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Gas Permeation Properties of Copolyimides from 1,4‐Bis(3,4‐dicarboxyphenoxy)benzene Dianhydride and 2,2‐Bis(3,4‐ dicarboxyphenyl)hexafluoroisopropane Dianhydride
Author(s) -
Li Yuesheng,
Ding Mengxian,
Xu Jiping
Publication year - 1997
Publication title -
polymer international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.592
H-Index - 105
eISSN - 1097-0126
pISSN - 0959-8103
DOI - 10.1002/(sici)1097-0126(199701)42:1<121::aid-pi689>3.0.co;2-0
Subject(s) - permeation , benzene , selectivity , permeability (electromagnetism) , polymer chemistry , materials science , polymer , chemistry , organic chemistry , membrane , composite material , catalysis , biochemistry
A series of aromatic copolyimides was prepared from 1,4‐bis(3,4‐dicarboxyphenoxy)benzene dianhydride (HQDPA) and 2,2‐bis(3,4‐dicarboxy‐phenyl)hexafluoroisopropane dianhydride (6FDA) with 3,3′‐dimethyl‐4,4′‐methyl‐ene dianiline (DMMDA) by a chemical imidization. The gas permeability coefficients of the copolyimides to H 2 , CO 2 , O 2 , N 2 and CH 4 were measured under 7atm. pressure. The fractional free volume of 6FDA–DMMDA is larger than that of HQDPA–DMMDA, while the chain segmental mobility of 6FDA–DMMDA is lower than that of HQDPA–DMMDA. The gas permeability of 6FDA–DMMDA is much higher than that of HQDPA–DMMDA but the perm‐selectivity of 6FDA–DMMDA for H 2 , CO 2 , O 2 , N 2 over CH 4 is lower than that of HQDPA–DMMDA. The experimental values of the gas permeability coefficients of the copolyimides are in satisfactory agreement with the values estimated from the gas permeability coefficients of the constituent homopolyimides and their weight fractions. © of SCI.