GAS PERMEATION AND SORPTION IN BROMINATED POLY(1-TRIMETHYLSILYL-1-PROPYNE) MEMBRANE

Brominated poly(1-trimethylsilyl-1-propyne) (Br-PMSP), which was prepa red by immersing a poly(1-trimethylsilyl-1-propyne) membrane in bromin e water, had a new endothermic peak between 70-degrees-C and 80-degree s-C in its DSC curves. After storage in air at room temperature, the e ndothermic peak shifted to the low temperature side with time, and occ urred between 30-degrees-C and 40-degrees-C. A distinct change in slop es near the endothermic temperature determined by the DSC analysis was observed in the Arrhenius plots of the permeability coefficients for various gases in all Br-PMSP membranes. However, the slope's change di d not clearly appear with storage under the same conditions. The Br-PM SP membrane had a pressure-dependence of the permeability coefficients not only below the endothermic temperature, but also above one. The s orption behavior for propane in the Br-PMSP membrane was similar to th at for other glassy polymers, and there was little change in the sorpt ion behavior with time. In the case of carbon dioxide, a different beh avior was observed at first; that is, the same isotherm shape in glass y polymers appeared below 20 atm, but it showed an upward curve above that. After storage in air, the upward behavior disappeared, and the i sotherm showed the general shape in glassy polymers. (C) 1994 John Wil ey & Sons, Inc.