption Isotherm Models 2.6.1 Mbdela for polar systems at high solute activities Solutes sorbed at temperatures below their boiling point (such as organic solvents and water at room temperature) may not obey simple, ideal phase equilibrium relations such as Henry's law. For these cases, eqn. (19) does not describe the data well over the activity range, 0 18 where ’5”? refers to the Flory-Huggins contribution to the solute volume fraction and.)fiL refers to the Langmuir contribution. Since the equation (21) is nonlinear, it is convenient to determine the value for )6”? by numeric methods, such as the Newton-Raphson technique and eqn. (23) became (Ohashi, 1991): Ka V =FH , +———‘- 24) 1 (a1 2’) 1+Ba, ( The Langmuir equation is used to calculate the volume fraction of chemisorbed solute and the Flory-Huggins equation is used instead of Henry's law to calculate the volume fraction of water which is not chemisorbed. This model used along with a modified dual-mode sorption model represents the sorption of water vapor by an amorphous polyamide at 23°C. 19 2.7 POLYAMIDES Polyamides or nylons are very important industrial polymers. Polyamides incorporate in the backbone chain of the amide function: 0:0 1-2 Early development of nylons were in textile fiber applications. Polyhexamethyleneadipamide, nylon 6,6 [-NH(CH2)6NHCO(CH2)4CO-], the first truly synthetic fiber, was developed by W.C.Carothers synthesized in the early 19308 (Seymour, 1990). Nylons have been used commercially for packaging film applications since the late 19503 (Robertson, 1992). Polyamides are linear condensation products characterized by repeating groups such as Rz-CONH-Rl. The various types of nylons differ by the chemical structure of segments R1 and R2 that separate adjacent amide groups (Turbridy and Sibilia, 1986). The first nylons were made by condensing a di-acid with a di-amine. They were characterized by the number of carbon atoms in the parent compounds. H,N(CH 2),, NH 2 + H00C (CH 2)_,_,C00H ——+ NH (CH 2),,NHC0 (CH 2)Hco + H20 diamine dibasic acid nylon-mm H2N(CH 2),_,C00H ——. NH (CH 2)Hco + H20 amino nylon-n 0' (T 20 Later methods were developed for the manufacture of nylons by condensation of certain amino acids which contain both the groups (-COOH and NHZ), which condense to eliminate water. These nylons are characterized by the use of a single number derived from the number of carbon atoms in the parent molecule. Thus, poly(caprolactam) based on a six carbon molecule is nylon 6 and poly(aminodecanoic acid) with eleven carbons is known as nylon 11 (Robertson, 1992). In general, they offer clarity , thermoformability, high strength and toughness over a broad temperature range, chemical resistance as well as barrier to gases, oils, fats and aromas. Biaxial orientation of nylon films is believed to improve flex-crack resistance, mechanical and barrier properties (Turbridy and Sibilia, 1986). 2.7.1 nylon-6 Nylon 6, which was produced by P. Schlack in 1937, is made by the anionic polymerization of s-caprolactam (Seymour, 1990). This engineering polymer is used in the U.S. for packaging applications because of its balance of cost, physical properties and process conditions. Nylon-6 possesses high temperature, grease and oil resistance. For blown and cast extrusion, as well as cast coextrusion, nylon 6 resins are favored by most converters. When used as a component of multilayer polyolefin films, these nylons enhance properties such as barrier and high temperature sealability and yet maintain the excellent toughness of the polyolefins (Blatz, 1989). Application For most packaging applications, nylons are combined with other materials that add moisture barrier and heat sealability, such as LDPE, ionomer, ethylene vinyl acetate (EVA) and ethylene-acrylic acid (EAA). Nylon films have been used mostly in food packaging such as vacuum packaging, boil-in bag packs and the packaging of surgical equipment for steam sterilization (Briston, 1986 and Turbridy and Sibilia, 1986). Medical packaging applications, such as packaging of hypodermics and other medical devices, are a relatively new and expanding area for the nylons. Their toughness, puncture resistance, impact strength, abrasion resistance and temperature stability make nylons suitable for protecting sterile devices during shipping and storage. Modified-nylon resins have recently been introduced that permit radiation sterilization (Turbridy and Sibilia, 1986). 2.7.2 Amorphous Nylon (Salar® PA) Dupont has developed a series of barrier resins under the Selar trade mark to serve the needs of the market place for all types of packaging applications. Selar®>PA, a co-polymer of Hexamethylene isophthalamide and terphthalamide, is an amorphous polyamide which can be used as the barrier in both monolayer and multilayer packages for specialty chemicals, cosmetics, and certain dry foods at present, with potential for a wide variety of food applications. IQ L) g * COZH + ”Swen-Cw 09H 02H 70% 30% Isophthalic acid Terephthalic acid Amorphous Nylon Since the acid isomers are randomly placed into the polymer backbone, resulting in structural irregularity, no crystallization of the polymer matrix was observed. No evidence of crystalline melting point is found, by performing differential scanning calorimeter (DSC) analysis. In general, properties of Nylon 6I/6T can be summarized the following; -Nylon 61/6T is a resin with a good combination of glass-like clarity, good barrier properties, and processing versatility. It has good mechanical and barrier properties in the presence of moisture and therefore does not have to be protected from exposure to high humidities as do other nylons. -Second generation SelarC>PA.resins are under development which will have improved solvent resistance, barrier, durability, and high temperature capability. Application SelarC>PA.is being considered for a variety of packaging applications. Its glass-like clarity with its barrier makes SelaflO PA considered to be a material of choice for products such as shampoo, cosmetics, household products, and dry foods replacing small glass containers. In addition, because of its properties including excellent processibility, Selar®>PA.is also used in packaging applications such as monolayer blow molded bottles or thermoformed containers. Developments are now underway for using the resin in flexible multilayer films for meat wrap, cereal liner and bags for snack foods. However, according to FDA regulations, the SelarC>PA resin has not been approved for direct food contact. The application of Selar®>PA.is thus either a barrier layer or the outside layer where its glassy and transparent qualities give the containers an attractive appearance (Blatz, 1992). 2.7.3 Effect of Humidity on nylon Nylons are hydrophilic materials and therefore they are moisture sensitive, due to susceptible formation of hydrogen bonds with water. The absorbed moisture acts as a plasticizer in the polymer matrix. As a result, barrier and mechanical properties are noticeably affected. Because of the presence of the hydrophilic amide group, all nylons are affected by moisture, but these effects decrease as one goes from nylon 6 to nylon 12, or nylon 6,6 to nylon 6,12 because the ratio of hydrocarbon to amide groups increases. Thus, while nylon 6 and nylon 6,6 undergo a dimensional change of about 0.65 percent at 50 percent relative humidity, nylon 11 and 12 undergo a dimensional change of about 0.10 percent under these conditions. 24 The volume resistivity decreases and the dielectric constant increases as the percent humidity increases, and these effects are greatest for nylon 6 and nylon 6,6 and least for nylon 11 and nylon 12. The dielectric constant at 50 percent humidity increases as follows: nylon 6, nylon 6,6, nylon 11, and nylon 12 (Seymour, 1990). The effect of crystallinity on the equilibrium water absorption of nylons was reported by Starkweather et al.( 1973). Lowering the amide group concentration and the relative humidity diminishes the effect of a change in crystallinity. 2.8 CRYSTALLINITY Symmetrical, hydrogen-bonded, linear polyamides are invariably highly crystalline and owe their excellent mechanical behavior to this property. Yield point, tensile strength, elastic and shear module, hardness, and abrasion resistance increase with increasing crystallinity, whereas moisture absorption and impact strength drop slightly (Mark, 1969). A number of "crystallinity" is often used as a measure of the degree of crystalline order in semicrystalline polymers. The term implies the presence of a two-phase system of crystalline and amorphous regions. This was a reasonable interpretation of the diffraction patterns of such polymers as polyethylene and polytetrafluoroethylene. Diffraction from these polymers resembles the superposition of a crystalline diffraction pattern on an amorphous pattern, which in turn appears to be an extrapolation of the diffraction pattern of the melt (Clark and Wilson, 1973). For all the nylons there is no obvious 25 procedure for resolution of a diffraction pattern into crystalline and amorphous regions and the calculation of even an empirical degree of crystallinity. There is no obvious demarcation between crystalline and amorphous areas. An instrument such as the Du Pont 310 curve analyzer can be used to resolve these patterns but the results can be quite arbitrary. Thus for polyamides, x-ray diffraction is not commonly used to derive a measurement of crystallinity. The usual methods for assessment of degree of crystallinity in nylons are by measurement of density or by infrared techniques. Measurement of density is perhaps most satisfactory because it is rapid, precise, and unaffected by sample orientation and geometry. It is not an absolute method, however, and requires calibration - the assumption of amorphous and crystalline densities. It also requires close control over water content. Ideally, the samples to be compared should be dry. The plasticizing effect of water on a dry sample of low crystallinity may increase its crystallinity. It should also be realized that massive samples are typically not uniform in crystallinity (Kohan, 1973). The differential scanning calorimetry method for determining the percent crystallinity of a semicrystallinity polymer is based on the measurement of the heat of fusion, AHf, and the reasonable assumption that this quantity is proportional to the percent crystallinity (Wunderlich and Cromier, 1967). The percent crystallinity may be calculated from: . . AH , %Crystallzmty = AH. (2 5) f 26 Where AHf* is the heat of fusion for a hypothetical 100% crystalline sample. For nylon—6, AHf* is 195 J/g (Brandrup and Immergut, 1991). 