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Mixed gas and pure gas transport properties of copolyimide membranes
Author(s) -
Chen Xiao Yuan,
Kaliaguine Serge
Publication year - 2012
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.37728
Subject(s) - permeation , gas separation , diamine , differential scanning calorimetry , thermogravimetric analysis , polymer chemistry , membrane , materials science , fourier transform infrared spectroscopy , copolymer , chemical engineering , polymer , chemistry , organic chemistry , thermodynamics , biochemistry , physics , engineering
Copolyimides were synthesized from dianhydride of 4,4′‐(hexafluoroisopropylidene)diphthalic anhydride (6FDA) with various diamine contents of 4,4′‐oxydianiline (ODA) and 2,3,5,6‐tetramethyl‐1,4‐phenylenediamine (TeMPD) by chemical imidization in a two‐step procedure. Polyimides (PIs) were characterized using thermogravimetric analysis, Fourier transform infrared spectroscopy, differential scanning calorimetry, as well as specific volume and free volume. The gas transport properties for pure gas and blends of CO 2 and CH 4 for the homopolymers and 6FDA‐ODA/TeMPD copolymers were investigated at 35°C and 150 psi pressure. In pure gas permeation, permeability of CO 2 and CH 4 increased with increasing TeMPD content in the diamine moiety, whereas the ideal selectivity decreased with increasing TeMPD content. In the mixed gas permeation, permeabilities and separation factor were measured as a function of CO 2 feed molar fraction for five PI membranes. The behavior of pure gas and mixed gas permeabilities and separation factor of CO 2 /CH 4 mixtures as the chemical nature of the diamine and the CO 2 molar fraction in the feed gas were varied and are discussed in detail. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2013