Permeation properties to CO2 and N2 of poly(ethylene oxide)-containing and crosslinked polymer films

Poly(ethylene oxide) (PEO)-containing and crosslinked polymer films were prepared from mixtures of poly(ethylene glycol) dimethacrylate (DM), 2,2-bis(4-methacryloxy polyethoxy phenyl)propane and poly(ethylene glycol) methyl ether methacrylate (MM) by photo polymerization. Average numbers of repeating unit of ethylene oxide for DM and MM, n were ranged 9-69 and 9 or 23, respectively. Permeation properties toward CO2 and N-2 of the polymer films were investigated in connection with their characteristics. The films showed large permeability coefficients of CO2, P-CO2, and high permeability ratios of CO2 over N-2, P-CO2/P-N2. For example, P-CO2, was 510 Barrer (1 Barrer=10(-10) cm(3)(STP) cm/(cm(2) s cmHg)) with P-CO2/P-N2 of 36 for DM69/MM9(90/10) film at 50 degrees C, which was prepared from the mixture of DM (n=69) and MM (n=9) in the weight ratio of 90/10. The highest P-CO2\P-N2 of 69 was obtained at 25 degrees C for DM14/MM9(90/10) film with P-CO2 of 62 Barrer. The permeability coefficient, diffusion coefficient, D, and solubility coefficient, S, increased with an increase in n. The large P-CO2 was attributed to large D-CO2, and the high P-CO2/P-N2 to the high solubility selectivity of CO2/N-2. The films with much longer blocks of PEO were partially crystallized at low temperatures, resulting in a large decrease in P, D and S. The values of log(D) were well correlated with fractional free volumes. (C) 1999 Elsevier Science B.V. All rights reserved.