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T this symbiotic relationship, permeability of organic compounds must be an integral part of the package design process. At this time a comprehensive database of permeability is not available. The creation of a comprehensive database will enable the product/package designer to optimize quality' and functionality' while simultaneously Ininimizing cost. For example, this database would 1x3 useful in the design of various products containing volatile, organic constituents, such as confectionary products, beverages, flavored dairy products, soups, and culinary products. Because a database of this nature needs to be flexible in design auui of considerable magnitude, ii: is necessary to approach this project in several stages. The objective (n? this thesis is 11> create a comprehensive database using Microsoft Access 97 coupled with Visual Basic for Application programming to compile permeability data which would be readily accessible to technical product/packaging professionals. The proposed database would serve as a design, quality, and safety tool, allowing for estimation of the degree of flavor loss which could be expected from a given product/package system design. Zobel Copious amounts of research. pertaining' to saturated vapons has been published since 1948. While this work is useful in estimating how well a package will withstand an accidental high level of contamination, it is not an authentic use of data to estimate permeation rates because of the considerably lower levels of vapor encountered in a retailing situation Zobel (1982). In response to this determination, Zobel devised an isostatic technique coupled with a flame ionization detector. This methodology is partially' based (N1 the work; of Niebergal's (1978) sophisticated method. Since Zobel suggested that real life situations would require vapor concentrations down to 1 ppm, he chose to use a flame ionization technique as his detection method. The flame ionization method assured the possibility of measuring within these lOW'Ixxn vapor concentration ranges which the pmevious vapor sampling methods did not. However, the flame ionization detector is limited to simple test vapors; therefore, i1: cannot kxa used tx> test complex natural odors. Later, Zobel. (1984) :modified tflua detection 'technique by incorporating a sorption desorption cycle before the test vapor entered the detector. This resulted in an increase in detection accuracy because it improved discrepancy between a real signal and a baseline drift when testing' at the ‘more "realistic" low vapor concentration levels. 'At these low vapor concentration levels, permeability' became 'virtually' constant, allowing for possible extrapolation.afl: even lower levels. Zobel (1984) concluded that the results showed that the rate of change of permeability coefficient with concentration was small provided that the odorant was kept below 10% of the saturated vapor pressure. Gilbert Gilbert, the Head cm? the Rutgers Food Science Department, is another significant contributor to the science of mass transfer. The famous paper by Gilbert and Pegaz (1969) is a milestone in this area of science. The quasi isostatic procedure utilizing a gas chromatograph equipped with a flame ionization detector was developed and reviewed. As recent as 1987, Gilbert uses this quasi isostatic procedure, and it is the platform which Baner and Hernandez from Michigan State's School of Packaging based their quasi-isostatic methodology on in the mid-805. Gilbert was a strong believer in pre—conditioning the samples before testing; and he reported all results after gelbo flex testing the film samples for 20 cycles as stated in ASTM F>392-74 adding another dimension to the results. In the case of flexed glassine, the extremely high values are attributed to the presence of pinholes or macro voids in the film which sharply increase the permeation rate. An exception to the normal increased permeability of flexed films was found. PE/NYLON/PE responded positively to flexing by decreasing the permeability values. This can be attributed to orientation of polymer chains on flexing with consequent increase 1J1 "packing" of tflmxxa macromolecules Gilbert and a1. (1987). Allied, a nylon film converter, established a collaborative study with Gilbert. The results of the study include an interesting quantitative to qualitative analysis for determining if a particular polymer/penetrant combination was excellent, good, or poor. The results are as follows and are based on permeability units of gyums o . , at 70 F, Gilbert 5 standard. measurement of 24hrs*m2*1 OOppm permeability. An excellent rating was conferred on polymer/penetrant combinations with 0.1 or less permeability, good in the range of 0.1 to 1, and poor for any polymer/penetrant combination over 1. The film materials tested. included; nylon, polyvinylidene chloride (PVDC), ethyl vinyl alcohol(EVOH), and. glassine McKinley (1984). The results indicate that nylon provides good to excellent protection against the permeation of flavors and aromas, and offers the most economical barrier per-mil thickness. In addition, nylon provides excellent grease, and oil resistance, and high temp performance, as well as impact puncture and tear resistance. Coextruded films with thin nylon cores proved to have the broadest range of performance properties of the films tested. with optimum flavor and aroma barrier McKinley (1984). In 1987 Gilbert conducted another extensive lamination study. The effect of water interacting with nylon laminations was studied” Nylon, a hydrophobic material containing hydrogen kxnuka acts adversely when ij1 contact with water, causing the polymer matrix to swell; this results in film platicization and an increase in permeability. However, Gilbert discovered that with proper laminations which protect the nylon from outside conditions by ‘utilizing e1 polyolefin. layer‘ this plasticizing' effect could 1x3 nearly' eliminated. Consequently, ii: was found that the best barrier properties at both 0% RH and 75% RH were awarded tx> the nylon and pmdyethylene vinyl alcohol laminations rather tfluni the PET—G anui polyvinylidene chloride (PVDC) laminations. It should be noted that Gilbert developed. a runv set. of ‘test cells: one for low barrier testing, and one for high barrier Gilbert (1987). DeLausses DeLausses, gnu engineer for tflua Dow Chemical company, has established another isosatic testing method for determining the Inass ‘transfer characteristics of ‘various organic polymer/penetrant combinations. Polymer penetrant combinations cannot reliably be ranked by their oxygen permeabilities DeLausses (1994). DeLausses claims many packaging engineers unfortunately have this ndsconception. Permeability has consistently been reported as ea modified . kg*m —20 . . . Zobel unit, or 81 (—2——) Wlth the logic being to m*sec*Pa simplify reporting of permeability. In his earlier testing DeLausses used a photoionization detector to quantify polymer/penetrant mass transfer data. Later, it was determined that photoionization detectors were not as accurate as initially thought. The potential coating of the window of the photoionization detector from permeating molecules proved to reduce sensitivity. DeLausses(1994) did a case study seeking to understand the importance of barrier layer placement for both rigid containers and thin films in aroma barrier packaging. [F limonene was used as the model flavor component establishing an interest in keeping the flavor in the package, instead of studying the adverse affects of a volatile migrating into the package. The barrier layer on the inside for both the rigid container and thin film greatly reduced the permeability of d—limonene through the package. This can 1x3 attributed 13) the increased. time needed tx> saturate the barrier layer CH1 the inside since the diffusivity is very low as opposed to the barrier on the outside where the d—limonene would diffuse much more rapidly, inadvertently increasing permeation. Once again, it was found that EVOH permeability and diffusivity can be up to 1000 times greater for flavor and aroma mass transport when subjected to high humidity than under dry conditions. This same study also displayed the lack of sensitivity of vinylydene chloride to high levels of humidity compared with dry conditions. Later, DeLausses (1988), used a novel mass spectrometer as the means of detection of aromas/volatiles in all