Temperature dependence and energetics of the equilibrium sorption of water vapor in glassy polyacrylonitrile

Ranade, G. R.; Stannett, V.; Koros, William J.

doi:10.1002/app.1980.070251004

Cited by 20 publications

(10 citation statements)

References 9 publications

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“…Calculations of the isosteric enthalpy of sorption in several gas-polymer systems confirm that the gaspolymer affinity is reduced with increasing sorbed gas concen trations (24,25,26). The change in the isosteric enthalpy of sorption is a result of the changes in the polymer matrix induced by the presence of the sorbed gas.…”

Section: Solubility Coefficientmentioning

confidence: 74%

Sorption and Transport in Glassy Polymers

Raucher¹,

Sefcik²

1983

ACS Symposium Series

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The gas-polymer-matrix model for sorption and transport of gases in polymers is consistent with the physical evidence that; 1) there is only one population of sorbed gas molecules in polymers at any pressure, 2) the physical properties of poly mers are perturbed by the presence of sorbed gas, and 3) the perturbation of the polymer matrix arises from gas-polymer interactions. Rather than treating the gas and polymer separately, as in previous theories, the present model treats sorp tion and transport as occurring through a gas -polymer matrix whose properties change with compo sition.Simple expressions for sorption, diffu sion, permeation and time lag are developed and used to analyze carbon dioxide sorption and trans port in polycarbonate.Nonlinear, pressure-dependent sorption and transport of gases and vapors in glassy polymers have been observed fre quently. The effect of pressure on the observable variables, solubility coefficient, permeability coefficient and diffusion timelag, is well documented (1, 2). Previous attempts to explain the pressure-dependent sorption and transport properties in glassy polymers can be classified as "concentration-dependent" and "dual-mode" models.While the former deal mainly with vapor-polymer systems (_1) the latter are unique for gas-glassy polymer systems (2).The concentration-dependent models attribute the observed pressure dependence of the solubility and diffusion coefficients to the fact that the presence of sorbed gas in a polymer affects the structural and dynamic properties of the polymer, thus affecting the sorption and transport characteristics of the system (3). On the other hand, in the dual-mode model, the pressure-dependent sorption and transport properties arise from a

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Section: Solubility Coefficientmentioning

confidence: 74%

Sorption and Transport in Glassy Polymers

Raucher¹,

Sefcik²

1983

ACS Symposium Series

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“…The value ⌬H C ϭ Ϫ5.9 kJ/mol (Ϫ1.4 kcal/mol) is by nearly one order of magnitude smaller than is the analogous value determined by Ranade et al 24 for PAN (Ϫ10.3 kcal/mol).…”

Section: Henry Termmentioning

confidence: 51%

“…24 Recent investigations by Dlubek et al 21 of the property of water in local free volumes of a specific, hydrophilic polyimide by positron annihilation lifetime spectroscopy support this view.…”

Section: Langmuir Termmentioning

confidence: 96%

“…From thermodynamic considerations, K is related to the molecular partition function for the primarily adsorbed molecules and to their heat of sorption 10 leading with respect to its temperature dependence to the familiar van't Hoff expression 24 :…”

Section: Langmuir Termmentioning

confidence: 99%

“…24 Nonlinear fitting of eq. (3) to the data of K in Table I (r ϭ 0.898) yields (Ϯ95% confidence limits):…”

Section: Langmuir Termmentioning

confidence: 99%

See 2 more Smart Citations

Temperature dependence of the water-sorption isotherms of wool

Wortmann¹,

Augustin²,

Popescu³

2000

J. Appl. Polym. Sci.

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Acrylonitrile and Acrylonitrile Polymers

Wu¹

2001

Encyclopedia of Polymer Science and Technology

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Acrylonitrile is a versatile and reactive monomer that can be polymerized under a wide variety of conditions and copolymerized with an extensive range of other vinyl monomers because of its polar nature and reactivity. Because of the difficulty of melt processing the acrylonitrile homopolymer, acrylonitrile is usually copolymerized to achieve a desirable thermal stability, melt flow, and physical properties. Acrylonitrile‐containing polymers are used in the areas of textile fibers, carbon fiber percursors, adhesives, binders, antioxidants, medicines, dyes, electrical insulations, emulsifying agents, graphic arts materials, insecticides, leather, paper, plasticizers, soil‐modifying agents, solvents, surface coatings, textile treatments, viscosity modifiers, azeotropic distillations, artificial organs, lubricants, asphalt additives, water‐soluble polymers, hollow spheres, cross‐linking agents, and catalyst treatments. Styrene is the largest volume acrylonitrile comonomer for thermoplastic applications. Styrene–acrylonitrile (SAN) copolymers are inherently transparent plastics with high heat resistance and excellent gloss and chemical resistance. They are also characterized by good hardness, rigidity, dimensional stability, and load‐bearing strength. In general, the styrene component of SAN resins offers clarity, stiffness, and processibility, while the acrylonitrile provides chemical and heat resistance. Because of their inherent transparency, SAN copolymers are most frequently used in clear application. These optically clear materials can be readily processed by extrusion and injection molding, but they lack real impact resistance. SAN resins show considerable resistance to solvents and are insoluble in carbon tetrachloride, ethyl alcohol, gasoline, and hydrocarbon solvents. Polar solvents dissolve SAN. The properties of SAN are significantly altered by water absorption. Commercially, SAN is manufactured by three processes: emulsion, suspension, and continuous mass polymerization. More than 75% of the SAN resin produced is believed to be used captively for acrylonitrile–butadiene–styrene compounding and in the production of acrylonitrile–styrene–acrylate and acrylonitrile–EPDM–styrene weatherable copolymers. SAN resins appear to pose few health problems, and they have been approved by the FDA for direct food contact. Copolymers of acrylonitrile and methyl acrylate and terpolymers of acrylonitrile, styrene, and methyl methacrylate are used as barrier polymers. Acrylonitrile multipolymers containing indene; methyl methacrylate, and α‐methylstyrene are used as poly(vinyl chloride) modifiers for heat distortion temperature and processibility improvement.

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Temperature dependence and energetics of the equilibrium sorption of water vapor in glassy polyacrylonitrile

Cited by 20 publications

References 9 publications

Sorption and Transport in Glassy Polymers

Sorption and Transport in Glassy Polymers

Temperature dependence of the water-sorption isotherms of wool

Acrylonitrile and Acrylonitrile Polymers

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