An investigation on structural and gas transport properties of modified cross-linked PEG-PU membranes for CO2 separation

In this paper, modified poly(ethylene glycol)-polyurethane (PEG-PU) membranes were synthesized applying thiol-epoxy click polymerization to separate CO2 (the most important greenhouse gas) form light gases. PEG was initially reacted with isophorone diisocyanate (IPDI) and the NCO-terminated prepolymer was end-capped with glycidol to form epoxy-terminated prepolymer (EPU). The cross-linked membranes were eventually obtained through thiol-epoxy click polymerization reaction using a tetrathiol cross-linker (PETMP) in presence of poly(ethylene glycol) diglycidyl ether (PEGDE). The prepared membranes were characterized by ATR-FTIR, DSC, TGA and tensile analyses. The best fabricated membrane was chosen and named EMT2 which exhibited promising structural, thermal and mechanical properties. It was then employed for further gas transport properties studies. Permeability, solubility, and diffusion coefficients of CO2, N2, CH4, and O2 gases over wide ranges of temperature (308–348 K) and pressure (2–16 bar) were investigated. It was found that EMT2 membrane offers higher CO2 permeability coefficients, compared to some other PEG-PU membranes in the literature fabricated with a same length of soft segment. [Display omitted] •Improved cross-linked PEG-PU membranes were fabricated using thiol-epoxy click polymerization.•A tetrathiol cross-linker (PETMP) was employed as an initiating core.•Gel content and cross-linked density of the fabricated membranes were increased.•Obtained structural and gas transport properties were promising for CO2 separation applications.