tests. This detection system was chosen so that the user could evaluate the effect of multiple mixtures of organic penetrants, an option not available with the popular flame ionization detection method. A study was undertaken by Dow to determine the applicability' of aroma barrier properties for its Saran (PVDC) film. DeLausses found that the permeability of aromas was up to 9000 times lower than in polyolefins. DeLausses interestingly noted that the solubility coefficients were found to be similar in magnitude. DeLausses also utilized an equation for predicting the permeabilities (If various compounds an: different temperatures. This equation has proved useful because investigators are increasingly testing higher barrier materials which require increased test temperatures to bring permeability measurements within detection range of mass spectrometers. This is necessary in order to increase both the diffusion and permeability coefficient, thus keeping test times reasonable. It should. also kxa noted. that DeLausses specifically mentioned the inability to Lhfi? this temperature dependent equation through Tg cm: with polymer/penetrant combinations which strongly' react, and/or' glassy' polymers. In. other words, caution should be used when utilizing this equation. A simple explanation of the mass spectrometer unit used in 1988 is as follows: It could be programmed to look for the most populous ion fragments of the permeant. Multiple permeants could be tested simultaneously by avoiding significant degeneracies when selecting ion fragments for monitoring. The response could be monitored and stored for later analysis. The importance of using a 10 partial pressure gradient more true tx> lifle was emphasized DeLausses (1988). In a later study, DeLausses (1990) defined the necessary improvement of flavor/volatile testing in relation to inorganic substances. It is known that vegetable and tomato sauces can only tolerate 1—5 ppm oxygen loss on a wt/wt loss. There is a much smaller flavor movement allowed. Often a few parts per billion of flavor are enough to change the taste or smell of a food. ID: was discovered 1J1 this project that 13/ using the flow through hollow fiber probe, parts per billion sensitivity can be reached for monitoring volatile organics in air (n: nitrogen. 'This sensitivity increase allows the use of conventional electron impact for aroma/flavor permeation measurements. The electron impact mass spectrometer is known for its wider dynamic range, broader range of application to a variety of chemicals, and more commercial availability. It should be noted that this technique could be used to test below ambient temperatures, another advantage over previously used units DeLausses (1990) Zobel's (1982) earlier flame ionization technique was found to be accurate to 3 * 10'12 kg * Hf2* sec‘R ll Giacin, Hernandez, Baner Mass Transfer, as it relates to packaging issues, has been studied an: The School of Packaging, Michigan State University, for many years. Dr. Jack Giacin, and Dr. Ruben Hernandez have established one of the most well known labs for the advancement of this scientific quest. Giacin (1981) developed a quasi-isostatic procedure utilizing a "snoopy" detector, which was based on decreased electrical resistance of the sensing element. The "snoopy" detector was deemed to have sensitivity similar to the popular flame ionization detector; 'The difference between the upper and lower cell sensors determined the transmission rate. Permeability was calculated from this result by incorporating the carrier gas flow rate, and permeation concentration at steady state. LDPE with isopropanol was tested under constant 23%: with aa partial pressure gradient of 28.5 ppm wt/v. Giacin, at this time, * . reported permeability in 2 gmlmd . m *24hr*mmI-Ig Baner (1984) reviewed the concept of concentration dependencies. for jpermeability' and :model petroleum substances. The study cflf this parameter identifies the investigator. as interested in the migration of harmful substances from tjua outside environment into time product, as opposed to the transfer of a flavor simulated by another chosen organic penetrant in relation tx> its mass transfer parameters for a specific polymer. This particular study also defines a series of equations to mathematically model mass transfer parameters and their use. These equations are valid only when the system follows fickian type behavior, a phenomenon frequently not upheld in many organic penetrant/polymer systems. Hernandez (1984) has also determined that between 23- 60°C the behavior of the polymer/penetrant system changes from fickian to non-fickian for the toluene/PET system 13 studied. The completion of this database can be a valuable tool useful in determining how the transition from fickian to non—fickian behavior occurs, whether gradual or dramatic. Threshold is defined as ea situation where no permeation has occurred at a given temperature and partial pressure gradient for 51 specific ;polymer/pentrant system after the period.cflf 6 months. Hernandez (1984) determined that there exists a 76 ppm threshold for PET/toluene at 23%: Two methods were utilized to determine the effects of water on the permeability of toluene vapor through a multi— layer film. containing hydrophilic layers Liu, Hernandez, Giacin (1986). The testing of tflua mass transport characteristics of a multi-component mixture through a high barrier polymer proved too much for the automated sampling of the isostatic system. The testing of high barrier material greatly increased the time to reach steady state. This can be attributed to the difficulties associated with keeping a constant partial pressure gradient over an extended period of time, an attribute the quasi-isostatic system was not plagued with. Permeance was measured in (g * structure * 10 2) 2 ). Permeance over permeability is the .m *dmflHOORmm l4 desired measurement for any multilayer structure due to the unpredictable nature anui many ‘times unknown 'thickness of the various layers (Hf the structure. The polymer tested was a multi-layer structure consisting of PE/Nylon/EVAL/Nylon/PE. All tests were conducted at 23°C. Method I consisted of pre-conditioning the samples at a specified. humidity' for the test until equilibriunt was reached” .At that point the samples were moved to the permeability 'testing' apparatus and .affixed. The organic penetrant, 1J1 this case, toluene, was flowed ij1ea carrier gas, N2, along with a relative humidity level set to duplicate the pre-conditioning of the film. Method 11 pre-conditioned the film over desiccant, effectively eliminating nmisture. Afterwards, Tina sample was affixed to the permeation cell where it was flowed with the organic penetrant kept at desired relative humidity level. This test evaluates the effect of water vapor as a co—permeant to toluene, the organic volatile penetrant. The permeability of nmlti-component penetrant systems (toluene/water) through multilayer structures is aa complex phenomenon. The permeability of toluene(method I) through this multilayer structure as compared to toluene/water vapor(method II) through the same multilayer structure proved to be 3-4 times greater magnitude under a particular 15 temperature, concentration, and relative humidity. The thermodynamics of the permeation of multi—component organic penetrants through polymer structures is not well understood at this time and will be the subject of future investigation Liu, Giacin, Hernandez (1987). (Hensley, Giacin, Hernandez (1991) undertook this investigation). Another important discovery was made. There is a threshold relative humidity value, above which toluene permeation proceeds at ea measurabbe rate, which signifies the permeation process as concentration dependent Liu, Giacin, Hernandez (1987.) Studies of organic penetrant/polymer systems have overwhelmingly been focused on single penetrant/polymer systems. However, tflma simultaneous permeation <1f binary mixtures is aa more accurate representation (Hf real life situations where the product aroma profile can contain a number of volatile components Hensley, Hernandez, Giacin (1991). The permeation experiments were conducted at 23°C at vapor activities between .21 and .5 using an isostatic technique described earlier by Hernandez (1984). This isostatic procedure was modified from Baner's quasi- isostatic procedure. The permeability of ethyl acetate and limonene, both individually and as ea binary