EFFECT OF METHYL SUBSTITUENTS ON PERMEABILITY AND PERMSELECTIVITY OF GASES IN POLYIMIDES PREPARED FROM METHYL-SUBSTITUTED PHENYLENEDIAMINES

被引:249
作者
TANAKA, K
OKANO, M
TOSHINO, H
KITA, H
OKAMOTO, KI
机构
[1] Department of Advanced Materials Science and Engineering, Faculty of Engineering, Yamaguchi University, Ube, 755, Yamaguchi
关键词
PERMEATION AND SOLUBILITY OF GASES IN POLYIMIDES PREPARED FROM METHYL-SUBSTITUTED PHENYLENEDIAMINES; POLYIMIDES FROM METHYL-SUBSTITUTED PHENYLENEDIAMINES; PERMEATION OF GASES IN; DIFFUSION OF GASES IN POLYIMIDES;
D O I
10.1002/polb.1992.090300813
中图分类号
O63 [高分子化学(高聚物)];
学科分类号
070305 ; 080501 ; 081704 ;
摘要
Permeability and solubility coefficients for H-2, CO2, O2, CO, N2, and CH4 in polyimides prepared from 6FDA and methyl-substituted phenylenediamines were measured to investigate effects of the substituents on gas permeability and permselectivity. The methyl substituents restrict internal rotation around the bonds between the phenyl rings and the imide rings. The rigidity and nonplanar structure of the polymer chain, and the bulkiness of methyl groups make chain packing inefficient, resulting in increases in both diffusion and solubility coefficients of the gases. Polyimides from tetramethyl-p-phenylenediamine and trimethyl-m-phenylenediamine display very high permeability coefficients and very low permselectivity due to very high diffusion coefficients and very low diffusivity selectivity, as compared with the other polyimides having a similar fraction of free space. This suggests that these polyimides have high fractions of large-size free spaces.
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页码:907 / 914
页数:8
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