Improved performance of sulfonated polyarylene ethers for proton exchange membrane fuel cells

The performances of polyarylene ethers and sulfonated polyarylene ethers having different backbone structures and sulfonated position were comparatively investigated focusing on the determination of the proton conductivity, thermal and chemical stability. The results indicated that the sulfone groups in polymer backbones are highly thermal stable. The sulfonic acid group at the metasulfone position had better thermal, chemical stability and higher proton conductivity than those at the ortho-ether and ortho-sulfone position. The series of stability is meta-sulfone sulfonated polyphenyl sulfone (SPSU) > ortho-sulfone SPSU >> ortho-ether SPSU. The knowledge of these parameters will lead to the synthesis of sulfonated arylene main-chain ionomers that are optimized for application in fuel cells. Also different sulfonated polyphenyl sulfone-4,4'-biphenol/polybenzimidazole (SPSU-BP/PBI) acid-base crosslinked blend membranes have been studied. The SPSU/PBI crosslinked blend membranes had better mechanical stability than their parent membrane while maintaining good thermal stability and having suitable proton conductivity. Copyright (c) 2006 John Wiley & Sons, Ltd.