Modeling solubilities of subcritical and supercritical fluids in polymers with cubic and non-cubic equations of state

Abstract

The original statistical associating fluid theory (CK-SAFT), Perturbed-Chain SAFT (PC-SAFT), Sanchez–Lacombe (SL) and Sako–Wu–Prausnitz (SWP) equations of state (EoS) are used to model the solubilities of subcritical and supercritical fluids such as N 2, C 2H 4, C 4H 10, iso-C 4H 10, CO 2 in molten, thermally softened or semicrystalline polymers. Classical van der Waals one-fluid mixing rule with only one adjustable binary parameter is used for all the models. Modeling results are compared with the experimental data for 21 binaries including 78 systems published in open literature. Good agreement can be obtained with the PC-SAFT and SL EoS where the polymers are molten or thermally softened. Moreover, SL EoS gives a reasonable representation of the sorption data for semicrystalline polymers but the results are less satisfactory when compared with amorphous polymer systems. The performance of the CK-SAFT is least satisfactory in most case. Furthermore, SWP EoS provides an encouraging results although it is only a simple cubic equation of state.