Carboxylic acid functionalized fluorinated sulfonated poly(arylene ether sulfone) copolymers with enhanced oxidative stability

By Mukherjee, Rajdeep; Banerjee, Susanta; Komber, Hartmut; Voit, Brigitte
Published in Journal of Membrane Science NULL 2016

Abstract

Abstract Carboxylic acid functionalized TPQSH-COOH-XX copolymers were synthesized to investigate their proton exchange membrane properties. This new series of copolymers was prepared by copolymerization of a -COOH moiety containing diphenol monomer, 2-[bis-(4-hydroxy-phenyl)-methyl]-benzoic acid (TP-COOH), with two dihalide monomers, 4,4?-bis(4?-fluoro-3?-trifluoromethylbenzyl)biphenyl (QBF) and 3,3?-disodiumsulfonyl-4,4?-dichlorodiphenylsulfone (SDCDPS), in different mole ratios. The structure of the copolymers (TPQSH-COOH-XX) and of the homopolymer (TPQ-COOH) was analyzed by spectroscopic techniques. The copolymers TPQSH-COOH-XX with different percentage of -SO3H groups showed in {TEM} images a clear phase separated morphology with ionic clusters of sizes from 5 to 80 nm. All the -COOH functionalized ionomer membranes showed good mechanical properties with enhanced oxidative stability and high dimensional stability. The membranes exhibited high water uptake and swelling due to high {IEC} values (1.38-1.96 mequiv/g) and the presence of -COOH groups. The copolymers showed high proton conductivity (55-116 mS/cm at 80

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