PERMEATION OF GASES IN POLY[1-(TRIMETHYLSILYL)-1-PROPYNE]

Permeation behavior of oxygen, nitrogen, carbon dioxide, methane, isobutane, and five inert gases in poly left bracket 1-(trimethylsilyl)-1-propyne right bracket was studied at 30, 50, and 70 degree C in the pressure region below 1 atm. The sample films were prepared by prolonged solvent-casting at room temperature, and the cast films were leached in methanol until use. For oxygen and for inert gases, the permeability coefficients P OVER BAR increased slightly with increasing pressure at lower pressures and leveled off in the middle and high pressure regions. The time lag, on the other hand, decreased with increasing pressure at lower pressures and approached a limiting value at higher pressures. Sorption measurements for isobutane were made at 25 degree C; some excess volume of the polymer film was suggested by the results. The physical aging effect on gas permeabilities is discussed in terms of consolidation of the excess volume with the increase of total time under vacuum.