2.8.1 Effect of Crystallinity on Properties The effect of crystallinity on the properties of nylons is substantially the same as it is for other semicrystalline polymers. Modulus and strength and related properties such as hardness and yield point increase with increasing crystallinity. Measures of toughness such as impact strength decrease, particularly in the high-crystallinity range. However, the effect of crystallinity can hardly be discussed independent of that of water. The properties of polyamides are as dependent on water content as they are upon crystallinity. Not only can water have an effect on crystallinity, but it also changes physical properties independently. Once a sample has absorbed a given amount of water at any temperature, this water can be removed and replaced at this temperature without noticeable effect on crystallinity, but the effects on properties will be substantial. Water acts as a plasticizer for nylons and lowers the glass transition and the characteristic temperature of mechanical relaxation. 2.9 GLASS TRANSITIONS Most polymers are either completely amorphous or have an amorphous -like component even if they are crystalline. Such materials are hard, rigid glasses below a fairly sharply defined temperature known as the glass transition temperature Tg. At temperatures above the glass transition temperature, at least at slow to moderate rates of 27 deformation, the amorphous polymer is soft and flexible and is either an elastomer or a very viscous liquid. Mechanical properties show profound changes in the region of the glass transition. Many other physical properties change rapidly with temperature in the glass transition region. These properties include coefficients of thermal expansion, heat capacity, refractive index, mechanical damping, nuclear magnetic resonance behavior, and electrical properties. The importance of the glass transition temperature, Tg, in the mass transport of penetrant polymer systems was described by Meares (1954), and is now very well recognized. The glass transition temperature of any amorphous substance, whether polymeric or not, is defined as the point where the thermal expansion coefficient undergoes a discontinuity. In polymers, there may more than one discontinuity in the thermal expansion coefficient. The largest discontinuity is usually associated with the loss of the molecular mobility which permits configurational rearrangements of the chain backbones. A number of physical properties, such as thermal and electrical conductivity, optical properties, chemical luminance, fluorescence and gas permeability are affected significantly by transitions. The effect of T? on gas permeability is of considerable practical importance since a large number of polymeric systems are used as coatings or protective materials in the form of paint or plastic film (Bear, 1964). The sorption of gases above Tg indicates that the heat of solution must include along with the heat of interaction between the diffusant and polymer, the energy for separating the polymer chains which is endothermic, therefore accounting for the endothermic and slightly 28 exothermic heat of solution. The exothermic heat of solution below Tg can be explained by the inclusion of the exothermic heat of adsorption for the "hole filling" in the heat of solution. The diffusion process above Tg requires a larger zone of chain activation than below Tg which is consistent with the higher surge of activation reported above Tg (Hopfenberg and Stannet, 1973). The glass transition temperature is generally measured by experiments which correspond to a time scale of seconds or minutes. If the experiments are done more rapidly so that the time scale is shorted, the apparent Tg is raised (Nielson, 1974). Blatz (1989) had measured the glass transition temperature of nylon-6 by using differential scanning calorimetry (DSC). However, no glass transition temperature could be determined for the nylon-6 because it is probably hidden in the crystallinity exotherm. According to Blatz, nylon-6 has a melting point (Tm) of 222°C and glass transition temperature (Tg) of 399C. This Tg value of nylon-6 is reasonable from the relationship Tg/Tm~0.6. The glass transition temperature of a nylon shifts to a lower temperature as the water content is increased. The T9 of nylon-66 decreases from.80°C for an almost dry sample to 15°C for a sample saturated with water (Starkweather, 1973). 2 .10 POLYMER BLENDS Polymer blends may be defined as intimate mixtures of two kinds of polymers, with no covalent bonds between them. Historically, the oldest and simplest method involves mechanical blending, where a plastic and a noncrosslinked elastomer are blended either on open rolls or through extruders (Matsuo, 1968). Materials prepared in this manner usually contain several percent of elastomer dispersed in a plastic matrix, as shown schematically in Figure 5: ////O /i// /o /o / °/' “ /o /O//{/ O 27 //////° 0/ Cc / o 7//%0/%//./7/ Figure 5: Schematic illustration of rubber droplets dispersed in a continuous plastic phase. In simple mechanical blends the plastic component usually predominates, with the dispersed elastomer having dimensions of the order of several micrometers. The shear action of mechanical blending also generates free radicals through polymer degradation reactions. The free radicals thus induced by mechanochemical action subsequently react to form a small number of true chemical grafts between the two components. The quantity and importance of such grafted material obviously depend on the exact mode of blending (Casale and Porter, 1971). Significant improvements in impact resistance and toughness are usually noted for such blends over the plain parent plastic, even in cases where no particular amount of grafting is noted. Polyblends are characterized by their phase behavior: miscible and immiscible. The miscible and immiscible are characterized by a glass transition temperature, exhibit homogeneity under magnification in an electron or phase contrast microscope and have physical properties intermediate between those of blend components. 2.10.1 Miscible and Immiscible Blends A blend with a glass transition temperature as well as a single amorphous phase will be classified as miscible. Films of miscible blends tend to be transparent, show smooth variation of properties with composition, and have only one phase. A miscible polymer blend will exhibit a single glass transition between the Tg's of the components with the sharpness of the transition similar to that of the components. However, blends of components having similar glass transition temperatures will provide ambiguous cases and other techniques must be employed. The advantages of use of miscible blends are to overcome specific problems such as processability, heat distortion, hardness, tensile strength, creep and so on. The physical properties of these ployblends are generally a compromise that, on balance, may be superior to the properties of the individual constituent polymers. Immisicibility in polymer blends is rarely well concealed, revealing itself as opacity or not opacity, delamination, double glass transition, discontinuous variation of properties with composition, having substantial morphology effects or combination of these properties because of the presence of two or more phase (Olabisi, et al. 1979, Gaicin, 1993). Blends of immiscible polymers have high interfacial tension and poor adhesion between two phases. This interfacial tension q .3) contributes to higher viscosities, difficulty in imparting desired degree of dispersion to random mixtures and to their subsequent lack of stability to phase separation during use. However, sometimes immiscibility is desirable to achieve a synergistic combination of the two polymers to form a polymer alloy. The miscibility or immiscibility of two polymers is dictated by the thermodynamics of the mixture. The free energy of mixing AGmix is given by AGm=AH . —TAS (26) mu mu This quantity, consisting of enthalpic (AG) and entropic (AS) parts, is a function of composition and temperature (T). For miscibility, AGmix must be negative. Because of the small number of moles of each polymer in the blend, the entropy of mixing is very small and so for most of the polymer blends , the free energy of mixing is positive. Specific interactions, like hydrogen bonding, dipole-dipole interactions or intramolecular repulsion effects can also lead to some degree of miscibility. This may explain the partial miscibility among halogenated polymers and those containing oxygen (Paul, 1978). Generally, blending technology rests on the premise of property additivity, although the additivity principle is not strictly valid for most polyblends. Although additivity is not always simple arithmetically for a quasi-binary miscible polyblend, extensive experimental data suggest that the following arithmetic semiempirical rule is obeyed by the glass transition temperature (T9) and the other physical properties: P=Plcm+onz+Ioloz (27) 32 Where P is the property of interest,from New Part Scientific Inc. was used to measure relative humidity during each run with a sensitivity error of 2 to 4%. 3. Temperature Since the permeability process is temperature dependent, the temperature was precisely controlled to avoid error within 1°C. SORPTION 1. Sensitivity of electro-balance The sensitivity of the electro-balance can be estimated at 10 micro grams, since it is placed in a special chamber and protected from potential 38 39 vibrations. External vibration transmitted to the electrobalance can cause unwanted errors. 2. Gas flow regulator The flow regulators used must be accurate and precise to generate an identical flow rate during the test and between replicate runs. In addition, the nitrogen gas used to generate proper vapor concentration has to be checked to maintain a constant pressure throughout the experiment. RESULTS AND DISCUSSION 1. SORPTION ISOTHERM 1.1 Equilibrium.Sorption Isotherm Water sorption isotherms were determined to characterize the sorption capacity of the blend. The sorption also is needed to relate the change in oxygen solubility to the presence of water. Water sorption isotherms were determined at 23°C. Sorption equilibrium values of water in the amorphous nylon/nylon-6 (20:80) are presented in Table 1. Table 1: The relationship between relative humidity and weight fraction Relative Humidity Weight Fraction 3 0.0029 6 0.0043 13 0.0123 48 0.0364 55 0.0428 58 0.0449 67 0.0526 75 0.0603 85 0.0793 4O 4] Figure 6 shows the plot of the experimental sorption values and Langmuir—Flory-Huggins values. The Langmuir-Flory-Huggins values were obtained by using a computer program prepared by Dr. R.J. Hernandez. A Flory—Huggins/Langmuir model was chosen for data description because this isotherm can be easily correlated with the adsorption (Langmuir) and absorption (Flory-Huggins) contribution. Figure 7 shows the plot of the sum of squares versus x, which was used in the calculation to determine the constants, x, B, and K of following equation: Ka V=FHa, +-—-'—— (28) l ( 1X.) 1+Ba, where a1 is the water activity. Starting with the value of 1 calculated by the first program, the values of K and B were calculated by a linear regression analysis of the equation (30) converted from the Langmuir equation (29). c C' ——=—15 mm p l+bp where: c is the equilibrium concentration of the penetrant in the polymer. p is the concentration of penetrant surrounding the solid. 1 1 B l ——f==——+~—-*-—- (30) W, K K a, where: WlL is expressed as following equation: WleW —WF” (31) exp where wexp is the experimental data and WFH is the Flory-Huggins value. 