mixture, were evaluated through. polypropylene. The permeabilities for 16 all experiments whether coincidental or not for binary mixtures were substantially higher than for single component tests, holding variables constant. At the lowest vapor activity, a 500% increase in the permeability of ethyl acetate vapor was reported as compared to the binary mixture: of ethyl acetate vapor and limonene. Units of an: -6 _§£JZ_) were used for permeability. *s*Pa n1 During the same time frame as Hensley, Takashi (1991) studied the permeation of ethyl acetate vapor through deposited polyethylene terephalate film and composite structures. This marks the onset of a series of students studying the aroma barrier properties for surface modified high barrier films. The Japanese market in 1988 made commercially available a silica deposited PP and PET film for retort pouches. This film has a number of desirable properties. It has a high barrier to 02 and water, is non-temperature sensitive, transparent, retortable, and Inicrowaveable. Takashi, Hernandez, Giacin (1991) Film samples of EVOH, MXD—6 (Nylon), and Silica deposited PET high barrier structures along with composite structure PET/PET/OPP, PET/SiOxPET/CPP and PET/EVOH/CPP retortable pouch structures were selected for this study. 17 A quasi-isostatic procedure was designed for this study as well. Probably based on Baner, Hernandez, Giacin g , were calculated m ‘*day*1 OOppm (1986). Permeance LHUIES of from time quasi-isostatic procedure. A table (n3 SI units g results was also presented as —7—————-. m *sec*Pa At 56% humidity, ambient temperature (22°C) and 190 ppm of ethyl acetate, both the ERKMI and silica deposited PET filHl showed rm) permeation. after 500 rxnuis of continuous testing. However, raising the humidity to 86% while keeping the other parameters constant adversely affected the EVOH, causing high transmission rate while still not showing any measurable permeation of ethyl acetate through the silica deposited PET Takashi, Hernandez, Giacin (1991). Retort temperature (120,125,130°C) and holding time (20,40,60 minutes) effect on the permeation rate was studied. As expected, an increase in temperature and holding time is synonymous with an increase in permeation. However, this increase is not linear and can be attributed to the point at which the SiOx layer is cracked resulting in macrovoids. Takashi has studied and reported these adverse cracking effects using EH1 optical microscope. It is therefore very' important to ‘understand. the impact of 18 macrovoids on the shelf life of a product. The presence of macrovoids (pinholes, cracking, poor seal immegrity, etc) has to 1x3 well understood enui under control. Otherwise, assuring' good. ibarrier‘ properties (microvoids) for ea particular product/package system.i¢3 considered.aa waste of time. Wangwiwatsilp, Hernandez, Giacin (1993) studied the mass transfer. parameters of toluene and ethyl acetate surface sulfonated PP, PET, and nylon. Baner's now classic quasi-isostatic methodology was utilized for these experiments, along with keeping in tact SI units for kgfin 2 O * * m sec Pa permeability Corona discharge, gas plasma, and flaming are all processes which improve the adhesion properties, along with fluorination, sulfonation, polymer blends, coextrusion and coating that can be used to impart increased hydrogen barrier properties when applied to polymers. A well- written and extensive review of surface modifications is covered by Wangwiwatsilp's (1993) literature review. The results of these studies have shown the effectiveness of the sulfonated layer in reducing the rates of transmission, enui the effective diffusion coefficient values of ethyl acetate and toluene through the sulfonated l9 PP filflh The surface sulfonated PET had little or no effect on the barrier properties of ethyl acetate, and the sulfonation process on nylon proved unsuccessful all together Wangwiwatsilp (1993). Future studies of time effects of ‘water‘ were deemed useful for this venture along with addressing food contact issues. An important point was also made to watch other industries for breakthroughs and possible applications for packaging/polymer industry; the electronics industry, in particular, ought to 1x3 watched. as ii: works extensively with deposition for microchips Wangwiwatsilp (1993). Lin, Harte, Giacin (1995) developed an isostatic procedure ti) measure taints enui off-flavors 1J1 foods and confectionery packaging. A good overview of threshold values for volatile compounds in foods and explanatory references for such information is included. Timely information on the threshold values for organic vapors in air and foods from the International Standards Organization (ISO) and the American Conference of Governmental Industrial Hygienist are additional sources of current information. (Georgia) Gu, Hernandez, Giacin (1997) studied the aroma barrier properties of ciay/polyimide nanocomposites. When nanocomposites are used as ea packaging material, the 20 composite enhanced strength and barrier properties make it possible to produce a package with a lower amount of material. Also, clay resources abound 1J1 natune and are cheap in cost. For a more thorough explanation of nanocomposites the reader is referred to this excellent literature review of the subject Gu, Hernandez, Giacin (1997). Two companies have recently developed commercially available permeation testing mechanisms for testing organic vapors through packaging materials. Both are isostatic procedures and are based on the assumption that the permeation process follows Ficks's first and second law as well as Henry's law; lModern Control's, MAS 2000 comes commercially equipped for testing under dry conditions only, with a temperature range from room - 200°C. Mocon provides the consumer with two available options, the Aromatran 1A and 2. Aromatran 1A can test a single permeant at dry conditions or a specific relative humidity with a temperature range from 5—65°C and is fully automated. The Aromatran 2 is a semi-automatic version and has a built in cryotrap for the increased sensitivity necessary fin: testing higher barrier materials. Recently, the MAS 2000 system was modified with a device for trapping the permeated organic aromas/volatiles. Ln this modified 21 configuration, the trapping system was designed to ensure that the sample cell chamber is continuously flushed with the carrier gas and the permeated vapor is conveyed to the trapping tube attached. The dynamic purge and trap/thermal desorption procedure showed EU) increase 1J1 sensitivity of three to four orders of magnitude over the continuous flow isostatic procedure Chang, Hernandez, Giacin (1996). Permeability measurements were compared to a non clay/polyamide coated polymer and a 2.5% clay/polyamide polymer. At 3.2 kPa and 23°C and 0% relative humidity the non clay/ polyamide structure showed a permeability of .12 * It f3,” compared with a permeability of 0.019 :3," for m *sec*Pa m *sec*Pa 2.5% (volume/volume)Clay/Polyamide, respectively. Organic concentration did NOT significantly affect permeability coefficient 'values for tima respective jpolyamide films (at 3.2 kPa anmi 1.7 kPa tested” .Also, test temperature does NOT markedly affect the permeation of ethyl acetate through clay loaded polyimide films over the temperature range studied Gu, Hernandez, Giacin (1997). A significant study was undertaken by Huang, Hernandez and Giacin to better understand the relationship and application of Baner's now classic quasi—isostatic IDrocedure to the new commercial MAS 2000 isostatic system. 22 Penetrants of ethyl acetate, toluene, limonene, methyl ethyl keone and a-pinene at 24°C were evaluated through glassine, HDPE, Oriented Polypropylene, Saran coated OPP, and Acrylic coated OPP. Values between the two testing methodologies were considered within acceptable limits. However, the limitation of 44 hr run with the MAS 2000 excluded some permeation. measurements for high. barriers. The following organic penetrant/polymer combinations had no measurable permeation after 44 hours of continuous testing with the MAS 2000: Ethyl acetate through Saran coated OPP and Acrylic coated OPP, toluene through Saran coated OPP and Acrylic coated OPP, limonene through oriented PP, Saran coated OPP, acrylic coated OPP, methyl ethyl ketone through Saran coated OPP, acrylic coated OPP and orpinene through HDPE, oriented PP Sarancoated OPP and acrylic coated OPP Huang, Hernandez, Giacin (1996). A mathematical consistency test for permeation measurements was developed by Hernandez and Gavara (1993). From the consistency analysis of the continuous flow permeability data, it (XNl be concluded that time diffusion processes were fickian and the parameters of the experiment were under control Huang, Hernandez, Giacin (1996). 