Influence of TRIS-based co-monomer on structure and gas transport properties of cross-linked poly(ethylene oxide)

3-[Tris-(trimethylsiloxy)silyl] propyl acrylate (TRIS-A) was copolymerized with poly(ethylene glycol) diacrylate (PEGDA), and the gas transport and physical properties of the resulting copolymers were characterized. Introduction of TRIS-A led to increased polymer fractional free volume and strong broadening of the glass–rubber relaxation without a significant shift in glass transition temperature in samples containing up to 80 wt% TRIS-A. Gas permeability increased significantly as TRIS-A content increased: for instance, addition of 80 wt% TRIS-A increased CO2 permeability from 110 to 800 barrer. The strongly non-polar character of TRIS-A, however, resulted in progressively lower CO2 affinity for the polymer network, leading to decreased CO2/light gas selectivity with increasing TRIS-A content.