0.08 0% * g “- 004 : 4 E g e ) ( 0.02 : ‘ 4 . CHI = 1.746252, K = 5952668502, 8 = 72.78992 r ngmJir-Flay-mggins value L 9 e Expedment Vdue O l g 1 4 l . - i - 0 0.2 0.4 0.6 0.8 1.0 Water Activity Figure 6: Experiment sorption values and Langmuir-Flory-Huggins best fit 0.008 ~ ( 01136» 1 8 .5 0.004» 5 . 0.002: 0 - ‘ . . 1.740 1.745 1.750 1.755 CHI Figure 7: Sum of squares versus x at 25°C 1.760 For a series of x values, 44 the sum of squares of the difference between the experimental and calculated value were calculated. The values of x, B, and K were then associated with the minimum value of the sum of squares. The sum of squares was plotted as a function of x to find the best estimates of the parameters. The x values of the minimum of the convex curve should be the best estimation of the parameters. Table 2: Langmuir and Flory-Huggins weight fraction contribution Water Experimental F-H Langmuir Total Activity Values Values Values 0.03 0.00295 .941359E-03 .609202E-04 2.502280E—03 0.06 0.00428 .917263E-03 .654253E-04 4.582689E-03 0.13 0.0099 .669675E-03 .396251E-04 0.0094093 0.48 0.0364 .613822E-02 .950325E—04 3.693325E-02 0.55 0.0427 .258816E-02 .978581E-04 4.338602E-02 0.58 0.0445 .547782E-02 7.98865E—04 4.627669E-02 0.67 0.0526 .465947E-02 8.013558E-04 5.5460838-02 0.75 0.0603 6.36753E-02 8.030770E-04 6.437061E-02 0.85 0.0793 7.592858E-02 8.047801E-04 7.673336E-02 45 Table 3: K, B, and x parameter for water sorption in Nylon-6, Amorphous Nylon and Amorphous nylon/nylon-6 at 23°C K B x Nylon-6 0.1518 64.26 1.913 Amorphous Nylon 0.5370 58.48 1.712 Nylon Blend 0.0595 72.79 1.746 Table 2 shows the contribution of Langmuir and Flory-Huggins factors over the activity range at 25°C, using the parameter in Figure 2. As shown in Figure 1, the solid curve is best fit curve from Langmuir-Flory—Huggins model to the experimental values at 25°C. The Langmuir-Flory-Huggins model presented by Hernandez et al. (1991) describes accurately the sorption of water by nylon-6 as well as amorphous polyamide, over a broad range of water activity. The initial Langmuir contribution suggests the presence of a limited number of sorption sites which are immediately available to water molecules and following board extent may be indicative of clustering or multi-layer formation at the higher water activity (Kawasaki et al., 1962). Table 3 illustrates the K, B, and x parameters of Nylon-6, Amorphous Nylon and Nylon blend. 46 1.2 Equilibrium Sorption Isotherm in closed containers with salt solution The glass transition temperature was measured by using differential scanning calorimeter. The samples were equilibrated in closed containers with salt solution. To correlate DSC samples at a given humidity with their moisture content, the moisture content of the films was determined by two methods, Cahn Instrument and closed containers. Both results were comparable. The sorption isotherm values of water weight fraction determined in closed containers and the Cahn Electro-Balance are presented in Table 4. Figure 8 shows a sorption isotherm plot of water activity versus weight fraction via the two methods. The first is the Cahn instrument and the second is the closed containers with salt solution. The results from the second method were compared with the results from the Cahn Instrument, which correctly confirmed the accuracy of the closed containers with salt solution experiments. 47 0.08 0.07 0% Weight Faction O 2 A Closed containers' values I! l I Cahnlnstrument‘s values j sorption isotherm under various humidity model controlled by salt solution and measured by Cahn Instrument ,1 0.03 A , i 0.02 ‘ I ‘ l I 0.01 I ‘8 0 if I. r ‘ i . i 1 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 _ . Water Activity 1 i 1 Figure 8: Plot of weight fraction versus water activity distribution of 48 Table 4: Relative Humidity, weight of samples after drying, weight of samples after conditioning, and weight fraction RH(%) Weight after dry Weight after Weight Fraction (gm) condition (gm) 0.0538 0.0542 0.0074349 18.2 0.1022 0.1031 0.0088063 0.0919 0.0928 0.0097933 0.1471 0.1495 0.0163154 28 0.1572 0.1603 0.0197201 0.1165 0.1182 0.0145923 0.1468 0.1450 0.0298295 42 0.1110 0.1138 0.0252252 0.1245 0.1279 0.0273092 0.1681 0.1734 0.0315289 55 0.1776 0.1835 0.0332207 0.1391 0.1433 0.0301941 0.0728 0.0776 0.0659341 85 0.1326 0.1411 0.0641026 0.0838 0.0894 0.0668258 49 2. OXYGEN PERMEABILITY Oxygen permeability experiments were carried out at 23°C and within a range of 0 to 0.97 water activity. The plot of permeability from experiments showed that the system seemed to reach two different steady states (Figure 9). This behavior can be explained as a double diffusion mechanism. Accordingly, two simultaneous and independent diffusion processes, one fast and one slow, are proposed to be present during the whole experiment(Gavara and Hernandez, 92). In Figure 10, total oxygen permeability and permeability associated with the slow mechanism as well as the fast mechanism have been plotted as a function of water activity. The values of flow rate from each run were obtained as a function of time and permeability was calculated from the flow rate at the steady state by rewritten of the solution of Fick's law: 1(M) .A AU F‘ 4 1 w 2 _____'.=._':(D= — X2 ex —nX (32) _1_[AM) Foo (VI-I) rugs p( ) A At ,0 or using only the first term as: 4 l (I): — Xzex —X (33) ()6) p‘ ) where F (oxygen flow rate) represents AM/(AtA), A is the film surface, x =12/4Dt and "¢" is the ratio between the flow rate at time t and flow rate at the steady state. For permeability experiments, F values were obtained as a function of time from t = 0 to steady state. A Newton- Raphson method was used to evaluate x from equation (32) or (33) as a 50 O 100 200 300 400 500 fimdmm) Nylon Bend Room temperature Figure 9: The typical plotted graph between 1/x vs. time of Nylon Blend which it illustrated two mechanism of permeability. 51 function of time. The diffusion coefficient D is determined from the slope of the straight line of the plot 1/X versus t for values within the range 0.05<¢<0.97. _12__ _ (slope)!2 _ (34) 4X1 4 Otherwise, the permeability , P can be evaluated directly from permeability experiments: Fl P=— (35) AP Assuming that Henry's law applies in the case of oxygen in Nylon, the solubility coefficient, S, can be calculated from (36). P=DS (36) Because of two mechanisms of this experiment, the flow rate fraction is given by the equation (37). F F 4 l ‘5 l (D: "’ +——fi-=(——) X2 ex -n2X +Xzex —n2X (37) F Fl Jfi jug; p( f) s p( 5) 5,60 where "f" and "3" stands for fast and slow mechanism. For each value of ,Q D obtained for each mechanism given by equation (38). l2 I2 and D3 = Xft 4Xst (38) a value of P and S can be calculated P=—; P=Pf+P=—+—’—- (39) AP ‘ AP Pf =Dfo;Ps=DSSS (40) Experimental values of flow rate were obtained as a function of time and permeability was calculated from the flow rate at the steady state (Fm) by equation (35). Then the unknown variables in equation (37) XS, Xf, FS and Ff were obtained at time t as well as at the steady state. For runs that showed the dual mechanism the procedure for the determination of D and P values was as follows: For a range of values of Fco a series of plots 1/X vs. t was obtained. The highest correlation coefficient (R2>0.999) determined the best value of Fm. This value of Fm was assigned as the flow rate at the steady state for the fast mechanism, Ff w, Flow associated with the slow diffusion process, FS m, was obtained using equation (41). Fm=I'-"m-l-F:W (41) and Df from the slope of the plot using equation (38). DS (or XS) was calculated by substituting in equation (37) values of DS and minimizing the error between actual and calculated. Table 5 shows the slow and fast mechanism values of permeability, diffusion and solubility coefficient of oxygen in amorphous nylon/nylon-6 (20/80) at 23°C. Table 5: Permeability (P), Solubility (S), and Diffusion Coefficient values of oxygen transport in polymer at 23°C RH (1:) P 3 13x1010 cc(STP) .cm/m2.day.atm cc 02(STP) /cc polymer cmZ/second Slow Fast Slow Fast Slow Fast 0 .087987 .080224 0.228145 .537161 4.7 0.43 1.4 .085658 .077377 0.070815 .49261 14 0.60 3 .07893 .071684 0.06523 .976084 14 0.85 6 .075048 .062109 0.057907 .845705 15 0.85 10 .091869 .034418 0.04623 .265575 23 1.5 23 .065473 .015268 0.044576 .025245 19 7.0 37 .091869 .006987 0.053165 .047571 20 1.7 50 .087728 .01061 0.046153 .072237 2.2 1.7 74 .10491 .006987 0.023213 .020218 2.5 4.0 97 .112831 .001035 0.100455 .039936 1.3 0.3 020 - . l l . Cl Slow mechanism permeability 0 Fast mechanism permeability v Total permeability of slow and fast mechanism E 0.15 ’ '5 4 a s 1:. CU \ a) v E 5 0.10 ~ ( o A a 1 ‘L l- g i 8 i i 005: 0 A L A - 4 L 0 02 04 06 08 10 Water Activity Figure 10: Total oxygen permeability, blend at 2 3°C Fast and Slow mechanism of Nylon 55 Figure 10 shows the effect of relative humidity on the permeability coefficient. The diffusion and solubility coefficient values of oxygen in the polymer were obtained from this experiment by equation (34) and (36), respectively (Hernandez et al., 1986). The diffusion coefficient was calculated from a least-squares linear analysis of values from the unsteady state region for each permeability run. Solubility values were calculated from equation (12). The solubility of oxygen (S) is expressed in cc 02(STP)/cc polymer-water system. As shown in Figure 10, oxygen permeability decreased in the water activity range of 0 to 0.3 and then increased slightly as the water activity increased. For comparison reasons, Figure 11 shows the total oxygen permeability of Nylon-6, Amorphous nylon, and nylon blend (amorphous nylon/nylon-6:20/80). The oxygen permeability of the nylon blend is between nylon-6 and amorphous nylon beyond water activity 0.2. It shows that adding 20% amorphous nylon into nylon-6, it does significantly improve the oxygen permeability property of nylon-6 at the high range of water activity. Figure 12 and 13 present the effect of water activity on the diffusion and the solubility coefficients of oxygen in the blend, as a function of water activity respectively. 