23 Over the temperature range studied, the relationship between permeance and temperature follow well the Arrhenius expression Huang, Hernandez, Giacin (1996). Concentration levels greatly affected the permeance values but not the diffusion coefficients of flavor and aroma compounds in the barrier films Huang, Hernandez, Giacin (1996). The barrier properties of time six polymer structures evaluated, in order of decreasing barrier performance, are as follows: metallized PET/OPP, Acrylic coated OPP, Saran coated OPP, OPP, HDPE and Glassine. The MAS 2000 has a low limit of detectability ranging between 0.4 mg/hr for toluene permeability ti) 0.2 ma/hr fin: the permeability of ethyl acetate for continuous running 44 hours Huang, Hernandez, Giacin (1996). 24 Absolute Pressure Method There are two variations to the absolute pressure method: the manometric, high vacuum/time-lag technique, and volumetric, or constant volume/variable pressure, and constant pressure/variable volume. The first is the classical method defined by Barrer and Skirrow 1948. The general equations and setup of Barrer's manometric technique are as follows. The whole diffusion cell is first thoroughly degassed at a fairly high temperature and the thermostat adjusted to the required temperature. By means of the Toepler pump (T), gas is introduced to the unsupported side of the membrane, the pressure being indicated. by the barometer (B). Throughout the experiment the pressure is kept constant by manipulation (HE the Toepler pump. 'Lhe gas is permeated through time membrane into ea vacuuml chamber of known volume and the increase in pressure with tie is followed by a McLeod gage, and a pressure vs. time plot is made. The experiment is continued until the slope becomes constant when the steady state of flOW' has been established. From the steady state the permeability constant P may be calculated Barrer (1948): 25 P=273.r._l__._1_ T pl a 76 The majority of mass transport testing initially was done with inorganic gases, rubbers, or ethylene. The famous "Dow cell" was also based on Barrer's method and was successfully used ti) test 02 and water permeabilities for many years (ASTM D1434). The cell however was not capable of measuring organic vapors without modifications. Barrer's classical technique vmus modified ti) enable it ti) measure organic substances as vmflii The absolute pressure method is limited also because it does not determine the permeability of gases at different relative humidities. Since an absolute pressure differential across the membrane is used, it is plagued with leakage problems, and cannot be used with pressure sensitive or easily deformable films Talwar (1974). A more fundamental problem with the method also exists because the detection system cannot differentiate between co-permeating vapors. The method is therefore restricted to measuring the permeation of pure vapor only. The effects of co-permeants, in particular, water vapor, cannot be evaluated Baner (1987). 26 Gravimetric Method Variations of the gravimetric technique have been utilized kn! many researchers ti) study time mass transport characteristics (Hf organic vapors through various polymer structures. The nature of the gravimetric procedure makes it necessary to thoroughly understand the polymer/permeant mass transport characteristics before selecting this method for determining the permeability of organic compounds through.ea polymer. fflme gravimetric procedure, unlike the absolute pmessure mathod sum) quasi-isostatic/isostatic methods, indirectly determines the permeability coefficient. This makes it necessary for the mass transport system to follow fickian behavior, thus enabling P = D * S, where P = the permeability coefficient, D = the diffusion coefficient, and £3== the solubility coefficient. (An explanation of fickian behavior is out of the scope of this project and the reader is referred to Hernandez (1986) for a thorough explanation of this subject.) Until now the only way to determine if the polymer/penetrant combination has followed fickian type behavior was to compare the results of Crank's (1975) sorption. equation vniit calculated. results. However, the development of a database for mass transfer, the main objective of this research, provides an additional tool to 27 determine if time polymer/penetrant combination ii; fickian in behavior. Currently, the preferred apparatus for conducting sorption experiments is an electrobalance because this system continually records the weight gain or loss of the sample as a function of time. In addition, this system is often interfaced INith ea vapor~ generator system, allowing sorption measurements to be conducted over a range of penetrant vapor concentration levels (Barr 1997). General state of the art gravimetric electrobalance technique is described as follows by Barr 1997: Using the gravimetric electrobalance technique, the solubility coefficient value can be obtained by first suspending a film sample weighing approximately 30mg in the electrobalance hangdown tube, where it surrounds the polymer sample. The weight change of the sample is continuously recorded as a function of time, using either a trip chart recorder or compuber. Once steady state level of sorption has been obtained, the solubility coefficient value can be determined from the following expression: M... w°b Where 53 is the solubility coefficient value, expressed as mass of vapor sorbed at equilibrium per mass of polymer per driving force. Alw represents the total mass of vapor sorbed by the polymer at equilibrium at a given temperature, w is the initial weight of the polymer test sample, and b is the value of the permeant driving force. Experimental sorption data is usually’ presented graphically as a plot of AL/Alw as a function of the square root of time, with the initial portion of the curve being linear (Meares, 1965). The diffusion equation appropriate for the sorption of penetrant by a polymer sample in film or sheet form was described by Crank (1975) as: M: 8[ —D-fl’2-[ -9D-7r2-£ Moo 1 7n exp( [2 )+%exp( €2 )] S: 28 Where A4, and 4L3 are the amount of penetrant sorbed by the polymer film sample at tinmet: and the equilibrium sorption after infinite time, respectively; t.:h3 the time required to reach A4,, amd i represents the film thickness. If the experimental and calculated curves are ii) good agreement, the diffusion process is usually considered Fickian, and an accurate estimation of I) can tme made (Nielson anmi Giacin 1994). This is achieved by setting Nfl/Adw = 0.5 and calculating the sorption diffusion coefficient as follows: 0.04%2 .Ds=-————— ’05 Where: DS is sorption diffusion coefficient, and (05 is the time required to attain half of the sorption level at steady state. Once the solubility and diffusion coefficient values have been determined, the permeability coefficient value, I’, can be obtained from Equation }’=l)xS Where P is the permeability coefficient value, and D is the diffusion coefficient value, and S represents the solubility coefficient value. If the reader is interested in solubility coefficients, Fayoux (1996) who has done an extensive literature review (H) the subject if; recommended. Another good explanation of the applicability of the gravimetric procedure is given by Mohney, Hernandez, and al. (1988). 29 Database Overview A database can be defined as an extensive list of information systematically categorized. for easy and fast sorting. In today's fast paced, information intensive society, databases are the engines which drive many of these new software platforms. One prominent example is the Yahoo search engine, which is backed by a database. Microsoft Access 97 was utilized to program the Permeability of Organic Compounds Through Various Packaging Polymers Database. Unlike traditional programming methods, Microsoft Access 97 uses object-oriented programming. For this reason, it is not possible to print out a list of code for the entire programu The use of Access 97 can be understood and applied at various levels. The capabilities of Microsoft Access 517 are further extended by time use of macros, visual basic for applications programming (VBA), and standard query language (SQL). A working knowledge of the following topics is necessary in order to understand the mechanics of the database developed for this thesis. 