Gas permeation properties of polymer membranes containing ethylene glycol monomers

Abstract

Copolymers based on glassy and rubbery units have been developed to take advantage of both domains to enhance solubility and diffusivity. In this study, a series of gas separation membranes from poly(ether sulfone)s containing ethylene glycol were synthesized via nucleophilic substitution polycondensation. The structures of copolymers were confirmed by proton nuclear magnetic resonance spectroscopy and Fourier transform infrared spectra. The permeability and selectivity of the membranes were studied at different temperatures of 25–55°C and pressures of 0.5–1.5 atm using single gases, such as carbon dioxide (CO2) and nitrogen (N2). Gas permeation measurements showed that copolymers with different content of poly(ethylene glycol) (PEG) exhibited different separation performances. For example, the membrane from polysulfone–PEG-20 containing 20 wt% PEG showed a better performance in terms of ideal selectivity over the other three copolymers membranes. The highest ideal CO2/N2 selectivity was 66.8 with CO2 permeability of 6.4 barrer at 1.5 atm and 25°C.