100 80 20’ 56 1.0 '9 <1 NWawBbmd <| 02 04 05 Water Activity 08 10 Figure 11: The permeability of Nylon-6, Amorphous Nylon, and Amorphous nylon/Nylon—6 (20:80) 2.5x10'9 2.0x109» (cmzlsec) Diffusion Coeffidem 57 1.5x10'9» 9’ El Slowmechan’sm 1.0x10’ 0 Fast media'ism 0.5x10'9 . Cl C] o i - - . E] 0 02 04 06 08 10 WaterActivity Figure 12: Fast and slow diffusion coefficient values of the nylon blend 58 20 Solubility (cm 02W polymer) 3 Figure 13: Total, fast, and slow mechanism solubility coefficient values of the blend at 23°C 2.5x10’9 2.0::10i9 » Diffusion Coefficient anzlseoond 0.5x109 59 1.5x109 o o o o v v e Diffus’on coefficient of Armpluis nylon v Diflusion coefficient of Nylon-6 o Dimsion coefficient of Amaphws nylorVnylon-G (20.80) 0.2 0.4 0.6 0.8 Water Adivity Figure 14: The fast mechanism of diffusion coefficient of Nylon-6, Amorphous Nylon, and the blend 10 60 20 a 15 1.0» ‘ Solubility oc O2 (STP)/oc polymer 7 v Solibilityof 0.5” D SollbilityofAmaplnlsNylon o SollbilityofAmorphwsNylonlNylon-GQQBO) v . ' o D e =\ - - 7_2 - , o - ' 1" - ‘1' . = 0 02 04 06 08 10 Figure 15: Total solubility of Nylon-6, Amorphous Nylon, and the blend 61 A statistical analysis using Student's t-test showed that the variable of diffusion coefficient as a function of water activity for both mechanism in Figure 12 are not significant with 95% confidence. Moreover, the diffusion coefficient is independent of the penetrant concentration. Thus, it can be concluded that D values for both mechanisms remain constant as water activity increases. Figure 14 presents fast mechanism of the diffusion coefficient of nylon—6, amorphous nylon, and the blend. The diffusion coefficient of the blend is higher than that of amorphous nylon for all of the water activity range but lower than nylon-6 in the water activity range below 0.3 and higher above 0.3. As shown in Figure 13, the oxygen solubility coefficient decreased in the range of low water activity (0-0.2), and tended to level off. Solubility values were calculated from the expression, S:5 (42) D Figure 15 illustrates the solubility of oxygen in nylon-6, amorphous nylon, and the blend. As indicated, solubility of oxygen in the blend at a water activity range below 0.2 is higher than nylon-6 and amorphous nylon. Beyond water activity at 0.2, the solubility values of the blend is between the nylon-6 and the amorphous nylon. 3. DIFFERENTIAL SCANNING CALORIMETRY (DSC) METHOD DSC method was used to determine the percent crystallinity of the blend and glass transition temperature under various water activity. Table 6 shows the glass transition temperature, melting temperature, enthalpy of the glass transition temperature and enthalpy of the melting temperature, and the last column shows the percent crystallinity of the blend. Crystallinity values of the samples were calculated as follows; . _ AH f % Crystallinity = (43) b Where AHb is the calculated heat of fusion of the blend that was calculated by (AHf* x 0.8) and AHf* is the heat fusion of 100% crystalline Nylon-6, equal to 195 J/g (Brandrup and Immergut, 1991). The average of the values of percent crystallinity was 32.1% 11.71%. As a comparison, Table 7 shows the crystallinity of Nylon-6 averages 42.8%. Table 6 shows the values of glass transition temperatures shifted to the lower temperature when samples were exposed to higher relative humidity. The glass transition temperatures of nylons shift to lower temperatures as water content is increased (Starkweather, 1973). 63 Table 6: The glass transition temperature, melting temperature, enthalpy of glass transition temperature and melting temperature, and % crystallinity of the blend RH (%) Tq (°C) Eq (J/g) Thfl°C) Em (J/g) %crystall 0 121.6 9.9 206.8 62.4 32.0 5 55.8 3.0 205.9 62.0 31.8 15 46.7 8.0 206.9 60.1 30.8 33 40.8 4.0 206.1 61.1 31.4 65 36.4 2.2 206.5 69.1 35.4 75 35.1 4.9 206.5 60.3 30.9 Table 7: The melting temperature, enthalpy, and % crystallinity of Nylon-6 Sample No. Thfi°C)1 E (J/g) %crystallinity 1 209.76 85.12 43.65 2 214.99 87.04 44.64 3 215.71 78.12 40.06 l Melting point of Nylon-6 is between 210 and 220°C (Hill, 87). CONCLUSIONS Sorption isotherm values of water in a Nylon blend were obtained over a wide range of water activities at 23°C. A Cahn electrobalance was used to determine the sorption isotherm in the Nylon blend. The moisture content in the samples was determined by the method using closed containers with salt solution. The results from this experiment were then used in the DSC testing. Computer programs were used to determine the values of three parameters (K, B, and x) of the Langmuir-Flory- Huggins equation to fit a weight fraction versus water activity curve from sorption isotherm experiments. As expected, the moisture isotherm of the blend lay in between the sorption isotherm of Nylon-6 and Nylon 6I/6T. The oxygen permeability behavior was determined as a function of water humidity at 23°C. The diffusion of oxygen was analyzed according to the bi-model diffusion model proposed by Gavara & Hernandez. Permeability, diffusion, and solubility values were determined for both mechanisms. The oxygen permeability coefficient of the blend decreased in the range of water activity from 0 to 0.3, and then increased as a function of water activity increased. From the oxygen permeability experiments, the diffusion and solubility coefficient were determined in order to describe accurately the mass transfer behavior of penetrant/barrier systems involving humidities. The solubility of oxygen in the blend tends to reach a plateau as the water activity increases above 0.2. 64 65 The decrease of oxygen solubility in polyamide may be interpreted by a decrease the number of active sites available to the oxygen molecules within the polymeric matrix. Although there is no evidence of changing crystallinity with an increase of water activity, the morphology of the polymer blend after water is sorbed might change and create more active sites during the blend sorbing. However, when oxygen permeability of a Nylon blend was compared with oxygen permeability of Nylon-6 and Amorphous Nylon, the oxygen permeability of Nylon blend is between Nylon-6 and Amorphous Nylon. It shows that adding 20% Amorphous Nylon into Nylon-6 can significantly improve the oxygen permeability property of Nylon-6. Differential Scanning Calorimetry (DSC) method was used to determine the crystallinity of the Nylon blend and to find a trend of the glass transition temperature of Nylon blend when it is exposed to various relative humidities. The results indicate that the percent crystallinity of the Nylon blend, 32.1% is less than that of Nylon-6, 42.8%. There is no statistically significant difference in crystallinity associated with an increase of water activity. The glass transition temperature of the Nylon blend shifts to lower temperatures as the water content is increased. For future work, a study to find an optimum value of percent of blending of Nylon-6/(6I/6T) addition which would encourage a constant oxygen permeability of Nylon would be seen most logical. :o 6.4 . a a r, a... n... a .u A . ..,<¢ » ,L A v I94 a .x. u ,- :v «:4 .4. :e 2)... . s , C of. .. .4 . l a L a... . u a e .d. Ex. .( a A l. .1)- I 4 e.( O o v as v . .4 n5 . v .2... a: rl v «(d .‘u ., l. s, H. l...- .\V gig .14 . 4 rr4 «(4» . e mi .44. . .y as. v .4. e p. U .L. .1). 2.. A d .4 In”; A :v a 04. .. no . L 1.“. A J a. v .4 e 1,4. '54 4V4 . v .44 Pk. n C r C '.~e » . era pkg P d N l -\ v A 4 :9 p\u A .v av; .5 v s .9 pr J.- J w .ml 4 . e p B..- pfiv . .e ;ru Pl - ./~ :r... .,4 .1y rue . s 154 unq- 100 REM box kamazu method for flory huggins model 105 REM program written by Dr. R.J. Hernandez, 1988 110 CLS : DIM A1(20), V1(20), ETA(20), X(20) 120 INPUT "HOW MANY POINTS?", N 130 INPUT "HOW MANY ITERATIONS?", ITE 140 INPUT "ENTER THE FIRST ESTIMATION OF CHI", B 150 PRINT "ENTER FIRST Al'S AND THEN Vl'S" 160 Al(l) = .03: A1(2) = .06: A1(3) = .13: A1(4) = .48: A1(5) = .55: A1(6) = .58 170 Al(7) = .67: A1(8) = .75: A1(9) = .85 190 V1(1) = .00295: V1(2) = .00428: V1(3) = .00993: V1(4) = .03641: 195 V1(5) = .04275: V1(6) = .04449: V1(7) = .05264: V1(8) = .06037: 200 V1(9) = .07928 210 PRINT u H", n 50", n 51", n CHI" 220 RL = 0! 225 RL = RL + 1 230 XTX = 0!: XTY = 0!: SO = 0!: 51 = 0! 240 REM EQUATION FOR THE MODEL 250 FOR K = 1 TO N 255 V2 = l - V1(K) 260 ETA(K) = V1(K) * EXP(V2 + B * V2 * V2) 270 NEXT K 280 REM EQUATION FOR THE SENSITIVITY COEFF 290 FOR K = 1 TO N 300 X(K) = V1(K) * V2 * V2 * EXP(V2 + B * V2 * V2) 310 NEXT K 315 REM CALCULATE 20, XTX, XTY 320 FOR K = 1 TO N 330 $0 = SO + (Al(K) - ETA(K)) * (Al(K) - ETA(K)) 340 XTX = XTX + X(K) * X(K) 350 XTY = XTY + X(K) * (Al(K) - ETA(K)) 360 NEXT K 370 DELTAB = XTY / XTX 380 REM CALCULATE G 390 G = DELTAB * DELTAB * XTX 400 IF (G < 0!) OR (G = O!) GOTO 670 410 H = 1! 420 B = B + DELTAB * H 430 REM CALCULATE ETA'S WITH 8'5 440 FOR K = 1 TO N 450 ETA(K) = V1(K) * EXP(V2 + B * V2 * V2) 460 NEXT K 560 REM CALCULATE 51 570 FOR K = 1 TO N 580 51 = 51 + (Al(K) - ETA(K)) * (Al(K) - ETA(K)) 590 NEXT K 600 JJ = SO - (2 - (l / 1.1)) * G 610 IF (51 < JJ) OR (51 = JJ) GOTO 640 615 B = B - H * DELTAB 620 H = G / (Sl - SO + 2! * G) 630 B = B + H * DELTAB 640 PRINT H, SO, 51, B 66 PUEPEBHDIXIIX Computer Program for Flory-Huggins Model 650 IF 660 IF (RL < (RL = 670 PRINT "G 680 END ITE + l) ITE) GOTO :11, G GOTO 225 680 67 .5 p,/. 3.. 2.. :x. 2.. 2.. En . s L. 11 is we 0.. A). s 4 .l—c . 1 . l. .li. .1. .l.. q a . o . . a L . a . o w a w L a o . a . . u b UV” ”V“ H: :. an :1 7L ”v. a. . use ”In Vi. KN“ Irv H . PKv A w pk. .llv Ev Aim. A Iv ; 4 R V K. J A. .V only ..lv ‘1 a .. n L .4... lb. 4.1 1o 1 c (C a... 0 v .3 .. J . . . . A L a... . g . e u a «I o a o 4 Q ~ ¢ -. u . a . c g . A/G A.‘ Alla A/h A In ‘be ‘I‘ n\~ ~l\~ Almv rlo a . are pl/h 9.15 !\L ~\U .)J r... a .4 _~. ‘1». A ,L a. (.0 «(4 aka add .13 u; .u. A): «(U 6}»... wk U a c 110 Ufa RN. (1» .4 A 1v n v Add C. .~ . / e .44 I - . A.“ PC a: 0.. .0 A v a: a .~,u «<4 I? 1.1 .(v .14.. .JJ .... a C P. a (V .4 o .4). A1v 100 102 104 105 106 108 110 112 118 121 122 126 127 135 140 145 150 155 160 170 180 190 200 210 215 220 224 230 240 243 250 255 260 270 280 290 295 300 302 303 310 315 320 325 330 340 345 350 370 68 IUEPEFHDIXIIB Computer Program for Langmuir-Flory-Huggins Model REM THIS PROGRAM CALCULATES K AND B FOR LANGMUIR REM COMPONENT FRACTION GIVEN CHI THAT HAS BEING OBTAINED REM USING FLORY.BAS IT TAKES THE DIFFERENCE BETWEEN REM EXPERIMENT SORPTION VALUES REM AND DO A LEAST SQUARE ANALYSIS TO GET K AND B REM IT ALSO GIVES THE CORRELATION COEFFICIENT FOR REM THE LINEAR CORRELATION AS WELL AS THE SUM OF SQUARE REM FOR THE EXPERIMENTAL AND LANGMUIR-FLORY-HUGGINS MODEL DIM A(30), W(30), M(30), L(30), LG(30), MFH(30) A(l) = 0!: A(2) = .03: A(3) = .06: A(4) = .13: A(5) = .48: A(6) = .55 A(7) = .58: A(8) = .67: A(9) = .75: A(lO) = .85 M(l) = 0!: M(2) = .00295: M(3) = .00428: M(4) = .0099: M(5) = .0364 M(6) = .0427: M(7) = .0445: M(B) = .0526: M(9) = .0603: M(lO) = .0793 INPUT "ENTER VALUE OF CHI ", CHI PRINT "CHI VALUE USED=", CHI PRINT "ACTIVITY"; "EXPERIMENT "; " F - H "; " LANG. "; " MFH "; FOR I = 2 TO 10 REM FIRST GUESS FOR VOLUME FRACTION: X=A(I)/10 FOR II = 1 TO 4 Z = 1 - X Y Z + CHI * Z * Z F X * EXP(Y) - A(I) FP = EXP(Y) * (l - X * (2 * CHI * Z + 1)) X = X - F / FP W(I) = X NEXT II REM CALCULATE EXPERIMENT F-H TO GIVE LANG. COMP. SA = O: SSA = 0: SL = 0: SSL = 0 NEXT I FOR I = 2 TO 10 REM LINER REG. TO CALCULATE K&B IN LAPY L(I) = M(I) - W(I) SL = SL + (1 / L(I)) SA = SA + (1 / A(I)) SAL = SAL + (1 / A(I)) * (1 / L(I)) SSA = SSA + (l / A(I)) * (l / A(I)) SSL = SSL + (1 / L(I)) * (1 / L(I)) NEXT I PRINT "SL="; SL, "SA="; SA, PRINT "SAL="; SAL, "SSA="; SSA REM CALCULATE K K = (12 * SSA - SA * SA) / (12 * SAL - SA * SL) REM CALCULATE B/K BOK = ((5L * SSA) — (SA * SAL)) / ((12 * SSA) - SA * SA) B = BOK * K REM CALCULATE SUM OF SQUARE FOR EXPERIMENTAL AND CALCULATED, SST SST = 0 FOR I = 2 TO 10 LG(I) = K * A(I) / (l + B * A(I)) 380 400 430 440 450 455 460 465 468 470 475 480 490 69 SST = SST + ((M(I) - W(I) - LG(I))) A 2 MFH(I) = W(I) + LG(I) PRINT A(I); M(I); W(I); LG(I); MFH(I) NEXT I SY = 0: SAY = 0 FOR I = 2 TO 10 SY = SY + (1 / L(I) - BOK - (1 / K) * (1 / A(I))) A 2 SAY = SAY + (1 / L(I) - SL / 12) A 2 NEXT I REM CALCULATE CORRLATION COEFFICIENT SR = 1 - SY / SAY PRINT "SUM OF SQUARE ="; SST, "K="; K, "B="; B, "SR="; SR END P}. I! 70 APPENDIX C The Calculation Method of Weight Fraction Water sorption isotherm of Nylon blend were determined by Cahn Instrument. The weight of material was measured and recorded as a function of time by Cahn Instrument. The weight fraction of each relative humidity at steady state was calculated by following equation. Height Fraction Calculation W). =-—————- (C) Wp+Wh Wf where Wf is weight fraction, Wh is weight of water gained, and Wp is weight of polymer dried. Table 8 shows the weight fraction values were calculated by using equation (c) at each relative humidity at steady state. 