1) Forms 2) Tables 3) Modules 4) Macros 3O 5) Visual Basic for Applications 6) Standard Query Language 7) Security It should tie taken into consideration that a successful database «design relies greatly (N1 the initial planning period where the problem must be clearly defined. 31 Three Database Form Types Used Forms are the visual storefront of the database. A well—designed form should be both functional and visually appealing. In order to execute functions, forms are linked with tables and sometimes queries. There are three basic form types used in this thesis. The main input form Figure 1, pop-up forms (used for both calculations and addition of new information), and the main and advanced query form. Figure l. 1) Main Input Form, 2) Query Form and 3) Pop—Up Addition and Calculation Form. 32 Database Forms When designing a new form there are two basic options: Manual "design View" or various automated "form wizards". Figure 2. The database developed for this thesis was completely fabricated in "design View" due to the specific needs of this database. After selecting "design View", the user arrives at the screen in Figure 3. As can be seen, there are many options to both configure and design a new or existing form. Figure 4 depicts a possible form in design view. Figure 2. New Form, "design view" and "wizards" 33 Figure 4. 35'; .3: 1.. {’r . 'Design View" modification 34 Database Toolbox The toolbox in Figure 5 is at the heart of "object oriented programming". The appropriate tool must be selected from the toolbox and placed on the form. The selected tiifl. can then tie manipulated kn! either following the pre made immiiuctions, designing ea separate macro, or writing' some ‘visual basic fin: applications code. While designing the database, the tab control tool was utilized to navigate between each of the major parts of the database. Rectangles, lines, labels and text boxes were all employed numerously to define forms. Combo boxes were also implemented in time database design. to select items from more than one drop down list. Option buttons were programmed utilizing visual basic for applications to select the appropriate partial pressure gradient unit. Command buttons were frequently actuated to accomplish everything from a complex permeability calculation, to closing a form, to turning on and off the visibility property of various cells, both using visual basic for applications and macro programming. 35 Label Text Box Toggle Button Option Group Combo Box Check Box List Box Option Button Line Command Button Image Bound Object Frame Page Break Subform/Subreport Rectangle More Controls Unbound Tab Control Object frame Figure 5. Toolbox 36 Database Tables A database table can be imagined as lists of information separated into appropriate categories. Interestingly enough, time database table ii; never seen tn! the user of a well-designed database, but is affixed to a more elegantly designed form. The planning stage requires the database constructor to define clearly the "fields", or categories, which time data should kme divided into. These fields will determine how information (in) be entered into the database, later sorted and retrieved via a query. In order to speed up the query of the database and to minimize errors, numerical identification fields are assigned to each of the text—based fields. This practice becomes increasingly important as the database acquires more information. How does the design of a table work? As with a new formt design, the table "wizard" functions have rmfl: been used in the design of this database. Tables can be both imported from other databases and linked. The permeability database designed for this database uses the linking feature. There VMHKL therefore, tin) databases developed. One with all tables, and the other with the rest of the information. This system allows different database fronts 37 to be used later, and offers the optimum framework for expansion. Figure 6. New Table The two different table types created in this database include the main table and individual function, or calculation tables. The main table is the place where all the "quereable information" is stored after conversion in the main input page. Permeability, solubility, diffusion coefficients had to be converted into Standard International Units in order to be available for later purposes. This was one of the biggest challenges faced designing this database. The second types of tables used were created for use as conversion calculators for the mass transfer calculations. 38 Figure 7 is the screen which arrives after selecting design View. For the design of this database only text and number data types were used. As can be seen from Figure 7, there are many other ways and possible applications for table functions and design. Table design View Figure 7. 39 Database Queries Queries are used to sort data from a table or another query according to the question raised. The query can ask information from multiple tables and combine the results into one. Queries are also non—visible to the user and are attached ti) a. more user accessible form. 1m; with the design of new forms and tables, the "design View" was used for new query design as seen in Figure 8. The query proves why the preliminary design of the database is so important. The database programmer can only sort the data by the "fields" or categories developed. In the query process, the linking of various pertinent tables and/or queries can be created to enable the programmer to sort data according ti) the needs (Hf the user. Figure 10 shows a new query in "design View". The query designer has the chance ti) mine information from ea table, query, or both. An example of a category or "field" which was added into this database to expand the searching capabilities is the penetrant/permeant compound class. This addition enables the user to search not only a specific compound but also a complete compound class. If this had not have been included during the initial design process, adding it later would tme comparable ti) redesigning ea car~ chassis ifl the 40 late stages of its manufacturing. Not only' would it be necessary to update each record, but the tables, forms and queries would all have to be modified. . Slrple Query Wizard ._ Crosstab Query Wizard Figure 8. New Query Figure 9. New Query Design View 41 Standard Query Language (SQL) can be applied to assist the user for more complex sorting requirements. Figure 10 depicts the SQL "query View". The use SQL programming was needed to enable the user to start the query with either a polymer or a permeant/penetrant. J Hum [Ann-v. V ,» 1 Uurewl fir-Jed Uuelv } SELECT: Figure 10. SQL Query view 42 Database Macros, Visual Basic for Applications, and Modules A database macro is programmed to perform a specific function. fflme use of macros is cnme of the features which is possible with object oriented programming. While macros are not as complicated to program as Visual Basic for Applications, they are slower. Both macros and Visual Basic for Applications were used to drive the functions of this database. When designing a new macro, the first step is to choose which action will be performed. This having been determined, the expression builder is used to combine various cell values into a calculation as shown in Figure 11. The solubility, diffusion and activation energy were calculated in this manner. It is interesting to note that the permeability constant could not be calculated with a macro. This particular calculation exceeded the limits of the macro. In this case a module was designed using VBA code as viewed in Figure 12. However, a macro was still used to run the module. It would be possible to program the code directly into the calculation button. for permeability, solubility, diffusion, activation energy, etc. kn; using either macros or Visual Basic for Immflications code. One advantage of programming in this manner is that it offers the ability to 43 use these macros and modules for other applications or calculations within the database. Another advantage is that it provides an improved organization of the calculations. This becomes increasingly important as the complexity of the database evolves. -n rtcan’zr: {53:3 5mmwmmmmmmmmgfiffiflammm 1: es].Egan]![auWZflFm]![Form]l[V&m].