Semi-IPN Asymmetric Membranes Based on Polyether Imide (ULTEM) and Polyethylene Glycol Diacrylate for Gaseous Separation

Semi-interpenetrating polymer networks (semi-IPN) formed with commercial polyether imide (ULTEM (R), PEI) and poly (ethylene glycol) diacrylate (PEGDA) were used to make asymmetric membranes. The effect of increasing amount of PEGDA on the bulk and the gas separation properties of semi-IPN membranes were studied. The formation of IPNs was confirmed by Fourier Transform Infra Red (FT-IR) spectroscopy. The 5%. weight loss temperature decreased and the percent weight loss of the first step increased with increase in the PEGDA content, which indicated the incorporation of more poly (ethylene glycol) (PEG) segments to the semi-IPNs. The microscopic experiments revealed the change in morphology with change in PEGDA content. The Scanning electron micrographs exhibited typical finger-like voids in the sub layer, which is characteristic morphology of asymmetric membranes. The increase in PEGDA content up to 5.7 wt %, increased the CO2/N-2 selectivity of the semi-IPN after which the selectivity decreased and permeance increased. Although, the increase in the polar poly (ethylene glycol) molecules is expected to render better CO, selectivity, the performance of the membrane was found to decrease as PEGDA content exceeded 5.7% for the given ratio. (c) 2008 Wiley Periodicals, Inc. J Appl Polym Sci 110: 3606-3615, 2008