71 Table 8: The calculation of weight fraction at steady state of various humidities RH (i) Weight at Water gained Weight Fraction steady state(gm) (gm) 0 81.997 0 0 3 82.24 0.243 0.002952 6 82.35 0.353 0.004284 13 82.82 0.823 0.009935 48 85.096 3.099 0.036415 55 85.66 3.663 0.042754 58 85.815 3.818 0.044488 67 86.553 4.556 0.052636 75 87.523 5.526 0.060366 85 89.321 7.324 0.079276 72 APPENDIX D The Experimental and Known values in each plot in the results and dicussions part Table 9: The total permeability values of Nylon blend, Nylon—6, Amorphous Nylon Water Nylon Blend Nylon-6 Amorphous Nylon Activity 0.00 66.22441 48.41604 57.5 0.014 65.36811 44.80000 47.0 0.03 59.29685 41.31921 40.0 0.06 53.99882 40.50000 37.0 0.10 49.71929 39.42669 34.5 0.23 31.78780 33.90706 29.9 0.37 33.00000 34.38017 27.6 0.50 38.71575 45.00000 26.4 0.74 44.05394 71.59907 24.7 0.97 44.82913 85.93172 24.2 and Table 10: Fast diffusion coefficient values of Nylon blend, Nylon-6 and Amorphous Nylon Water Nylon Blend Nylon-6 Amorphous Nylon Activity 0.00 4.70E-10 1.58E-09 6.00E-10 0.014 1.40E-09 1.62E-09 6.30E-10 0.03 1.40E-09 1.75E-09 6.50E—10 0.06 1.50E-09 2.00E-09 7.30E—10 0.10 2.30E—09 2.30E-09 7.50E—10 0.23 1.90E—09 1.90E-09 8.00E-10 0.37 2.00E-09 1.80E-09 8.50E-10 0.50 2.20E-09 1.30E-09 9.00E-10 0.74 2.50E-09 5.00E-10 1.00E-09 0.97 1.30E-09 3.00E-10 1.20E-09 Int-3 ‘9- 1\:a_ Table 11: Total solubility coefficient values of Nylon blend, Nylon-6, and Amorphous Nylon 73 Water Nylon blend .Amorphous Nylon Nylon-6 Activity 0.000 1.765306 0.30 0.500 0.014 1.563425 0.28 0.470 0.030 1.041314 0.18 0.300 0.060 0.903612 0.16 0.250 0.100 0.311805 0.14 0.200 0.230 0.069821 0.11 0.050 0.370 0.100736 0.90 0.050 0.500 0.118390 0.80 0.025 0.740 0.043431 0.70 0.025 0.970 0.140391 0.70 0.025 Table 12: x and sum of square value 1 Sum of square 1.7426 0.00176650 1.74273 0.00140102 1.74293 0.00117766 1.74309 0.00101523 1.74326 0.00093401 1.74339 0.000873096 1.74359 0.000791878 1.74383 0.00071066 1.74403 0.000629442 1.74419 0.000568528 1.74429 0.000527919 1.74459 0.000467005 1.74479 0.000406092 1.74499 0.000365482 1.74512 0.000284264 1.74522 0.000243655 1.74546 0.00022335 1.74569 0.000162437 1.74582 0.000142132 1.74609 0.000142132 1.74625 0.00014132 1.74636 0.000182741 1.74662 0.00022335 1.74689 0.000284264 1.74799 0.000670051 1.75062 0.00209137 1.75128 0.00255838 1.75567 0.00625381 Ta} 74 1XPPENEH3(IE Data of Sorption Isotherm tested by Cahn Instrument Table 13: Sorption isotherm values from o to 3% RH. Time (min.) Weight (gms) 30 81.9972 60 82.1081 90 82.1872 120 82.2211 150 82.2347 180 82.2368 210 82.2388 240 82.2398 270 82.2435 300 82.2437 330 82.2440 360 82.2447 390 82.2449 420 82.2448 450 82.2450 480 82.2441 510 82.2439 540 82.2424 570 82.2435 600 82.2442 630 82.2445 660 82.2443 690 82.2437 720 82.2431 750 82.2429 780 82.2427 810 82.2430 840 82.2437 870 82.2441 900 82.2444 930 82.2424 960 82.2429 990 82.2422 Tal: Tale-‘I‘IIEII‘I‘I‘I‘I ” 11111111111111111111111allnan-all11u1222222‘ 75 Table 14: Sorption Isotherm values from 3 to 62 Time Wieght (g) Time Wieght (3) Time Wieght (3) Time Wie ht ) 690 82.2437 2190 82.3470 3690 82.3445 5370 82.341 1 720 82.2431 2220 82.3471 3720 82.3458 5400 82.3428 750 82.2429 2250 82.3469 3750 82.3459 5430 82.3435 780 82.2427 2280 82.3467 3780 82.3467 5460 82.3449 810 82.2430 2310 82.3466 3810 82.3489 5490 82.3458 840 82.2437 2340 82.3469 3840 82.3494 5520 82.3467 870 82.2441 2370 82.3468 3870 82.351 1 5550 82.3468 900 82.2444 2400 82.3475 3900 82.3522 5580 82.3475 930 82.2424 2430 82.3500 3930 82.3524 5610 82.3477 960 82.2429 2460 82.3520 3960 82.3526 5640 82.3476 990 82.2422 2490 82.3499 3990 82.3528 5670 82.3467 1020 82.2420 2520 82.3475 4020 82.3527 5700 82.3468 1050 82.2415 2550 82.3488 4050 82.3521 5730 82.3434 1080 82.241 1 2580 82.3489 4080 82.3519 5760 82.3418 1110 82.2409 2610 82.3457 4110 82.3514 5790 82.3444 1140 82.2253 2640 82.3512 4140 82.3500 5820 82.3459 1 170 82.2355 2670 82.3488 4170 82.3487 5850 82.3487 1200 82.2255 2700 82.3463 4200 82.3479 5880 82.3508 1230 82.2529 2730 82.3478 4230 82.3473 5910 82.3522 1260 82.2730 2760 82.3476 4260 82.3465 5940 82.3521 1290 82.281 1 2790 82.3474 4290 82.3455 5970 82.3516 1320 82.2862 2820 82.3471 4320 82.3446 6000 82.3555 1350 82.2869 2850 82.3469 4350 82.3456 6030 82.3515 1380 82.2850 2880 82.3444 4380 82.3468 6060 82.3504 1410 82.2866 2910 82.3400 4410 82.3469 6090 82.3475 1440 82.2898 2940 82.3456 4440 82.3477 6120 82.3476 1470 82.2927 2970 82.3468 4470 82.3450 6150 82.3514 1500 82.2958 3000 82.3487 4500 82.3512 6180 82.3526 1530 82.2990 3030 82.3498 4530 82.3525 6210 82.3576 1560 82.3024 3060 82.3574 4560 82.3512 6240 82.3598 1590 82.3056 3090 82.3570 4590 82.3524 6270 82.3580 1620 82.3084 3120 82.3564 4620 82.3500 6300 82.3575 1650 82.31 12 3150 82.3562 4650 82.3468 6330 82.3576 1680 82.3145 3180 82.3551 4680 82.3479 6360 82.3588 1710 82.3168 3210 82.3522 4710 82.3502 6390 82.3589 1740 82.3191 3240 82.3501 4740 82.3515 6420 82.3597 1770 82.3225 3270 82.3491 4770 82.3518 6450 82.3595 1800 82.3255 3300 82.3479 4800 82.3542 6480 82.4038 1830 82.3284 3330 82.3476 4830 82.3539 6490 82.4799 1860 82.3309 3360 82.3466 4860 82.3541 6500 82.5363 1890 82.3339 3390 82.3463 4890 82.3527 6510 82.5766 1920 82.3366 3420 82.3461 4920 82.3514 6520 82.6076 1950 82.3396 3450 82.3465 4950 82.3500 6530 82.6323 1980 82.3415 3480 82.3460 4980 82.3487 6540 82.6517 2010 82.3455 3510 82.3459 5010 82.3475 6550 82.6680 2040 82.3465 3540 82.3502 5040 82.3471 6560 82.6794 2070 82.3467 3570 82.3502 5070 82.3462 6570 82.6912 2100 82.3468 3600 82.3488 5280 82.3432 6580 82.7017 2130 82.3469 3630 82.3447 5310 82.3420 6590 82.7117 2160 82.3470 3660 82.3412 5340 82.3400 6600 82.7204 fi Table 1 ITime (m 76 Table 15: Sorption Isotherm Values from 6 to 13% RH Time (min) Weight (9) Time (min) Weight (9) Time (min) Weight (9) Time (min) Weight (g) 6390 82.3589 6940 82.8596 7390 82.9782 7840 83.0058 6420 82.3597 6950 82.8641 7400 82.9801 7850 82.9773 6450 82.3595 6960 82.8684 7410 82.9831 7860 82.9823 6480 82.4038 6970 82.8722 7420 82.9851 7870 83.001 1 6490 82.4799 6980 82.8761 7430 82.9873 7880 83.0086 6500 82.5363 6990 82.8804 7440 82.989 7890 83.0096 6510 82.5766 7000 82.884 7450 82.9912 7900 83.0101 6520 82.6076 7010 82.8881 7460 82.9926 7910 83.0103 6530 82.6323 7020 82.8917 7470 82.9925 7920 83.01 6540 82.6517 7030 82.8934 7480 82.991 7930 83.0106 6550 82.668 7040 82.8953 7490 82.9891 7940 83.01 1 6560 82.6794 7050 82.8974 7500 82.9869 7950 83.01 15 6570 82.6912 7060 82.899 7510 82.9843 7960 83.01 15 6580 82.7017 7070 82.9015 7520 82.9813 7970 83.0124 6590 82.71 17 7080 82.904 7530 82.9781 7980 83.0127 6600 82.7204 7090 82.9067 7540 82.9921 7990 83.0134 6610 82.7288 7100 82.909 7550 83.008 8000 83.0148 6620 82.7351 71 10 82.912 7560 83.0091 8010 83.0171 6630 82.7391 7120 82.9147 7570 83.0058 8020 83.0184 6640 82.744 7130 82.9177 7580 83.0022 8030 83.0208 6650 82.7485 7140 82.9197 7590 82.9996 8040 83.024 6660 82.7514 7150 82.9223 7600 82.998 8050 83.0274 6670 82.757 7160 8.2.9248 7610 82.9972 8060 83.0306 6680 82.7613 7170 82.9273 7620 82.9963 8070 83 .0344 6690 82.767 7180 82.9305 7630 82.9961 8080 83.0379 6700 82.7739 7190 82.933 7640 82.9962 8090 83.0414 6710 82.7809 7200 82.9356 7650 82.9956 8100 83.0438 6720 82.7873 7210 82.9373 7660 82.9964 81 10 83.0463 6730 82.7941 7220 82.9408 7670 82.9971 8120 83.049 6740 82.8001 7230 82.9428 7680 82.9968 8130 83.0522 6750 82.8057 7240 82.9447 7690 82.9974 8140 83.0556 6760 82.7954 7250 82.94661 7700 82.9976 8150 83.0588 6770 82.7855 7260 82.9476 7710 82.9982 8160 83.0626 6780 82.7866 7270 82.9492 7720 82.9986 8170 83.067 6790 82.7915 7280 82.9508 7730 82.9996 8180 83.0696 6800 82.7973 7290 82.9526 7740 82.9997 8190 83.0728 6810 82.8034 7300 82.9538 7750 83.0002 8200 83.075 6820 82.8083 7310 82.956 7760 83.0009 8210 83.0782 6830 82.8134 7320 82.9598 7770 83.0021 8220 83.0798 6840 82.8186 7330 82.9626 7780 83.0018 8230 83.0623 6850 82.8235 7340 82.965 7790 83.0027 8240 83.0723 6860 82.8287 7350 82.9689 7800 83.0034 8250 83.0651 6870 82.8335 7360 82.971 7810 83.0035 8270 83.0495 6880 82.8386 7370 82.9733 7820 83.0042 8280 83.0448 6890 82.8427 7380 82.9757 7830 83.0049 8290 83.0409 77 Time (min) Weight (9) Time (min) Weight (9) Time (min) Weight (g) 8300 8310 8320 8330 8340 8350 8360 8370 8380 8390 8400 8410 8420 8430 8440 8450 8460 8470 8480 8490 8500 8510 8520 8530 8540 8550 8560 8570 8580 8590 8600 8610 8620 8630 8640 83.0385 83.0378 83.0376 83.0376 83.0378 83.0381 83.0377 83.0372 83.0372 83.0371 83.0374 83.0372 83.0373 83.0369 83.0376 83.0378 83.0379 83.0388 83.0388 83.0392 83.0395 83.0401 83.0404 83.0405 83.0408 83.0409 83.0422 83.0423 83.0426 83.0426 83.0427 83.0434 83.0435 83.0443 83.0442 8650 8660 8670 8680 8690 8700 8710 8720 8730 8740 8750 8770 8780 8790 8800 8810 8820 8830 8840 8850 8860 8870 8880 8890 8900 8910 8920 8930 8940 8950 8960 8970 8980 8990 9000 83.0439 83.0435 83.0427 83.0428 83.0424 83.0421 83.0418 83.0421 83.0417 83.0417 83.0412 83.0413 83.0412 83.0413 83.0415 83.0417 83.0415 83.0412 83.0414 83.0409 83.0412 83.0407 83.0399 83.0388 83.0386 83.0365 83.0349 83.0323 83.0304 83.0285 83.0254 83.0233 83.0209 82.9953 83.0006 9010 9020 9030 9040 9050 9060 9070 9080 9090 9100 9110 9120 9130 9140 9150 9160 9170 9180 9190 9200 9210 9220 9230 9240 9250 9260 9270 9280 9290 9300 9310 9320 9330 9340 9350 83.0136 83.0176 83.0182 83.0173 83.0166 83.0156 83.0157 83.0162 83.016 83.016 83.0164 83.0168 83.0173 83.0174 83.0176 83.0174 83.0172 83.0171 83.0166 83.0168 83.0166 83.0164 83.0169 83.0168 83.017 83.0179 83.0181 83.0184 83.0189 83.0192 83.0199 83.0201 83.0206 83.0213 83.0215 78 Table 16: Sorption Isotherm Values from 13 to 48 % RH Time (min) Weight (9) Time (min) Weight (9) Time (min) Weight (9) Time (min) Weight (g) I 9360 83.0222 9800 84.9096 10240 85.0267 10690 9370 83.0252 9810 84.9151 10250 85.0278 10700 9380 83.1539 9820 84.9213 10260 85.0293 10710 9390 83.3451 9830 84.9276 10270 85.0307 10720 9400 83.5655 9840 84.933 10280 85.0322 10730 9410 83.7882 9850 84.9381 10300 85.0349 10740 9420 83.9842 9860 84.9345 10310 85.0366 10750 9430 84.1458 9870 84.9458 10320 85.0378 10760 9440 84.2716 9880 84.9538 10330 85.0389 10770 9450 84.3675 9890 84.9592 10340 85.0394 10780 9460 84.4409 9900 84.9629 10350 85.042 10790 9470 84.4975 9910 84.966 10360 