Polyimide ionomer containing superacid groups†
This work is respectfully dedicated to the memory of Prof. Dr Eishun Tsuchida, who was a Ph.D. supervisor of K.M. at Waseda University and encouraged him with this research.
Abstract
A novel sulfonated polyimide (SPI) copolymer containing pendant perfluorosulfonic acid groups was synthesized and their properties were investigated. 2-(2,4-Diaminophenoxy)-1,1,2,2-tetrafluoroethanesulfonic acid (5) was synthesized from 2,4-diaminophenol dihydrochloride via acetylation, perfluoroalkylation, and sulfonation. Polycondensation of 1,4,5,8-naphthalenetetracarboxylic dianhydride, monomer 5, and 3,5-bis(4-aminophenyl)-1H-1,2,4-triazole gave the title polyimide 6. The obtained polyimide copolymer 6 was soluble in polar organic solvents and its chemical structure and ion exchange capacity were confirmed by 1H and 19F NMR spectra. The copolymer 6 was thermally stable up to ca. 180°C and showed 6.6 × 10−4 S cm−1 of the proton conductivity at 80°C in water. Copyright © 2011 John Wiley & Sons, Ltd.
