新しい分離膜 ポリ［１‐（トリメチルシリル）‐１‐プロピン］膜の気体透過性

Abstract

Studies on the gas permeability of poly [1- (trimethylsilyl) -1-propyne], PMSP, membrane which has the highest gas permeability of all polymeric membranes are reviewed. First of all, permeability, solubility and diffusion coefficients of gases of PMSP membranes were shown. However, the permeability coefficient of gases, for example, oxygen permeability reported in references differs remarkably like 2.6-10×10-7 [cm3 (STP) ·cm/cm2·sec·cmHg] at 25°C. This suggests that the condition of the PMSP membrane before gas permeability measurement influences the results. In the second part, phenomena of the decrease of the gas permeability is introduced in detail. The PMSP membrane has extraordinary large unrelaxed free volume and the property of sorption of non-volatile organic vapor even at the lowest vapor pressure such as 10-6 torr. These are the main factor for the decrease of the gas permeability. The degree of the decrease reported also differs. In the third part, the modification of the PM-SP and/or PMSP membranes by physical and chemical methods are reviewed ; laminate with other gas permeable thin membranes, filling with polyorganosiloxane or oligomers, and irradiation of ultraviolet light, low-temperature plasma treatment, graft polymerization on C-CH3, copolymerization with phenyl propyne. Especially, the filling of polydimethylsiloxane into the PMSP membrane is effective for the stabilization of the gas permeability against the physical aging, even in the filling of low concentration of less than 1 wt%.