[Fom]l[u m Figure 11. Macro builder 44 4 Q; ‘G Option Compare Database d g? Option Explicit Function calcl () .1 Dim E L: Control, IBU As Control, EC 1: Control, THC 1: Control, .lC A: Control '9 Dim TIC A: Control, PRC As Control, PD L9 Control, RES 1: Control 'Ln'n'u A:,-.1< . A < 1 Set E = Forms![Form] ![Velues] .Forn! [entry] Ill! - Form! [Form] ![Values] .Form! [Input Holeculer weight] C :1] Set THC = Form! [Form] ![Velue:] .Form![th1ckcoett] Set 1C = Form! [Form] ‘ [Values] .l'orm![ereacoe11] Set TIC - Form ’ [Form] ![Values] .Form![timeCoe1£] Set PRC - Fom'florm] ![Velues] .Form' [ppdcoett] Set PD - Form' [Form] '[Velues] .Form' [Input polymer density] Set R15 - Forma'[Form] '[Velues] .Form'[Permeeb111ty SI] Rls- (E'IHU'HC’THC) / (AC‘Z‘TIC'PRC'PD) End Funct ion .52.? KC - Fom![Form] '[Velues] .Form! [Hus oe _ i F Figure 12. Permeability Calculation Module 45 Database Security Database security is a very important issue. Microsoft Access 97 provides a secure application with many levels of permission possible. Figure 13 pictures the Login menu before entering into a secured database. There is always one administrator with the possibility to add and delete an unlimited number of users and user groups with varying levels of permissions. If the password is lost there is NO possibility for retrieving the database. This is why the wrkgadm information must be kept in a safe place Figure 14. Figure 13. Security Login Figure 14. MS Access Workgroup Admin. 46 Database Layout Database #1 Database #2 . Tables Only : . Forms, Queries, Reports, Macros, Modules Text Field Complete Main Basic _>Basic - Combo BOX Record Input Query «Query ' Pop-up Set ; Calculations . Limits Data . User Form Menu 1 1 Conversions . Relationship Query llser lnterfiace Friendly l .;. Additions ‘ Advanced Advanced —> Query <—Query Figure 15. Schematic of Database Mechanics #1 47 a.“ :v-u. , _ mu ._. 9 x i I usnvinue Figure 16. Schematic of Database #2 48 Overview Input Reference One page input was developed to improve the reliability of inputting all information from a given reference. This input page is meant to be used only by administration and (in) be limited kn! security options to users. Multiple pop up menus and extensive programming and planning have been used to make this page as straight forward and error free as possible. The page (mu) be divided into tin) distinct areas: the literature reference section and the permeant/penetrant, mass transfer calculation section. Since there enie more calculations than literature references the calculation section was designed as a subform of the literature reference. This makes it possible for more than one entry per literature reference. It also efliminates needing to enter the literature reference each time new polymer/penetrant combinations aume entered into time page. Visual Basic for Applications programming has been used to improve the speed and accuracy of the permeability, solubility, diffusion, activation energy' and. partial pressure gradient conversion calculations. It makes them more straightforward. Because the selection of the desired calculation is possible, only the appropriate fields to be 49 filled in are left "active", greatly reducing errors and speeding up the tedious input process. _r..: % .uutllur ‘ intuit-«r Po I5. nu; v Pu m. m ' Juno Cl1 Figure 17. 1 page Input Reference 50 Literature Reference The literature reference as shown :Ui Figure 18 is a section of the 1. page input reference page. Its leaves complete flexibility with additional buttons available to add any new type of entry desired. The user, a database administrator, may therefore enter new magazine articles, book titles, or even custom internal data from the user‘s own laboratory. Hum Input ‘ P uhhaher E'JUOI Reference l; Ewaaan HEI’FEIl-flfl§fififi§§ Figure 18. Literature Reference Section of the Reference Input 51 Input Reference Mass Transfer Mass Transfer is a function of the partial pressure gradient. The user is expected to enter the polymer, permeant/penetrant desired, organic compound class, mass transfer test method, and any additional information in the polymer description field as can be seen in Figure 21. The user then selects one of the mass transfer functions along with one partial pressure gradient function as seen in Table 1. The software: has been. designed ti) leave only "active" the mass transfer‘ or partial pressure gradient fields necessary to fill.:Ui for each calculation desired. Standard International Units (SI) are calculated for each function. Both the "active" fields and SI conversions were accomplished using Visual Basic for Applications programming. Table 1. Input reference mass transfer Mass Transfer Partial Pressure Gradient Permeability ppm mass/vol Solubility ppm vol(STP)/vol Diffusion ppm vol(liquid)/vol Activation Engergy mol/L Vapor Activity Pressure Units 52 ppm when WI 4):,- Pa um: Figure 19. Mass Transfer Input Reference 53 Mass Transfer Calculations Figure 20 isolates the mass transfer calculation section of the input reference section of the database. Figure 20. Mass Transfer Section of the input reference Visual Basic for Applications programming was used to manipulate Microsoft Access 97. Figures 21, 22 and 23 depict how the calculations of permeability, solubility and diffusion are setup. Table 2 lists the Visual Basic for Applications code used to calculate each of the mass transfer functions. The code was written using case statements. As an example, case 1 was written as the permeability calculation. Table 3 lists the Visual Basic for Applications code used to "activate", "freeze", hide and show each of the functions seen in Figures 21, 22 and 23. 54 Table 2. VBA mass transfer calculation code Private Sub Button_masstranscalc_Click() Select Case Frame_MassTransfer.value Case 1 [Permeability SI].value = entry.value ((MassCoeff.value * PermMW.value * thickcoeff.value) (areacoeff.value ‘* timeCoeff.value ‘* ppdcoeff.value PolyDensity.value)) 3 Case 2 [Solubility SI].value = entry.value ((MassCoeff.value * PermMW.value * PermDensity.value) (massZcoeff.value * PolyDensity.value * ppdcoeff.value)) Case 3 [Diffusion SI].value = entry.value (areacoeff.value / timeCoeff.value) Case 4 [Forms]![Form]![Values].[Form]![Frame_Activation].SetFocus Case Else Dim strMsg As String, strInput As String ' Initialize string. strMsg = "Please select a calculation type before" End Select End Sub 55 Table 3. VBA written for switching active cells on/off Private Sub Frame_MassTransfer_AfterUpdate() Select Case Frame_MassTransfer.value Case 1 [Permeability SI].Enabled = True Toggle_Permeability.Enabled = True [Solubility SI].Enabled = False Toggle_Solubility.Enabled = True [Diffusion SI].Enabled = False Toggle_Diffusion.Enabled = True Toggle_Activation.Enabled = True Activation_PSI.Enabled = False Activation_DSI.Enabled = False Activation_SSI.Enabled = False Button_Mass.Enabled = True Mass.Enabled = True MassCoeff.Enabled = True Button_Thick.Enabled = True thick.Enabled True thickcoeff.Enabled = True Button_Area.Enabled True Area.Enabled = True areacoeff.Enabled = True 56 Button_Time.Enabled = True Time.Enabled = True timeCoeff.Enabled = True Button_Pressure.Enabled = True PPD.Enabled True ppdcoeff.Enabled = True Button_Energy.Enabled = False energy.Enabled = False EnergyCoeff.Enabled = False Button_MassPol.Enabled = False mass2.Enabled = False mass2coeff.Enabled = False Option_P.Enabled False Option_D.Enabled False Option_S.Enabled False Button_masstranscalc.Enabled = True OLE_Perm.Enabled = True OLE_Sol.Enabled = False OLE_Diff.Enabled = False OLE_Act.Enabled = False [Forms]![Form]![Values].[Form]![entry].SetFocus Case 2 [Permeability SI].Enabled = False Toggle_Permeability.Enabled = True 57 [Solubility SI].Enabled = True Toggle_Solubility.Enabled True [Diffusion SI].Enabled = False Toggle_Diffusion.Enabled = True Toggle_Activation.Enabled = True Activation_PSI.Enabled = False Activation_DSI.Enabled = False Activation_SSI.Enabled = False Button_Mass.Enabled = True Mass.Enabled = True MassCoeff.Enabled = True Button_Thick.Enabled = False thick.Enabled = False thickcoeff.Enabled = False Button_Area.Enabled = False Area.Enabled = False areacoeff.Enabled = False Button_Time.Enabled = False Time.Enabled = False timeCoeff.Enabled = False Button_Pressure.Enabled = True PPD.Enabled = True ppdcoeff.Enabled = True Button_Energy.Enabled = False 58 energy.Enabled = False EnergyCoeff.Enabled = False Button_MassPol.Enabled = True mass2.Enabled = True mass2coeff.Enabled = True Option_P.Enabled = False Option_D.Enabled = False Option_S.Enabled = False Button_masstranscalc.Enabled = True OLE_Perm.Enabled = False OLE_Sol.Enabled = True OLE_Diff.Enabled False OLE_Act.Enabled = False [Forms]![Form]![Values].