Preparation, structure, and pervaporation performance of poly(amide–imide)‐sulfonated polyimide composites

Abstract

ABSTRACTPoly{[4,4′‐bisdiphenyl‐2,2′‐disulfonic acid]imide‐1,3‐bis(3,4‐dicarboxyphenoxy)benzene} was synthesized via polycondensation and subsequent thermal imidization in m‐cresol:triethylamine. The obtained polymer and its composites with aromatic poly(amide–imide) obtained through polycondensation of 4‐chloroformyl‐(N‐p‐chloroformylphenyl)phthalimide and 4,4′‐diaminodiphenyl ether were investigated by use of nuclear magnetic resonance, thermogravimetric analysis, dynamic mechanical analysis, differential scanning calorimetry, Fourier transform infrared spectroscopy, scanning electron microscopy, and X‐ray diffraction analysis. Transport properties of composite films were studied during pervaporation of water–alcohol mixtures. On the basis of the data obtained, suggestions on the structure of materials and its influence on transport and other physical properties were made. The addition of 30 wt % of sulfonated polyimide to the poly(amide–imide) matrix enhances its separation factor in the process of separation of an azeotrope water/ethanol mixture by four times while permeability remains unchanged. The methanol permeability increases with an increase of the mass fraction of sulfonated polyimide in the composite film. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48197.