85 .0435 10800 9480 84.541 1 9920 84.9694 10370 85.0445 10810 9490 84.576 9930 84.9725 10380 85.0452 10820 9500 84.6058 9940 84.9755 10390 85.0448 10830 9510 84.6303 9950 84.9781 10400 85.0443 10840 9520 84.6515 9960 84.9806 10410 85.046 10850 9530 84.67 9970 84.9826 10420 85.0475 10860 9540 84.6863 9980 84.9856 10430 85.0483 10870 9550 84.7002 9990 84.9872 10440 85.0494 10880 9560 84.7128 10000 84.9888 10450 85.051 1 10890 9570 84.7248 10010 84.9906 10460 85.0522 10900 9580 84.7371 10020 84.9922 10470 85.0536 10910 9590 84.7485 10030 84.9945 10480 85.0549 10920 9600 84.7588 10040 84.9967 10490 85 .057 10930 9610 84.7692 10050 84.9983 10500 85.0585 10940 9620 84.7795 10060 85.0005 10510 85.0587 10950 9630 84.7767 10070 85 .0018 10520 85.06 10960 9640 84.7975 10080 85.0034 10530 85.0609 10970 9650 84.8097 10090 85.0051 10540 85.0625 10980 9660 84.8184 10100 85 .0056 10550 85.064 10990 9670 84.8252 101 10 85.0066 10560 85.0654 1 1000 9680 84.8331 10120 85.0077 10570 85.0666 1 1010 9690 84.8419 10130 85.0088 10580 85.0675 1 1020 9700 84.8492 10140 85.0106 10590 85.0688 11030 9710 84.8572 10150 85.0134 10600 85.069 11040 9720 84.8649 10160 85.0155 10610 85.0695 1 1050 9730 84.8722 10170 85.0166 10620 85.0698 1 1060 9740 84.8783 10180 85.0183 10630 85.0696 1 1070 9750 84.8837 10190 85.0204 10640 85.0706 1 1080 9760 84.8889 10200 85.0211 10650 85.0715 11090 9770 84.8953 10210 85.0226 10660 85.0725 11100 9780 84.9 10220 85.0245 10670 85.0733 1 1 1 10 9790 84.9052 10230 85 .0251 10680 85 .0745 1 1 120 11—4“ 79 Table 17: Sorption Isotherm Values from 48 to 55% RH Time (min) Weight (9) Time (min) Weight (9) Time (min) Weight (9) Time (min) Weight (9) 11130 85.0188 11590 85.4369 12040 85.483 12490 85.5563 11140 85.0588 11600 85.4385 12050 85.484 12500 85.5567 11150 85.1569 11610 85.4399 12060 85.4857 12510 85.5565 1 1 160 85.2142 1 1620 85.441 1 12070 85.4864 12520 85.5561 1 1 170 85.2482 1 1630 85.4419 12080 85.4883 12530 85.5563 1 1 180 85.2717 11640 85.4421 12090 85.4899 12540 85.5565 1 1 190 85.2895 1 1650 85.4434 12100 85.4906 12550 85.5562 1 1200 85.3056 1 1660 85.4452 12110 85.4919 12560 85.5567 11210 85.3187 11670 85.446 12120 85.4928 12570 85.5565 1 1220 85.3296 1 1680 85.4472 12130 85.4936 12580 1 1230 85.3392 1 1690 85.4485 12140 85.4951 12590 1 1240 85.3472 1 1700 85.4489 12150 85.4961 12600 1 1250 85.3542 1 1710 85.4498 12160 85.4975 12610 1 1260 85.3608 1 1720 85.4501 12170 85.4984 12620 1 1270 85.3661 1 1730 85.4506 12180 85.4995 12630 1 1280 85.3707 1 1740 85.4508 12190 85.5008 12640 1 1290 85.3753 1 1750 85.4513 12200 85.5012 12650 1 1300 85.3794 1 1760 85.4517 12210 85.5025 12660 1 1310 85.3834 1 1770 85.4523 12220 85.5036 12670 1 1320 85.3861 1 1780 85.4525 12230 85.5044 12680 1 1330 85.3877 1 1790 85.4527 12240 85.5057 12690 1 1340 85.3905 1 1800 85.4535 12250 85.5071 12700 1 1350 85.3932 1 1810 85.4543 12260 85.5083 12710 1 1360 85.3958 1 1820 85.4551 12270 85.5087 12720 1 1370 85.3982 1 1830 85.4562 12280 85.5094 12730 1 1380 85.4005 1 1840 85.4578 12290 85.5095 12740 1 1390 85.4026 1 1850 85.4584 12300 85.5101 12750 11400 85.4039 11860 85.4597 12310 85.5113 12760 11410 85.4057 11870 85.4613 12320 85.5134 12770 1 1420 85.4075 1 1880 85.4618 12330 85.5166 12780 1 1430 85.4091 1 1890 85.4627 12340 85.5208 12790 1 1440 85.4104 1 1900 85.463 12350 85.5251 12800 11450 85.4127 11910 85.4649 12360 85.5287 12810 1 1460 85.4146 1 1920 85.4663 12370 85.5321 12820 1 1470 85.4161 1 1930 85.468 12380 85.5352 12830 1 1480 85.418 1 1940 85.469 12390 85.538 12840 1 1490 85.4202 1 1950 85.4706 12400 85.5405 12850 11500 85.4219 11960 85.472 12410 85.5431 12860 1 1510 85.4242 1 1970 85.4732 12420 85.5454 12870 1 1520 85.4258 1 1980 85.4748 12430 85.5475 12880 1 1530 85.4276 1 1990 85.4761 12440 85.5491 12890 1 1540 85.4299 12000 85.4779 12450 85.551 12900 11550 85.4315 12010 85.4791 12460 85.5527 12910 1 1560 85.4326 12020 85.4805 12470 85.5539 12920 1 1570 85.4338 12030 85.4815 12480 85.555 12930 80 Time (min) Weight (9) Time (min) Weight (9) Time (min) Weight (9) Time (min) Weight (9) 12940 85.5741 13430 85.6069 13910 85.6459 14390 85.6595 12950 85.5751 13440 85.6083 13920 85.6468 14400 85.6595 12960 85.5766 13450 85.6097 13930 85.6476 14410 85.6595 12970 85.5773 13460 85.6108 13940 85.6477 14420 85.6595 12980 85.5783 13470 85.6123 13950 85.6486 14430 85.6595 12990 85.5793 13480 85.6136 13960 85.6494 14440 85.6595 13000 85.5805 13490 85.6146 13970 85.6503 14450 13010 85.5818 13500 85.6149 13980 85.6508 14460 13020 85.5837 13510 85.6156 13990 85.6514 14470 13030 85.5858 13520 85.616 14000 85.6527 14480 13040 85.5875 13530 85.6169 14010 85.6541 14490 13050 85.589 13540 85.6172 14020 85.6551 14500 13060 85.5899 13550 85.6185 14030 85.6555 14510 13070 85.5903 13560 85.6207 14040 85.6559 14520 13080 85.5916 13570 85.6228 14050 85.6563 14530 13090 85.592 13580 85.6244 14060 85.6566 14540 13100 85.5926 13590 85.6257 14070 85.6569 14550 131 10 85.5924 13600 85.6269 14080 85.6572 14560 13120 85.5921 13610 85.6277 14090 85.6575 14570 13130 85.5929 13620 85.628 14100 85.6578 14580 13140 85.5937 13630 85.6287 14110 85.6581 14590 13150 85.5944 13640 85.6296 14120 85.6583 14600 13160 85.5949 13650 85.6302 14130 85.6585 14610 13170 85.5951 13660 85.6307 14140 85.6587 14620 13180 85.596 13670 85.6316 14150 85.6589 14630 13190 85.5961 13680 85.6327 14160 85.6591 14640 13200 85.5963 13690 85.6331 14170 85.6593 14650 13210 85.5961 13700 85.6342 14180 85.6594 14660 13220 85.5965 13710 85.6347 14190 85.6594 14670 13230 85.5974 13720 85.6348 14200 85.6596 14680 13240 85.5974 13730 85.6362 14210 85.6594 14690 13250 85.5987 13740 85.6367 14220 85.6595 14700 13260 85.5991 13750 85.6382 14230 85.6596 14710 13270 85.5996 13760 85.6387 14240 85.6595 14720 13280 85.5999 13770 85.6386 14250 85.6594 14730 13290 85.6001 13780 85.6403 14260 85.6595 14740 13300 85.6003 13790 85.6405 14270 85.6595 14750 13310 85.6004 13800 85.6409 14280 85.6595 14760 13320 85.603 13810 85.6413 14290 85.6595 14770 13330 85.6034 13820 85.6416 14300 85.6595 14780 13340 85.6032 13830 85.641 14310 85.6595 14790 13350 85.6038 13840 85.6417 14320 85.6595 14800 13360 85.6035 13850 85.6424 14330 85.6595 14810 13370 85.6041 13860 85.6434 14340 85.6595 14820 13380 85.6041 13870 85.6435 14350 85.6595 14830 13390 85.6045 13880 85.6445 14360 85.6595 14840 13400 85.6047 13890 85.6453 14370 85.6595 14850 13410 85.6057 13900 85.6449 14380 85.6595 14860 81 Time (min) Weight (9) Time (min) Weight (9) Time (min) Weight (9) Time (min) WGith (9)11 14870 14880 14890 14900 14910 14920 14930 14940 14950 14960 14970 14980 14990 15000 15010 15020 15030 15040 15050 15060 15070 15080 15090 15100 15110 15120 15130 15140 15150 15160 15170 15180 15190 15200 15210 15220 15230 15240 15250 15260 15270 15280 15290 15300 15310 15320 15330 15340 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 15360 15370 15380 15390 15400 15410 15420 15430 15440 15450 15460 15470 15480 15490 15500 15510 15520 15530 15540 15550 15560 15570 15580 15590 15600 15610 15620 15630 15640 15650 15660 15670 15680 15690 15700 15710 15720 15730 15740 15750 15760 15770 15780 15790 15800 15810 15820 15830 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 15840 15850 15860 15870 15880 15890 15900 15910 15920 15930 15940 15950 15960 15970 15980 15990 16000 16010 16020 16030 16040 16050 16060 16070 16080 16090 16100 16110 16120 16130 16140 16150 16160 16170 16180 16190 16200 16210 16220 16230 16240 16250 16260 16270 16280 16290 16300 16310 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 85.6596 16320 16330 16340 16350 16360 16370 16380 16390 16400 16410 16420 16430 16440 16450 16460 16470 16480 16490 16500 16510 16520 16530 16540 16550 16560 16570 16580 16590 16600 16610 16620 16630 16640 16650 16660 16670 16680 16690 16700 16710 16720 16730 16740 16750 16760 16770 16780 16790 85.659 . 85.6596) 85.65961 85.659 .1 85.659 .1 85.659 .( 85.659 .5 85.659 .1 85.659 9! 85.659 .1 85.6596] 85.659 - 85.6596| 85.659 =~~ 85.659 - 85.659 .- 85.659 :1) 85.659 a; 85.659 .1 85.6596 85.659 °j 85.659 . 85.659 9? 85.659 .1 85.659 8' 85.659 .2 85.659 :4 85.659 .) 85.659 . 85.659 .3 85.659 4 85.659 ’) 85.659 -; 85.659 .; 85.659 .1 85.659 8 85.659 .1 85.659 a; 85.659 :1 85.659 .1 85.659 85.659 .1 85.659 . 85.6596 85.659 -} 85.6596) 85.659 85.659 .! 82 Time (min) Weight (9) Time (min) Weight (9) Time (min) Weight (9) Time (min) Weight (9) II 15350 85.6596 16580 85.6596 16830 85.6596 17110 16320 85.6596 16590 85.6596 16840 85.6596 17120 16330 85.6596 16600 85.6596 16850 85.6596 17130 16340 85.6596 16610 85.6596 16860 85.6596 17140 16350 85.6596 16620 85.6596 16870 85.6596 17150 16360 85.6596 16630 85.6596 16880 85.6596 17160 16370 85.6596 16640 85.6596 16890 85.6596 17170 16380 85.6596 16650 85.6596 16900 85.6596 17180 16390 85.6596 16660 85.6596 16910 85.6596 17190 16400 85.6596 16670 85.6596 16920 85.6596 17200 16410 85.6596 16680 85.6596 16930 85.6596 17210 16420 85.6596 16690 85.6596 16940 85.6596 17220 16430 85.6596 16700 85.6596 16950 85.6596 17230 16440 85.6596 16710 85.6596 16960 85.6596 17240 16450 85.6596 16720 85.6596 16970 85.6596 17250 16460 85.6596 16730 85.6596 16980 85.6596 17260 16470 85.6596 16740 85.6596 16990 85.6596 17270 16480 85.6596 16750 85.6596 17000 85.6596 17280 16490 85.6596 .16760 85.6596 17010 85.6596 17290 16500 85.6596 16770 85.6596 17020 85.6596 17300 16510 85.6596 16780 85.6596 17030 85.6596 17310 16520 85.6596 16770 85.6596 17050 85.6596 17320 16530 85.6596 16780 85.6596 17060 85.6596 17330 16540 85.6596 16790 85.6596 17070 85.6596 17340 16550 85.6596 16800 85.6596 17080 85.6596 17350 16560 85.6596 16810 85.6596 17090 85.6596 17360 16570 85.6596 16820 85.6596 17100 85.6596 17370 83 Table 18: Sorption Isotherm Values form 58 to 67% RH Time (min) Weight (9) Time (min) Weight (9) Time (min) Weight (9) Time (min) Weight (g) % 17380 85.6596 17830 86.2293 18280 86.31 18730 17390 85.6596 17840 86.2302 18290 86.3123 18740 17400 85.6596 17850 86.231 1 18300 86.3137 18750 17410 85.6596 17860 86.2319 18310 86.3151 18760 17420 85.6596 17870 86.2325 18320 86.3161 18770 17430 85.6596 17880 86.2331 18330 86.3162 18780 17440 85.6596 17890 86.2336 18340 86.3159 18790 17450 85.6596 17900 86.2345 18350 86.3151 18800 17460 85.6596 17910 86.2348 18360 86.3142 18810 17470 85.6596 17920 86.2356 18370 86.3122 18820 17480 85.6596 17930 86.2362 18380 86.31 13 18830 17490 85.6596 17940 86.2373 18390 86.3138 18840 17500 85.6596 17950 86.2382 18400 86.3144 18850 17510 85.7498 17960 86.2395 18410 86.3155 18860 17520 85.8535 17970 86.2407 18420 86.3171 18870 17530 85.9503 17980 86.242 18430 86.3181 18880 17540 86.0393 17990 86.2434 18440 86.3193 18890 17550 86.1227 18000 86.2453 18450 86.3196 18900 17560 86.1547 18010 86.2472 18460 86.3202 18910 17570 86.1774 18020 86.2487 18470 86.321 18920 17580 86.1923 18030 86.2501 18480 86.3215 18930 17590 86.1954 18040 86.2523 18490 86.321 1 18940 17600 86.1987 18050 86.2547 18500 86.3209 18950 17610 86.1995 18060 86.2561 18510 86.3208 18960 17620 86.2 18070 86.2581 18520 86.32 18970 17630 86.2158 18080 86.2605 18530 86.3197 18980 17640 86.2581 18090 86.2619 18540 86.3193 18990 17650 86.2653 18100 86.2639 18550 86.3184 19000 17660 86.2644 18110 86.2658 18560 86.317 