[Form]![entry].SetFocus Case 3 [Permeability SI].Enabled = False Toggle_Permeability.Enabled = True [Solubility SI].Enabled = False Toggle_Solubility.Enabled = True [Diffusion SI].Enabled = True Toggle_Diffusion.Enabled = True Toggle_Activation.Enabled = True Activation_PSI.Enabled False Activation_DSI.Enabled False 59 Activation_SSI.Enabled = False Button_Mass.Enabled = False Mass.Enabled = False MassCoeff.Enabled = False Button_Thick.Enabled = False thick.Enabled = False thickcoeff.Enabled = False Button_Area.Enabled = True Area.Enabled = True areacoeff.Enabled = True Button_Time.Enabled = True Time.Enabled = True timeCoeff.Enabled = True Button_Pressure.Enabled = False PPD.Enabled = False ppdcoeff.Enabled = False Button_Energy.Enabled = False energy.Enabled = False EnergyCoeff.Enabled = False Button_MassPol.Enabled = False mass2.Enabled = False mass2coeff.Enabled = False Option_P.Enabled = False Option_D.Enabled = False 6O Option_S.Enabled = False Button_masstranscalc.Enabled = True OLE_Perm.Enabled = False OLE_Sol.Enab1ed = False OLE_Diff.Enabled = True OLE_Act.Enabled = False [Forms]![Form]![Values].[Form]![entry].SetFocus Case 4 [Permeability SI].Enabled = False Toggle_Permeability.Enabled = True [Solubility SI].Enabled = False Toggle_Solubility.Enabled = True [Diffusion SI].Enabled = False Toggle_Diffusion.Enabled = True Toggle_Activation.Enabled = True Activation_PSI.Enabled = True Activation_DSI.Enabled = True Activation_SSI.Enabled True Button_Mass.Enabled = False Mass.Enabled = False MassCoeff.Enabled = False Button_Thick.Enabled = False thick.Enabled = False thickcoeff.Enabled = False 61 Button_Area.Enabled = False Area.Enabled = False areacoeff.Enabled = False Button_Time.Enabled = False Time.Enabled = False False timeCoeff.Enabled Button_Pressure.Enabled = False PPD.Enabled = False ppdcoeff.Enabled = False Button_Energy.Enabled = True energy.Enabled = True EnergyCoeff.Enabled = True Button_MassPol.Enabled True massZ.Enabled = True mass2coeff.Enabled = True Option_P.Enabled = True Option_D.Enabled = True Option_S.Enabled = True Button_masstranscalc.Enabled = False OLE_Perm.Enabled = False OLE_Sol.Enab1ed = False OLE_Diff.Enabled = False OLE_Act.Enabled = True [Forms]![Form]![Values].[Form]![entry].SetFocus 62 Case 5 Frame_MassTransfer = Null Frame_Activation = Null PolyMW.value = l PermMW.value = l PolyDensity.value - 1 H H PermDensity.value MsgBox "Please select Permeability, Diffusion, Solubility or Activation button" [Forms]![Form]![Values].[Form]![Frame_MassTransfer].SetFocu 3 End Select Forms!Form!Values.Form!PermMW.Visible = False Forms!Form!Values.Form!Label_PermeantMW.Visible = False Forms!Form!Values.Form!PermDensity.Visible = False Forms!Form!Values.Form!Label_PermeantDensity.Visible False Forms!Form!Values.Form!PolyDensity.Visible = False Forms!Form!Values.Form!Label_PolymerDensity.Visible False End Sub 63 :1 HI :kness '3: CL'lIU" @mfla lidrhons Figure 21. Permeability Calculation 64 ddfllnns Figure 22. Solubility Calculation 65 Figure 23. Diffusion Calculation 66 It is important to understand that these three calculations for Permeability, Solubility, and. Diffusion have been reported in many measurements; and, therefore, up until now, have been utterly impossible to effectively compare. While many articles taken from the 1950's to today have been reviewed to come up with the maximum of different possibilities for all variables in each equation, there may be new ones, or some which are missing. Additionally, new measurement techniques are being designed and implemented each. day; It is for’ this reason. that the database ‘was programmed with flexibility in mind, enabling the user to add new calculations or units to the table. However, the final objective has always been to normalize the data into standard international units. FUrthermore, every effort was made to automate the tedious process of data entry’ by programming a user-friendly interface whereby human data entry errors should be minimalized. 67 Input Reference Partial Pressure Gradient The partial pressure gradient was designed using a substantial amount of visual basic for applications programming to keep the user from making errors and to speed up the calculation process. Table 4 lists the code used to "activate", "freeze", hide and show each of the functions seen in Figures 25—30. Table 5 is the partial pressure gradient calculation code. - . _. - Partial Pressure Gradient ppm MILLS. vol w u wi3illllllll 31“”k ”‘33 llllllflm”m“ i mvo S e“!- ' m _m p... 0qude t... — l termed-«WW _ mIJIZ.’I L ‘u’opor Acimty _ pressure units. _ _ I '- 35W ‘ 2.223 -F"J’_-‘|Lo|;‘ _ f"; H urnidiry Figure 24. Partial Pressure Gradient Table 4. VBA Partial Pressure Gradient code Private Sub Frame_Gradient_AfterUpdate() Select Case Frame_Gradient.value Case 1 ppm2.Enabled = True ppml.Enabled = False ppm3.Enabled = False molsvol.Enabled = False 68 VAl.Enabled False VPl.Enabled False [button_A_Saturation_VP].Enabled = True Moll.Enabled = True [button_MWpermeant].Enabled = True [button_additionMWpermeant].Enabled = True TempCSI.Enabled = True [button_tempconvert].Enabled = True Pden1.Enabled False [button_permeantdensity].Enabled = False [button_additionpermeantdensity].Enabled False SVPl.Enabled = False [buttonmSVPconversion].Enabled = False [Calc_PPG].Enabled = True [Forms]![Form]![Values].[Form]![ppm2].SetFocus Case 2 False ppm2.Enabled True ppml.Enabled ppm3.Enabled False molsvol.Enabled = False VAl.Enabled False VPl.Enabled False [button_A_Saturation_VP].Enabled = False Moll.Enabled = False 69 [button_MWpermeant].Enabled = False [button_additionMWpermeant].Enabled = False TempCSI.Enabled = True [button_tempconvert].Enabled = True Pdenl.Enabled = False [button_permeantdensity].Enabled = False [button_additionpermeantdensity].Enabled = False SVPl.Enabled = False [button_SVPconversion].Enabled = False [Calc_PPG].Enabled = True [Forms]![Form]![Values].[Form]![ppml].SetFocus Case 3 ppm2.Enabled = False ppml.Enabled = False ppm3.Enabled = False molsvol.Enabled = True VAl.Enabled False VPl.Enabled False [button_A_Saturation_VP].Enabled = False Moll.Enabled = False [button_MWpermeant].Enabled = False [button_additionMWpermeant].Enabled = False TempCSI.Enabled = True [button_tempconvert].Enabled = True 70 Pdenl.Enabled = False [button_permeantdensity].Enabled = False [button_additionpermeantdensity].Enabled False SVPl.Enabled = False [button_SVPconversion].Enabled = False [Calc_PPG].Enabled = True [Forms]![Form]![Values].[Form]![molsvol].SetFocus Case 4 ppm2.Enabled False ppml.Enabled False False ppm3.Enabled molsvol.Enabled = False VAl.Enabled True VPl.Enabled False [button_A_Saturation_VP].Enabled True Moll.Enabled = False [button_MWpermeant].Enabled False [button_MWpermeant].Enabled False True TempCSI.Enabled True ll [button_tempconvert].Enabled Pdenl.Enabled = False [button_permeantdensity].Enabled = False [button_additionpermeantdensity].Enabled = False SVPl.Enabled = True 71 [button_SVPconversion].Enabled = True [Calc_PPG].Enabled = True [Forms]![Form]![Values].[Form]![VA1].SetFocus Case 5 ppm2.Enabled = False ppml.Enabled = False ppm3.Enabled = False molsvol.Enabled = False VAl.Enabled = False VPl.Enabled = True [button_A_Saturation_VP].Enabled = False Moll.Enabled = False [button_MWpermeant].Enabled = False [button_additionMWpermeant].Enabled = False TempCSI.Enabled = True [button_tempconvert].Enabled = True Pdenl.Enabled = False [button_permeantdensity].Enabled = False [button_additionpermeantdensity].Enabled = False SVPl.Enabled = False [button_SVPconversion].Enabled = False [Calc_PPG].Enabled = True [Forms]![Form]![Values].[Form]![VPl].SetFocus Case 6 72 ppm2.Enabled = False ppml.Enabled = False ppm3.Enabled = True molsvol.Enabled = False VAl.Enabled = False VPl.Enabled = False [button_A*Saturation_VP].Enabled = False Moll.Enabled True [button_MWpermeant].Enabled = True [button_additionMWpermeant].Enabled = True TempCSI.Enabled = True [button_tempconvert].Enabled = True Pdenl.Enabled = True [button_permeantdensity].Enabled = True [button_additionpermeantdensity].Enabled = True SVPl.Enabled = False [button_SVPconversion].Enabled = False [Calc_PPG].Enabled = True [Forms]l[Form]![Values].