１‐トリメチルシリル‐１‐プロピンと１‐フェニル‐１‐プロピンから構成されるコポリマーとブレンド膜の気体透過性の温度依存

Abstract

The temperature dependence of the gas permeation properties of poly (1-trimethylsilyl-1-propyne) [PMSP] /poly (1-phenyl-1-propyne) [PPP] blends and poly (TMSP-co-PP) films was studied. As PP content increases, the activation energies of permeation (Ep) and diffusion (ED) for various gases in these materials increase, but no distinct change in the heat of solution (ΔHs) is observed. The increase in Ep is due to an increase in ED. All ED values are positive, while all ΔHs values are negative. In pure PMSP, Ep is negative for most gases because |ED| is much smaller than |ΔHs|. When the PP content exceeds 40 vol% in poly (TMSP-co-PP), however, Ep becomes positive because |ED| is now larger than |ΔHs|. Furthermore, Ep decreases with increasing critical temperature (Tc) of the penetrants because ΔHs decreases more than ED increases. After storage in air, the gas permeabilities of thin PMSP/PPP (9 : 1) blend films are found to be much lower than those of thin poly (TMSP-co-PP) (9 : 1) films. However, no substantial difference between the activation energies of permeation in these aged blend and copolymer films is observed. The gas permeabilities of thin poly (TMSP-co-PP) films are reduced even further after thermal treatment.This permeability reduction is a consequence of a larger Ep in the heat-treated, copolymer films. Ep is higher because of an increase in ED due to densification of these films by thermal treatment.