19010 17670 86.2589 18120 86.2674 18570 86.316 19020 17680 86.2533 18130 86.2692 18580 86.3149 19030 17690 86.2477 18140 86.271 18590 86.314 19040 17700 86.243 18150 86.2731 18600 86.3135 19050 17710 86.2388 18160 86.2748 18610 86.3128 19060 17720 86.2357 18170 86.2758 18620 86.3128 19070 17730 86.2331 18180 86.2775 18630 86.3131 19080 17740 86.2309 18190 86.2799 18640 86.3129 19090 17750 86.2292 18200 86.2832 18650 86.3137 19100 17760 86.2284 18210 86.2864 18660 86.3149 19110 17770 86.2277 18220 86.2901 18670 86.3166 19120 17780 86.2273 18230 86.2932 18680 86.3183 19130 17790 86.2274 18240 86.2971 18690 86.3203 19140 17800 86.2278 18250 86.3007 18700 86.3228 19150 17810 86.2285 18260 86.304 18710 86.3257 19160 17820 86.229 18270 86.3068 18720 86.3275 19170 84 Time (min) Weight (9) Time (min) Weight (9) Time (min) Weight (9) Time (min) Weight (g) 19180 19190 19200 19210 19220 19230 19240 19250 19260 19270 19280 19290 19300 19310 19320 19330 19340 19350 19360 19370 19380 19390 19400 19410 19420 19430 19440 19450 19460 19470 19480 19490 19500 19510 19520 19530 19540 19550 19560 19570 19580 19590 19600 19610 19620 19630 19640 86.4602 86.4625 86.4645 86.4676 86.4703 86.4724 86.4748 86.4772 86.4799 86.4835 86.4869 86.4885 86.491 86.4931 86.4952 86.4973 86.4996 86.5022 86.5044 86.5062 86.5081 86.51 1 1 86.5131 86.5148 86.517 86.5195 86.522 86.5242 86.5266 86.5288 86.531 86.5336 86.5352 86.5366 86.537 86.5376 86.5389 86.5389 86.5389 86.5391 86.5388 86.5393 86.5381 86.5385 86.5388 86.539 86.5393 19660 19670 19680 19690 19700 19710 19720 19730 19740 19750 19760 19770 19780 19790 19800 19810 19820 19830 19840 19850 19860 19870 19880 19890 19900 19910 19920 19930 19940 19950 19960 19970 19980 19990 20000 20010 20020 20030 20040 20050 20060 20070 20080 20090 20100 20110 20120 86.5391 86.5406 86.5399 86.5399 86.5394 86.539 86.5394 86.5398 86.5409 86.5399 86.541 86.5413 86.5402 86.5415 86.5417 86.5417 86.5419 86.5408 86.5422 86.5419 86.5423 86.5409 86.5425 86.5425 86.5428 86.542 86.5421 86.5428 86.5431 86.5444) 86.5433 86.5421 86.5423 86.5425 86.5442 86.5445 86.5429 86.5431 86.5447 86.5445 86.5443 86.5438 86.5439 86.5449 86.5445 86.5443 86.5431 20130 20140 20150 20160 20170 20180 20190 20200 20210 20220 20230 20240 20250 20260 20270 20280 20290 20300 20310 20320 20330 20340 20350 20360 20370 20380 20390 20400 20410 20420 20430 20440 20450 20460 20470 20480 20490 20500 20510 20520 20530 20540 20550 20560 20570 20580 20590 86.5433 86.5432 86.5435 86.5437 86.5447 86.545 86.5441 86.5443 86.5444) 86.5439 86.5438 86.5446 86.5448 86.5441 86.5443 86.5445 86.5437 86.5435 86.544 86.5447 86.5448 86.545 86.5443 86.5447 86.5453 86.545 86.5449 86.5446 86.5443 86.5444 86.5439 86.544 86.5445 86.545 86.5452 86.5432 86.5438 86.5439 86.5445 86.5437 86.5429 86.542 86.5419 86.54 86.5387 86.5402 86.541 1 20600 20610 20620 20630 20640 20650 20660 20670 20680 20690 20700 20710 20720 20730 20740 20750 20760 20770 20780 20790 20800 20810 20820 20830 20840 20850 20860 20870 20880 20890 20900 20910 20920 20930 20940 20950 20960 20970 20980 20990 21000 21010 21020 21030 21040 21050 21060 85 Tlme (Min) Weight (g) Tlme (Min) Weight (g) Tlme (Min) Weight (9) Tlme (Min) Weight (9)“ 21080 21090 21100 21110 21120 21130 21140 21150 21160 21170 21180 21190 21200 21210 21220 21230 21240 21250 86.5487 86.551 1 86.5513 86.5508 86.5506 86.5509 86.5529 86.5527 86.5515 86.5503 86.5497 86.5496 86.5494 86.5501 86.5509 86.5509 86.5509 86.5515 21260 21270 21280 21290 21300 21310 21320 21330 21340 21350 21360 21370 21380 21390 21400 21410 21420 21430 86.5512 86.5513 86.5526 86.5526 86.5519 86.5487 86.5495 86.5498 86.5512 86.5513 86.5504 86.5509 86.5512 86.5522 86.5498 86.5468 86.5479 86.5488 21440 21450 21460 21470 21480 21490 21500 21510 21520 21530 21540 21550 21560 21570 21580 21590 21600 21610 86.5497 86.5512 86.5513 86.5505 86.5509 86.5512 86.5512 86.5515 86.5517 86.552 86.5514 86.5525 86.5513 86.5514 86.5524 86.5549 86.5504 86.5506 21620 21630 21640 21650 21660 21670 21680 21690 21700 21710 21720 21730 21740 21750 21760 21770 21780 21780 86 Table 19: Sorption Isotherm Values from 67 to 75% RH Time (min) Weight (9) Time (min) Weight (9) Time (min) Weight (9) Time (min) Weight (9) 21790 86.5528 22240 86.9848 22690 87.0939 23140 87.138 21800 86.553 22250 86.99 22700 87.096 23150 87.1399 21810 86.5766 22260 86.9939 22710 87.0975 23160 87.1409 21820 86.6147 22270 86.9994 22720 87.0992 23170 87.1421 21830 86.6501 22280 87.0024 22730 87.1014 23180 87.144 21840 86.6815 22290 87.0057 22740 87.1031 23190 87.1455 21850 86.5569 22300 87.008 22750 87.1048 23200 87.1437 21860 86.5856 22310 87.0115 22760 87.1053 23210 87.1455 21870 86.6124 22320 87.0146 22770 87.1074 23220 87.1471 21880 86.6361 22330 87.018 22780 87.1071 23230 87.1467 21890 86.6574 22340 87.0209 22790 87.1084 23240 87.1444 21900 86.6775 22350 87.0237 22800 87.1083 23250 87.1483I 21910 86.6959 22360 87.027 22810 87.1089 23260 87.1515 21920 86.7133 22370 87.0295 22820 87.1 102 23270 87.1527 21930 86.7286 22380 87.0323 22830 87.1 1 19 23280 87.1535 21940 86.745 22390 87.035 22840 87.1 129 23290 87.1545 21950 86.7585 22400 87.037 22850 87.1 138 23300 21960 86.7716 22410 87.0388 22860 87.1 144 23310 21970 86.785 22420 87.0426 22870 87.1 146 23320 21980 86.7968 22430 87.0449 22880 87.1 15 23330 21990 86.8086 22440 87.0468 22890 87.1 157 23340 22000 86.8198 22450 87.0494 22900 87.1 162 23350 22010 86.8303 22460 87.0507 22910 87.1 167 23360 22020 86.839 22470 87.0528 22920 87.0432 23370 22030 86.8494» 22480 87.0557 22930 87.0819 23380 22040 86.8593 22490 87.0556 22940 87.1 1 16 23390 22050 86.8684 22500 87.06 22950 87.1207 23400 22060 86.8762 22510 87.0621 22960 87.1244 23410 22070 86.8842 22520 87.061 22970 87.1268 23420 22080 86.8938 22530 87.0629 22980 87.1267 23430 22090 86.8984 22540 87.0645 22990 87.1283 23440 22100 86.9067 22550 87.0664 23000 87.1293 23450 221 10 86.914 22560 87.0689 23010 87.1301 23460 22120 86.9209 22570 87.0712 23020 87.1303 23470 22130 86.9282 22580 87.0725 23030 87.1303 23480 22140 86.9342 22590 87.0743 23040 87.1312 23490 22150 86.9402 22600 87.0766 23050 87.1308 23500 22160 86.9462 22610 87.0784 23060 87.1313 23510 22170 86.9518 22620 87.0808 23070 87.1323 23520 22180 86.9576 22630 87.0833 23080 87.1327 23530 22190 86.9632 22640 87.0847 23090 87.1338 23540 22200 86.968 22650 87.0862 23100 87.1346 23550 22210 86.9728 22660 87.0884 23110 87.1355 23560 22220 86.9714 22670 87.0905 23120 87.1365 23570 22230 86.9787 22680 87.0927 23130 87.1375 23580 87 Time (min) Weight (9) Time (min) Weight (9) Time (min) Weight (9) Time (min) Weight (9111 23140 23150 23160 23170 23180 23190 23200 23210 23220 23230 23240 23250 23260 23270 23280 23290 23300 23310 23320 23330 23340 23350 23360 23370 23380 23390 23400 23410 23420 23430 23440 23450 23460 23470 23480 23490 23500 23510 23520 23530 23540 23550 23560 23570 23580 23590 23600 87.1384 87.1399 87.1409 87.1421 87.144 87.1455 87.1437 87.1455 87.1471 87.1467 87.1444) 87.1483 87.1515 87.1527 87.1535 87.1545 87.155 87.155 87.1559 87.1577 87.1585 87.1588 87.1602 87.1605 87.1622 87.1636 87.1645 87.1654 87.166 87.1665 87.1674 87.1684 87.1695 87.1714 87.1727 87.174 87.1752 87.1763 87.1768 87.1777 87.1795 87.1813 87.1817 87.1824 87.1847 87.1862 87.1875 23630 23640 23650 23660 23670 23680 23690 23700 23710 23720 23730 23740 23750 23760 23770 23780 23790 23800 23810 23820 23830 23840 23850 23860 23870 23880 23890 23900 23910 23920 23930 23940 23950 23960 23970 23980 23990 24000 24010 24020 24030 24040 24050 24060 24070 24080 24090 87.191 87.1915 87.1928 87.1937 87.1943 87.1952 87.1971 87.2004 87.2001 87.2017 87.2027 87.2035 87.2047 87.2056 87.2064 87.2068 87.2078 87.2091 87.2098 87.21 12 87.2123 87.2134 87.2143 87.2155 87.2167 87.2186 87.219 87.2194 87.2215 87.222 87.2221 87.2232 87.2238 87.2249 87.2253 87.2254 87.2259 87.2263 87.2277 87.2281 87.229 87.2302 87.2319 87.2327 87.234 87.2356 87.2371 24110 24120 24130 24140 24150 24160 24170 24180 24190 24200 24210 24220 24230 24240 24250 24260 24270 24280 24290 24300 24310 24320 24330 24340 24350 24360 24370 24380 24390 24400 24410 24420 24430 24440 24450 24460 24470 24480 24490 24500 24510 24520 24530 24540 24550 24560 24570 87.2385 87.2403 87.2417 87.2427 87.2434 87.2437 87.2445 87.2455 87.2451 87.2459 87.2471 87.2476 87.2484 87.2491 87.2491 87.2506 87.2514 87.2528 87.2539 87.2545 87.2562 87.2576 87.2581 87.2594 87.2609 87.2631 87.2619 87.2641 87.2658 87.2671 87.2684 87.2682 87.27 87.2715 87.2731 87.2739 87.2755 87.2767 87.2778 87.2785 87.2798 87.2791 87.2803 87.2814 87.2834 87.284 87.2848 24590 24600 24610 24620 24630 24640 24650 24660 24670 24680 24690 24700 24710 24720 24730 24740 24750 24760 24770 24780 24790 24800 24810 24820 24830 24840 24850 24860 24870 24880 24890 24900 24910 24920 24930 24940 24950 24960 24970 24980 24990 25000 25010 25020 25030 25040 25050 87.2869 87.288 87.2887 87.2897 87.2908 87.292 87.2928 87.2931 87.2949 87.2957 87.2958 87.2972 87.2977 87.297 87.2991 87.3002 87.3014 87.302 87.3042 88 Time (min) Weight (9) Time (min) Weight (9) Time (min) Weight (9) Time (min) Weight (g) 25070 25080 25090 25100 25110 25120 25130 25140 25150 25160 25170 25180 25190 25200 25210 25220 25230 25240 25250 25260 25270 25280 25290 25300 25310 25320 25330 25340 25350 25360 25370 25380 25390 25400 25410 25420 25430 25440 25450 25460 25470 25480 25490 25500 25510 25520 25530 25540 87.3291 87.3298 87.3303 87.3308 87.3314 87.331 1 87.3324 87.3334 87.3338 87.3338 87.3336 87.3328 87.3342 87.3351 87.335 87.3352 87.3352 87.3355 87.3355 87.3355 87.3367 87.3375 87.3368 87.3537 87.3534 87.3533 87.3529 87.3523 87.3535 87.3509 87.3518 87.3508 87.3489 87.3493 87.3476 87.346 87.345 87.3442 87.3586 87.358 87.3573 87.356 87.359 87.3631 87.3641 87.3636 87.3649 87.3652 25560 25570 25580 25590 25600 25610 25620 25630 25640 25650 25660 25670 25680 25690 25700 25710 25720 25730 25740 25750 25760 25770 25780 25790 25800 25810 25820 25830 25840 25850 25860 25870 25880 25890 25900 25910 25920 25930 25940 25950 25960 25970 25980 25990 26000 26010 26020 26030 87.3673 87.368 87.3679 87.3687 87.3686 87.3682 87.3671 87.367 87.3674 87.3674 87.3666 87.3667 87.367 87.3678 87.3673 87.3671 87.3682 87.3696 87.3694 87.3704 87.3713 87.3716 87.3717 87.372 87.3736 87.3738 87.3744 87.3756 87.3752 87.3763 87.375 87.3761 87.3781 87.3781 87.3786 87.3796 87.3802 87.3806 87.3813 87.3817 87.3822 87.3836 87.3839 87.3849 87.3871 87.3874 87.3872 87.3891 26040 26050 26060 26070 26080 26090 26100 26110 26120 26130 26140 26150 26160 26170 26180 26190 26200 26210 26220 26230 26240 26250 26260 26270 26280 26290 26300 26310 26320 26330 26340 26350 26360 26370 26380 26390 26400 26410 26420 26430 26440 26450 26460 26470 26480 26490 26500 26510 87.3896 87.3914 87.3917 87.393 87.3932 87.3939 87.3943 87.3952 87.3955 87.3957 87.3971 87.3985 87.3993 87.3995 87.3994 87.4 87.4002 87.4005 87.3998 87.401 87.402 87.4028 87.4051 87.4058 87.4067 87.409 87.4096 87.4096 87.4103 87.41 13 87.41 16 87.4125 87.4145 87.416 87.4164 87.4179 87.4184 87.4174 87.4178 87.4173 87.4181 87.4174 87.4181 87.4174 87.4187 87.4195 87.4187 87.4179 26520 26530 26540 26550 26560 26570 26580 26590 26600 26610 26620 26630 26640 26650 26660 26670 26680 26690 26700 26710 