Gas and Vapor Solubility in Cross-Linked Poly(ethylene Glycol Diacrylate)

Polymers containing poly(ethylene glycol) (PEG) have been investigated for CO2 removal from mixtures with light gases such as CH4, N2, and H2 because of the good affinity of PEG for CO2. In this study, the solubilities of CO2 and several hydrocarbons (CH4, C2H4, C2H6, C3H6, and C3H8) were determined as a function of gas fugacity (i.e., pressure) at temperatures ranging from −20 °C to 35 °C in cross-linked amorphous poly(ethylene glycol) diacrylate (XLPEGDA), which was prepared by UV photopolymerization of poly(ethylene glycol) diacrylate and contains about 82 wt % PEG. Sorption isotherms were described using the Flory−Huggins model. Unlike sorption in nonpolar rubbery polymers, solubility of gases such as CO2 and olefins in polar XLPEGDA do not vary systematically based on parameters used conventionally to characterize gas condensability such as critical temperature (Tc) or (Tc/T)2, so a new model is proposed to correlate the data. CO2 exhibits the lowest Flory−Huggins interaction parameter (i.e., χ) valu...