Carbon Dioxide Permselectivity of Membranes of Copolymer of Vinyl Ether with a Tetraethylene Glycol Side Group and Vinyl Ether with a Methacrylate Side Group

Abstract

Novel poly(vinyl ether)s with tetraethylene glycol and methacrylate side groups [poly(TetraEGMVE-VEEM)] were synthesized by the copolymerization of TetraEGMVE with VEEM. The free-standing membranes of poly(TetraEGMVE-VEEM)s were prepared by thermal crosslinking between the methacrylate units. Membranes of poly(TetraEGMVE-VEEM) with 2:1 composition ratio showed high CO₂ permeability and CO₂/N₂ selectivity, whose P_CO2 and P_CO2/P_N2 were 250 barrer and 52, respectively. The P_CO2 of membranes of poly(TetraEGMVE-VEEM) with 4:1 composition ratio was 320 barrer, which is larger than that with 2:1 composition ratio. This difference is caused by the number of crosslinking points in the polymer matrix. The CO₂ permeability of poly(TetraEGMVE-VEEM) is higher than that of poly(vinyl ether) having diethylene glycols as a side chain. This high permeability originates from the high diffusivity of CO₂ in the membranes.