[Form]![ppm3].SetFocus Case 7 Frame_Gradient = Null ppm2.value = Null ppm1.value = Null ppm3.value = Null 73 molsvol.value = Null VA1.value Null VP1.value Null Moll.value = Null TempCSI.value = Null Pden1.value = Null SVPl.value = Null [%_Humidity].value = Null ConAnswer1.value = Null ConVP.value = Null End Select End Sub 74 ppm m .0! ppm with“ STL‘i‘ ppm '-,>'I)i“l-Jl.lld ‘ f-‘JI‘E units Figure 25. Partial Pressure Gradient , L. . . . - ddltmns Partial Pressure Gradient: 75 ppm mass/vol ppm m Partia| Pressure Gradient ppm "“lJil'STp ppm '40l[hutndl.~"'--'c-l moin‘ l. ’n’eror Art n- I13; Drezurc units- Figure 26. Partial Pressure Gradient: vol(STP)/vol 76 ppii' Vapor 4.);‘ii'.'tl'\-‘ '1'»; Mint: .unvn-m-I m In. It"! rm .L. ‘3 . Truman, ., Figure 27. Partial Pressure Gradient: ppm vol(liquid)/vol 77 ppmm ‘ Par ial Pressure Gradient ppm VIJIIET ppm mil hqwd lx'vc-l moisn'L Honor Activity Pressure units Temperature? Figure 28. Partial Pressure Gradient: mol/L 78 ppmm rm 2 Partial Pressure Gradient grams/moi ppm \."l:i|i:STp‘JA"‘="ji _ _ ,, ' - 4 . . .. _l~€ ' w" ppm 'vsollhquidls‘vol mo l:.~' L Figure 29. Partial Pressure Gradient: Vapor Activity 79 . pp,“l.w_.i,v.c,, ; _ ‘ . Partial Pressure Gradient ‘ ._ grams-"mini . ppm~.-'nli_STF'I.-‘--.Inl 2 ’ . ppm rollliq1_i|di.-"vol " . I'm] l_‘." L . ‘u‘apor Adi-«m, 9 Drescurt unit: Figure 30. Partial Pressure Gradient: Pressure Units Table 5. Partial Pressure Gradient Calculation Code Private Sub Calc_PPG_Click() Select Case Frame_Gradient.value Case 1 ConAnswer1.value = ppm2.value * 0.000001 * 82.06 * 101325 * TempCSI.value / (Moll.value) Case 2 80 ConAnswerl.value = ppm1.value * 0.000001 TempCSI.value * 82.06 * 101325 / 22414 Case 3 ConAnswerl.value == molsvol.value ‘* 0.08206 TempCSI.value * 101325 Case 4 ConAnswerl.value = VAl.value * SVPl.value Case 5 DoCmd.RunMacro "Open.VPl" Case 6 ConAnswerl.value = ppm3.value * 0.000001 TempCSI.value * 82.06 * 101325 * Pden1.value / Moll.value Case Else Dim strMsg As String, strInput As String ' Initialize string. strMsg = "Please select a calculation type before" End Select End Sub 81 Standard and Advanced Query Polymer or Permeant may be selected to query first as shown in Figures 33 and 34. The advanced query form is available to see at Figure 35. The query and some of its table ties, and the "SQL design View" can be checked out in Figures 36 and 37. Figure 32 is the standard query form before selection of polymer or permeant. Table 6 is the standard query form ‘visibility, requery and reset Visual Basic for Applications code. was —:'i.§1’é mm m m Figure 31. Standard Query Form 82 Figure 32. Standard Query Form "Design View" 83 g; a: pi" e e“ 5 L lll Figure 33. Standard Query Form: Which Polymer? 84 a a m . a _ .mm mm a a m ? : Which Permeant Standard Query Form Figure 34. 85 Figure 35. Advanced Query Form Table 6. Standard Query Form: visibility, requery and reset code Private Sub DirectionToggle_AfterUpdate() Polymercombo.Requery OCCCombo.Requery SOCcombo.Requery If DirectionToggle Then 'selected Frame60.Visible = True PenetrantText.Visible = True 86 I’uw SOCcombo.Requery OCCCombo.Requery SOCcombo = Null OCCCombo = Null SOCcombo.Visible = (Frame60.value = l) OCCCombo.Visible = (Frame60.value = 2) Polymercombo.Visible = False Else Frame60.Visible = False PenetrantText.Visible = False SOCcombo.Visible = False OCCCombo.Visible = False Polymercombo = Null Polymercombo.Requery Polymercombo.Visible = True Plastics_Label.Visible = True End If Label_PolyPen.Visible = False End Sub 87 Wyn.” arr- -. _. Figure 36. Standard Query "Design View" 88 _ A__Ln__.__n_-_-A .11—4 -1 ‘A an; “Jmm!m.. a. -._.A La aria tag new Insat Quay luua Warm neg: -- W W. A1133 15' g 5;: 1?; c > a a an! 9 >43 .;.. -:-.\ be» a; . SELECT TABLEAutonuInber. Value. ConAnswerl. Value. Penneabilily_ SI. Value. Humidity. TABLE. Year. Value. TempCSl. fl DataOuaLID. DalaOualin. Value. Diflusion_SI. Value. Solubility_Sl. ValueAcliwtion_PSl. ValueAdWation_DSl. ~ Value.Activation_SSl. TABLE.Vqume. TABLE.Page. TABLE.NuInber. Soc_lD.[Specific Organic Cmpdsl. Pol_lD.Plasflcs. Occ_lD.[0rganic cmpd classes]. IfltlsNuII[[McthodD_lD].[MethodD_lDI].0.[MethodD_ID].[MethodD_lD]] AS D. MethodD_lD.MelhodD. Ilt[lsNull[[MethodP_lD].[MethodP_|D]].0.[MethodP_ID].[MethodP_ID|] AS P. MethodP_lD.MetlIodP. IIIlIsNuIIflMetIIodS_lD|.[MetIIodS_ID|].0.[MethodS_lD].[MethodS_lD]) AS 8. MethodSJDMethodS, TABLE.TII_ID. Tit_ID.TItIe. TABLE.ReI_ID. ReI_|D.Rclerence. TABLE.PuII_ID. Pub_ID.Pub|Ishcrs. Value.|lnput Molecular weight]. Occ lD.0cc ID FROM Tit_ID RIGHT JOIN [[Rel_lD RIGHT JOIN [Pub_lD RIGHT JOIN flTABLE] LEFT JOIN DataOual_lD ON TABLE.Data0uaI_ID = DataOual_lD.Dala0ual_lD] ON Pub_lD.Pub_lD = TABLE.PuII_ID] ON ReI_|D.Rcl_lD = TABLE.Ref_ID] LEFT JOIN [Soc_lD RIGHT JOIN [PoI_ID RIGHT JOIN [0cc_lD RIGHT JOIN [MethodSJD RIGHT JOIN [MethodP_lD RIGHT JOIN [MethodD_lD RIGHT JOIN [Value] 0N MethodD_ID.MethodD_lD = Value.MeIhodD_lD] ON MethodP_lD.MethodP_ID = Value.MethodP_lD] 0N MethodS_lD.MethodS_lD = Value.MethodS_lD| 0N Occ_ID.Occ_ID = alue.0cc_lD] 0N Pol_lD.Pol_ID = Value.Po|_lD] ON Soc_lD.Soc_lD = Value.Soc_lD] 0N TABLEAutonumber = alue.Autonumberj ON Tit_lD.Tit_lD = TABLE.Tit_lD ERE [[lOcc_ID.Occ_ID] Like IlfllsNuIlflFormsll|0_PoIlSodIlOCCcombolL'”.[ForrnslI[O_PolISoc|I|0CCcombo]]| AND [[IlfllsNulIflConAnswerlB.0.[ConAnswer1 1]] Between IlfllsNuIIflForInsll[O_PoIlSoc]I[Concentratlon11].- 0.1.[Forms]l[0_Po|I‘Soc]![Concentration1l] And IlfllsNuIlflForrns]![0_Po|lSoc]!|ConcentrationZI].1.79769313466231E+306.[Forms]![0_PolISoc]l[Concentratlon2]]] AND lfllsNullflPermcability_8l]],0.[Permeahility_Sl]]] Between llfllsNullflFormsl![0_PollSoc]l|PerIneabllfly1I].- 0.1.[Fonns]![0_PoIlSoc]![PcrmeabllitylI] And lIllIsNull[|Fonns|![0_Pol!Soc]![PermeabIIIIyZI].119769313466231E+306.[Forms]!|0_PoI!Socll|Penneablllty2]]] AND [[IlfilsNuIlflHumidlty]].lI.[Humldlty||] Between Ilt[|sNulI[[Forrns]!|0_PolJSocI!|RH10,-0.1.[Forrns]![0_PolISoc]l[RI-I1]] And IIIIIsNuIIflForms]![O_PoUSoc]!|RH2]].1.79769313486231EI308.[Forms]![0_PollSocI![RH2]]] AND [lIt[lsNull[|Year]].0.[Year|]] Between Ill[|sNull[[Forms]![O_PolISoc|l|Year1fl.0.[Fonns|![0_PolISoc]![Year1I] And llfllsNulIflForms]![0_PoIISoc]![Year21].9999.[Forms|l|0_PolI‘Soc]l|Ycar2]]] AND [[lIl[lsNullflTempCSlfl.0.l'l'empCS|m 5 ram WWW”. Figure 37. Standard Query "SQL View" 89 1 I. Ill Ila! 1‘ v r“ .n SUMMARY AND CONCLUSIONS The beginning of this thesis includes a summary of the scientific investigations of Zobel, Gilbert, Delausses, Giacin and Hernandez. These four, madern, mass transfer, groups have been major contributors to published data in recent years. A database was developed to calculate mass transfer (permeability, diffusion, and .sorption. coefficients), and their corresponding partial pressure gradient values. Through it information has been made readily accessible to technical and product/packaging professionals. For effective comparison purposes, all mass transfer and partial pressure gradient values were converted into standard international units. It includes the values with their respective literature reference. The database can be separated into three major sections. The main table is divided into appropriate fields which store all normalized data as standard international units. This table cannot be seen by the ‘user, and can be accessed for change and additions only by a”) administrator. The input reference section consists of mass transfer, Exertial pressure gradient, polymer, penetrant, organic 9O compound class, test methods, and literature references. This one page input reference form is the "conversion calculator" of the database, and can be accessed only by the administrator. All results of the input reference are converted into standard international units before being transferred into the main table for later query. The query section performs sorting of the main table's data fields. It. is divided into standard and advanced query levels. For each numerical query, the user can choose to enter a range, a minimum or maximum value, or nothing in both levels of querying. The choice of polymer or permeant, either specific or compound class, is required to start a standard query. Partial pressure gradient, permeability, relative humidity, temperature, cm: year are included in the possible numerical limitations. The advanced query empowers the user to sort by title, author, reference, testing method for permeability, diffusion, and solubility. It also permits the user to numerically limit 'the data. by