| Abstract
| - An analysis of the empirical correlations that relate the solubility coefficient of gases at infinite dilution inglassy polymers to penetrant properties has been performed, by considering gas sorption as a succession ofthree steps: condensation of the penetrant, dissolution in the equilibrium polymeric phase, and departure ofthe system from equilibrium. The infinite dilution solubility coefficient is obtained from the contributions ofthe three steps, the first two of which involve standard equilibrium thermodynamics, while the latter requiresnonequilibrium considerations and is described by using the nonequilibrium lattice fluid (NELF) model. Thevarious terms have been evaluated for several gases in polycarbonate, polysulfone, poly(phenylene oxide),and poly(methyl methacrylate). It has been found that the largest term in the expression of solubility is dueto condensation, which explains the observed correlation between solubility and critical temperature, whilethe out of equilibrium contribution to solubility, which generally gives numerical values lower than thecondensation term, is in turn more strongly correlated to the penetrant critical volume.
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