310. Solution and diffusion of gases in polystyrene at high pressures

Newitt, D. M.; Weale, K. E.

doi:10.1039/jr9480001541

Cited by 55 publications

(30 citation statements)

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“…Experimental evidence reveals that small penetrants (like gases) require such a small amount of free volume to diffuse that the break is either minor or even negligible. 90 Because of this, the extra frozen-in free volume created in a glassy polymer does not significantly raise the diffusion coefficient as it does for a large penetrant that requires more free volume for transport.…”

Section: Interpretation Of MD Resultsmentioning

confidence: 99%

Application of free‐volume theory to self diffusion of solvents in polymers below the glass transition temperature: A review

Ramesh

Davis

Zielinski

et al. 2011

J Polym Sci B Polym Phys

109

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Theories based on free-volume concepts have been developed to characterize the self and mutual-diffusion coefficients of low molecular weight penetrants in rubbery and glassy polymer-solvent systems. These theories are applicable over wide ranges of temperature and concentration. The capability of free-volume theory to describe solvent diffusion in glassy polymers is reviewed in this article. Two alternative free-volume based approaches used to evaluate solvent self-diffusion coefficients in glassy polymer-solvent systems are compared in terms of their differences and applicability. The models can correlate/predict temperature and concentration dependencies of the solvent diffusion coefficient. With the appropriate accompanying thermodynamic factors they can be used to model concentration profiles in mutual diffusion processes that are Fickian such as drying of coatings. The free-volume methodology has been found to be consistent with molecular dynamics simulations. INTRODUCTIONThe diffusion of small molecules in polymers is of considerable practical importance and has been studied extensively. Diffusion theories based on the free-volume concept have been used extensively to correlate and predict solvent self-diffusion coefficients in rubbery polymersolvent systems.1-6 These methods provide accurate predictions over a wide range of temperatures and concentrations above the glass transition temperature of the pure polymer. As polymer solutions are cooled over practical time scales, the rate of cooling exceeds the rate of relaxation of the polymer, and a nonequilibrium state referred to as the glassy state results. This phenomenon causes volume to be trapped in the polymer in excess of that expected at equilibrium. Free-volume theory presumes that this extra volume is available to facilitate mass transport in the glassy state. Based on this concept, the original free-volume theory was adapted to describe the diffusion of a trace amount of a solvent in a glassy polymer, 7,8 and it was further extended to describe self-diffusion below the mixture glass transition temperature at finite concentrations of the solvent.

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Section: Interpretation Of MD Resultsmentioning

confidence: 99%

Application of free‐volume theory to self diffusion of solvents in polymers below the glass transition temperature: A review

Ramesh

Davis

Zielinski

et al. 2011

J Polym Sci B Polym Phys

109

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show abstract

“…Other investigators ( 2 to 4 ) found that Henry's Law held up to at least 100 atm. (nitrogen, methane with polyethylene) and possibly ( 5 ) up to 300 atm. (nitrogen, hydrogen with polystyrene).…”

Section: Effect Of Pressure On Gas Solubilities and Diffusivitiesmentioning

confidence: 99%

Diffusion and solution of gases into thermally softened or molten polymers: Part II. Relation of diffusivities and solubilities with temperature pressure and structural characteristics

Durrill

Griskey

1969

AIChE Journal

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Solubilities and diffusivities of various gases (helium, nitrogen, carbon dioxide, argon, neon, krypton, and monochlorodifluoromethane) in molten or thermally softened polymers (polyethylene, polypropylene, polyisobutylene, polystyrene, and polymethylmethacrylate) have been correlated with structural characteristics, temperature, and pressure. Temperature dependence of both Henry's Law constants and diffusivities were of the Arrhenius equation form. No appreciable effect of pressure was found for either Henry's Law constants or diffusivities up to 300 atm. Earlier correlations for Henry's Law constants in solid polymer systems were found to be inapplicable for molten and thermally softened polymers. New correlations were developed individually for the latter systems. The correlating factor used was the gos LennardJones force constant. Existing correlations for diffusivities were also found not to apply to molten and thermally softened systems. New correlations were again developed on an individual polymer basis. These related diffusivity to gas Lennard-Jones collision diameter or molecular diameter. Generalized correlations were also developed that held for a number of polymers.These were for both Henry's Law constants and diffusivities.In an earlier paper (1) solubility and diffusivity data were presented for gases absorbed into molten or thermally softened polymer systems. The intent of this paper is to use these data together with other literature information ( 2 to 10) to correlate solubilities and difFusivities with temperature, pressure, and gas and polymer structural characteristics for molten or thermally softened polymer systems.

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“…These investigators utilized high clude the values of Newitt and Weale (1948) for hydrogen, pressure sorption experiments in which solubility and difnitrogen, carbon dioxide, and ethylene for 403" to 463°K fusivity data were simultaneously obtained. Duda and and 80 to 300 atm.…”

Section: Conclusion and Significancementioning

confidence: 99%

Solubility of gases and liquids in molten polystyrene

Stiel

Harnish

1976

AIChE Journal

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Experimental solubility data have been obtained for sixteen organic solutes in molten polystyrene by a gas chromatographic procedure for temperatures from 408° to 503°K and pressures to 4 atm. The effects of diffusion and adsorption of the solute on the substrate were considered. The Henry's law constants resulting from this study and those obtained by other investigators were related to the reduced temperature. The effect of pressure on the Henry's law constants is also discussed, and a relationship is presented for the heat of solution.

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310. Solution and diffusion of gases in polystyrene at high pressures

Cited by 55 publications

References 0 publications

Application of free‐volume theory to self diffusion of solvents in polymers below the glass transition temperature: A review

Application of free‐volume theory to self diffusion of solvents in polymers below the glass transition temperature: A review

Diffusion and solution of gases into thermally softened or molten polymers: Part II. Relation of diffusivities and solubilities with temperature pressure and structural characteristics

Solubility of gases and liquids in molten polystyrene

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