SYNOPSISA review of theoretical equations of state for polymer liquids is presented. Characteristic parameters for six equations of state, as well as parameters for the empirical Tait equation, are given for 56 polymers where pressure-volume-temperature (PVT) data over a wide range of conditions could be found in the literature. New PVT data are presented for four polymers: poly (epichlorohydrin ) , poly (e-caprolactone) , poly (vinyl chloride), and atactic polypropylene. All six equations of state provide adequate fits of the experimental specific volume data for the 56 polymers in the low pressure range (up to 500 bar). The modified cell model of Dee and Walsh, the Simha-Somcynsky hole theory, the Prigogine cell model, and the semiempirical model of Hartmann and Haque, were all found to provide good fits of polymer liquid PVT data over the full range of experimental pressures. The FloryOrwoll-Vrij and the Sanchez-Lacombe lattice-fluid equations of state were both significantly less accurate over the wider pressure range. 0 1993 John Wiley & Sons, Inc. I NTRO DUCT10 NPressure-volume-temperature ( PVT ) relationships for polymeric materials is a subject of importance to polymer scientists and engineers, particularly from a process design standpoint. Equally important is the need for equations of state that adequately described this behavior over a wide range of temperature and pressure. This article presents a review of several equations of state for polymers in the liquid state (i.e., above the melting point for crystalline polymers or above the glass transition for amorphous polymers). A summary of available PVT data for polymer liquids from the literature is also presented. In addition, previously unpublished PVT data for poly( epichlorohydrin ) , poly( e-caprolactone ) , poly (vinyl chloride), and atactic polypropylene, are also made available. Finally, a useful compendium of the characteristic parameters for 6 different equations of state, as well as parameters for the em-

Solubility of gases in liquid polymers is treated theoretically using the lattice fluid model. Qualitatively, the model indicates that gas solubility should increase with molecular size as observed experimentally. In addition, the physical properties of the gas and polymer should dominate gas solubility with the gas-polymer interaction playing a secondary role. Using no adjustable parameters, gas solubilities can be quantitatively predicted for hydrocarbon and chlorinated hydrocarbon vapors in non-polar polymers. Good results are also obtained for polar gases (excluding alcohols) in polar polymers. Polar/non-polar combinations are not correlated as well, but the deviations are very systematic and suggest future directions for research.

where r10 and r20 are the reaction rates evaluated at bulk gas conditions.Literature Cited

Previously we have shown that the Lattice Fluid (LF) model can quantitatively predict, without adjustable parameters, gas solubilities for hydrocarbon and chlorinated hydrocarbon vapors in nonpolar polymers. For polar polymers, the model can also predict, with reasonable success, the solubilities of polar and aromatic vapors. However, the solubilities in polar/nonpolar combinations of gas and polymer are systematically overestimated. These are cases in which the geometric mean approximation for the interaction parameter is not expected to be valid. This paper demonstrates that with the addition of a simple empirical correlation for the interaction parameter based on Hansen's three‐dimensional solubility parameters, the LF model is then able to quantitatively predict solubilities in all types of gas/polymer systems (excluding strongly self‐associating systems, such as alcohols). No adjustable parameters are used; only the pure component equation‐of‐state and solubility parameters are required. © 1993 John Wiley & Sons, Inc.