26720 26730 26740 26750 26760 26770 26780 26790 26800 26810 26820 26830 26840 26850 26860 26870 26880 26890 26900 26910 26920 26930 26940 26950 26960 26970 26980 26990 89 Time (min) Weight (9) Time (min) Weight (9) Time (min) Weight (9) Time (min) Weight (g) 27000 27010 27020 27030 27040 27050 27060 27070 27080 27090 27100 27110 27120 27130 27140 27150 27160 27170 27180 27190 27200 27210 27220 27230 27240 27250 27260 27270 27280 27290 27300 27310 27320 27330 27340 27350 27360 27370 27380 27390 27400 27410 27420 27430 27440 27450 27460 27470 87.461 87.4629 87.4634 87.4668 87.4683 87.4693 87.4697 87.4706 87.4718 87.4741 87.4773 87.4757 87.4798 87.4797 87.4738 87.4794 87.4805 87.4823 87.4842 87.4845 87.4888 87.4894 87.4907 87.492 87.4937 87.4904 87.4919 87.4909 87.4941 87.4956 87.497 87.4999 87.5014 87.5058 87.5043 87.5098 87.5123 87.51 17 87.5147 87.5251 87.5315 87.5335 87.5345 87.5354 87.5361 87.5355 87.5359 87.5367 27490 27500 27510 27520 27530 27540 27550 27560 27570 27580 27590 27600 27610 27620 27630 27640 27650 27660 27670 27680 27690 27700 27710 27720 27730 27740 27750 27760 27770 27780 27790 27800 27810 27820 27830 27840 27850 27860 27870 27880 27890 27900 27910 27920 27930 27940 27950 27960 87.5385 87.5413 87.5422 87.5429 87.5452 87.5466 87.5466 87.5486 87.5507 87.5519 87.5525 87.5544 87.5549 87.5553 87.5571 87.5558 87.5557 87.556 87.5586 87.558 87.5572 87.5576 87.5583 87.5599 87.5576 87.5559 87.5527 87.549 87.5432 87.5369 87.5292 87.5182 87.5104 87.5046 87.5049 87.4985 87.4868 87.4763 87.4675 87.4617 87.4544 87.4484 87.4433 87.4445 87.484 87.5523 87.6229 87.5874 27970 27980 27990 28000 28010 28020 28030 28040 28050 28060 28070 28080 28090 28100 28110 28120 28130 28140 28150 28160 28170 28180 28190 28200 28210 28220 28230 28240 28250 28260 28270 28280 28290 28300 28310 28320 28330 28340 28350 28360 28370 28380 28390 28400 28410 28420 28430 28440 87.5743 87.5893 87.5635 87.5615 87.5492 87.5546 87.5584 87.5481 87.5442 87.5462 87.5891 87.5871 87.5457 87.5507 87.5533 87.5478 87.5424 87.5568 87.5447 87.5406 87.5596 87.5552 87.5596 87.5541 87.5587 87.5575 87.5509 87.5515 87.5506 87.5503 87.5526 87.5516 87.5534 87.5537 87.5529 87.5519 87.5508 87.5506 87.5489 87.5487 87.5499 87.5535 87.554 87.5523 87.5514 87.5516 87.5528 87.5516 28450 28460 28470 28480 28490 28500 28510 28520 28530 28540 28550 28560 28570 28580 28590 28600 28610 28620 28630 28640 28650 28660 28670 28680 28690 28700 28710 28720 28730 28740 28750 28760 28770 28780 28790 28800 28810 28820 28830 28840 28850 28860 28870 28880 28890 28900 28910 28920 87.5767 87.5542 87.5551 87.5562 9O Time (min) Weight (9) Time (min) Weight (9) Time (min) Weight (9) Time (min) Weight (9)1 27480 28930 28940 28950 28960 28970 28980 28990 29000 29010 29020 29030 29040 29050 87.5366 87.5512 87.5516 87.5555 87.5502 87.5497 87.5489 87.5476 87.5487 87.5499 87.5513 87.5521 87.5519 87.5515 29050 29060 29070 29080 29090 29100 29110 29120 29130 29140 29150 29160 29170 29180 87.5515 87.5504 87.551 87.5514 87.5523 87.5523 87.5567 87.5534 87.55 87.5459 87.5455 87.5468 87.5613 87.5442 29190 29200 29210 29220 29230 29240 29250 29260 29270 29280 29290 29300 29310 29320 87.5451 87.5455 87.5469 87.5471 87.5479 87.5478 87.548 87.5459 87.5406 87.5412 87.5433 87.5423 87.5468 87.5359 29330 29340 29350 29360 29370 29380 29390 29400 29410 29420 29430 29440 29450 29450 87.5248 87.5245 87.5156 87.5145 87.5109 87.52 87.5203 87.5188 87.5188 87.5232 87.5199 87.523 87.523 87.523 9] Table 20: Sorption Isotherm Values from 75 to 85 % RH Time (min) Weight (9) Time (min) Weight (9) Time (min) Weight (9) Time (min) Weight (9)" 29460 87.5407 29910 88.0881 30360 88.2067 30810 29470 87.5625 29920 88.089 30370 88.2089 30820 29480 87.5846 29930 88.095 30380 88.2275 30830 29490 87.6062 29940 88.103 30390 88.2384 30840 29500 87.6264 29950 88.108 30400 88.2497 30850 29510 87.6463 29960 88.115 30410 88.2508 30860 29520 87.6662 29970 88.125 30420 88.2555 30870 29530 87.6864 29980 88.1267 30430 88.2587 30880 29540 87.7039 29990 88.1269 30440 88.2604 30890 29550 87.7224 30000 88.1281 30450 88.2631 30900 29560 87.7394 30010 88.1286 30460 88.2644 30910 29570 87.7571 30020 88.129 30470 88.2668 30920 29580 87.7746 30030 88.1299 30480 88.2694 30930 29590 87.7922 30040 88.1356 30490 88.2715 30940 29600 87.81 1 30050 88.1386 30500 88.2734 30950 29610 87.8294 30060 88.1394 30510 88.2756 30960 29620 87.8464 30070 88.1427 30520 88.2768 30970 29630 87.8659 30080 88.1466 30530 88.2787 30980 29640 87.8855 30090 88.1489 30540 88.28 30990 29650 87.9061 30100 88.1502 30550 88.2834 31000 29660 87.9229 301 10 88.155 30560 88.2848 31010 29670 87.9423 30120 88.1576 30570 88.2864 31020 29680 87.961 1 30130 88.1586 30580 88.2897 31030 29690 87.9787 30140 88.1594 30590 88.2912 31040 29700 87.9973 30150 88.1606 30600 88.2934 31050 29710 88.0123 30160 88.1616 30610 88.2954 31060 29720 88.0282 30170 88.1643 30620 88.2967 31070 29730 88.0415 30180 88.1675 30630 88.3541 31080 29740 88.052 30190 88.1685 30640 88.3865 31090 29750 87.9937 30200 88.1694 30650 88.3941 31 100 29760 88.052 30210 88.1705 30660 88.3987 31110 29770 88.0735 30220 88.1728 30670 88.4012 31 120 29780 88.0828 30230 88.1765 30680 88.4039 31 130 29790 88.0829 30240 88.18 30690 88.4085 31140 29800 88.0834 30250 88.1833 30700 88.4152 31 150 29810 88.0844 30260 88.1864 30710 88.4199 31160 29820 88.0846 30270 88.1891 30720 88.4268 31 170 29830 88.0847 30280 88.1903 30730 88.43 31 180 29840 88.0853 30290 88.1909 30740 88.4368 31 190 29850 88.0856 30300 88.1925 30750 88.4389 31200 29860 88.0858 30310 88.1945 30760 88.4401 31210 29870 88.0864 30320 88.1968 30770 88.4425 31220 29880 88.0868 30330 88.1999 30780 88.4468 31230 29890 88.0872 30340 88.203 30790 88.4494 31240 29900 88.0877 30350 88.2045 30800 88.4532 31250 92 Time (min) Weight (9) Time (min) Weight (9) Time (min) Weight (9) Time (min) Weight (g) 31260 31270 31280 31290 31300 31310 31320 31330 31340 31350 31360 31370 31380 31390 31400 31410 31420 31430 31440 31450 31460 31470 31480 31490 31500 31510 31520 31530 31540 31550 31560 31570 31580 31590 31600 31610 31620 31630 31640 31650 31660 31670 31680 31690 31700 31710 31720 31730 88.6223 88.6299 88.6378 88.6435 88.6522 88.6734 88.6886 88.6989 88.7086 88.7203 88.7259 88.7399 88.7506 88.761 1 88.7695 88.7777 88.7813 88.7892 88.7905 88.7986 88.8781 88.8806 88.8894 88.8902 88.8956 88.8995 88.9056 88.9154 88.9232 88.9279 88.9328 88.9386 88.9489 88.9515 88.9588 88.9623 88.9666 88.9746 88.9778 88.9806 88.9868 88.9897 88.9925 88.9958 88.9986 89.0021 89.0102 89.0187 31750 31760 31770 31780 31790 31800 31810 31820 31830 31840 31850 31860 31870 31880 31890 31900 31910 31920 31930 31940 31950 31960 31970 31980 31990 32000 32010 32020 32030 32040 32050 32060 32070 32080 32090 32100 32110 32120 32130 32140 32150 32160 32170 32180 32190 32200 32210 32220 89.0345 89.0456 89.0555 89.0597 89.0689 89.0756 89.0897 89.0953 89.0995 89.1052 89.1 103 89.1 175 89.1 194 89.1242 89.1305 89.1309 89.1315 89.13189 89.1326 89.133 89.1335 89.1338 89.1342 89.1345 89.1357 89.1364 89.1368 89.1374 89.1376 89.1379 89.1384 89.1387 89.1392 89.1393 89.1396 89.1399 89.1402 89.1406 89.1411 89.1415 89.1417 89.142 89.1423 89.1425 89.1427 89.143 89.1432 89.1435 32230 32240 32250 32260 32270 32280 32290 32300 32310 32320 32330 32340 32350 32360 32370 32380 32390 32400 32410 32420 32430 32440 32450 32460 32470 32480 32490 32500 32510 32520 32530 32540 32550 32560 32570 32580 32590 32600 32610 32620 32630 32640 32650 32660 32670 32680 32690 32700 89.1437 89.1439 89.1441 89.1447 89.1453 89.1528 89.1593 89.1691 89.1758 89.1812 89.1867 89.1935 89.1973 89.2023 89.208 89.212 89.2182 89.2229 89.2284 89.2345 89.241 89.2443 89.2498 89.2563 89.2639 89.2698 89.2746 89.2786 89.2828 89.2866 89.2903 89.2962 89.2995 89.3043 89.31 89.3126 89.3149 89.3181 89.3182 89.3183 89.3184 89.3185 89.3185 89.3185 89.3186 89.3186 89.3186 89.3186 32710 32720 32730 32740 32750 32760 32770 32780 32790 32800 32810 32820 32830 32840 32850 32860 32870 32880 32890 32900 32910 32920 32930 32940 32950 32960 32970 32980 32990 33000 33010 33020 33030 33040 33050 33060 33070 33080 33090 33100 33110 33120 33130 33140 33150 33160 33170 33180 89.3187 89.3187 89.3187 89.3187 89.3187 89.3187 89.3187 89.3187 89.3191 89.3191 89.3191 89.3191 89.3191 89.3191 89.3191 89.3191 89.3191 89.3192 89.3192 89.3192 89.3192 89.3192 89.3192 89.3192 89.3192 89.3192 89.3192 89.3192 93 Time (min) Weight (9) Time (min) Weight (9) Time (min) Weight (9) Time (min) Weight (g) 33190 33200 33210 33220 33230 33240 33250 33260 33270 33280 33290 33300 33310 33320 33330 33340 33350 33360 33370 33380 33390 33400 33410 33420 33430 33440 33450 33460 33470 33480 89.3192 89.3192 89.3193 89.3193 89.3193 89.3193 89.3193 89.3193 89.3193 89.3193 89.3193 89.3192 89.3192 89.3192 89.3192 89.3192 89.3192 89.3192 89.3192 89.3192 89.3191 89.3191 89.3191 89.3191 89.3191 89.319 89.319 89.319 89.319 89.319 33490 33500 33510 33520 33530 33540 33550 33560 33570 33580 33590 33600 33610 33620 33630 33640 33650 33660 33680 33690 33700 33710 33720 33730 33740 33750 33760 33770 33780 33790 89.319 89.319 89.319 89.319 89.3189 89.3189 89.3189 89.3189 89.3189 89.3188 89.3188 89.3188 89.3188 89.3188 89.3188 89.3188 89.3187 89.3187 89.3189 89.319 89.319 89.3191 89.3193 89.319 89.3187 89.3188 89.3185 89.3188 89.3189 89.319 33800 33810 33820 33830 33840 33850 33860 33870 33880 33890 33900 33910 33920 33930 33940 33950 33960 33970 33980 33990 34000 34010 34020 34030 34040 34050 34060 34070 34080 34090 89.3195 89.3194 89.3198 89.3199 89.3199 89.3199 89.32 89.32 89.32 89.32 89.32 89.32 89.32 89.32 89.32 89.32 89.32 89.32 89.32 89.32 89.32 89.32 89.32 89.32 89.32 89.32 89.32 89.321 89.321 89.321 34100 34110 34120 34130 34140 34150 34160 34170 34180 34190 34200 34210 34220 34230 34290 34300 34310 34320 34330 34340 34350 34360 34370 34380 34380 34380 34380 34380 34380 34380 89.321 89.321 89.321 89.321 89.321 89.321 89.321 89.321 89.321 89.321 89.321 89.321 89.321 89.321 89.321 89.321 89.321 89.321 89.321 89.321 89.321 89.321 89.321 89.321 89.321 89.321 89.321 89.321 89.321 89.321 94 APPENDIX F Plot of The sorption Isotherms Values under Various Humidities tested by Cahn Electrobalance '3 5 E .E’ o 3 8889888 Cahnlnsmmm Sorption Isotherms T a . KAI;— l l s/flf ' /"—-———-( 67% 1 i 43% 55% 5.7% m" 4 A A l l k L 1 I 30 7330 10330‘K§§X)16330‘HN§K)22330JZ§§I32833013H§KJ34330 Tenperame EC Time (min) _—4_W~_._4 BIBLIOGRAPHY Anonymous, "Guide to Plastics", MOdern Plastic, Hill Mcgraw, NY., 1987, pp. 57 Baer, Eric, "Thermal Stability", Engineering Design for Plastics, Polymer and Engineering Series, 1964, pp. 401-403. Baner, A.L.(III); Hernandez, R.J.; Krishnamurthy, J.; Giacin, J.R., "Isostatic and Quasi—Isostatic Methods for Determining the Permeability of Organic Vapors Through Barrier Membranes." Current Technologies in Flexible Packaging, ASTM STP 912, M.L. Troedel, Ed., American Society for Testing and Materials, Philadelphia, 1986, 49—62. Blatz, Philip S., E.I. duPONT de NEMOURS & Co., Inc., " Properties of Film From Blends of Amorphous and Crystalline Nylons", Innovationsin Polyamide Technology, Aiche.Meeting, April 2-6, 1989, Houston, Texas. 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