An Equation of State-Based Modeling Approach for Estimating the Partial Molar Volume of Penetrants and Polymers in Binary Mixtures

Partial molar volumes (PMVs) of highly soluble hydrocarbon gases and polymers in macromolecular mixtures have been estimated by using a model-based methodology that utilizes binary gas/polymer sorption data. It has been shown that the PMVs of the penetrants and polymers as well as other volumetric properties (e.g., molar volume per repeating unit and volumetric thermal expansion coefficients) can be accurately calculated over a wide range of temperatures and pressures. The advantages of the proposed methodology are that it relies on available experimental sorption data of gases in polymers and an equation of state, provides an attractive alternative to the more onerous experimental procedures of densimetery and sorptive dilation for obtaining volumetric data of polymeric mixtures, and it can be extended to multicomponent systems.