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Vinyl‐addition type norbornene copolymer containing sulfonated biphenyl pendant groups for proton exchange membranes
Author(s) -
Chen Lie,
Wang Xiaofeng,
He Xiaohui,
Liu Shufang,
Chen Yiwang,
Zhou Weihua
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.37642
Subject(s) - membrane , polymer chemistry , sulfonic acid , copolymer , nafion , norbornene , thermal stability , methanol , materials science , solvent , biphenyl , chemistry , nuclear chemistry , polymer , organic chemistry , electrochemistry , composite material , biochemistry , electrode
The vinyl addition type copolymer poly(butoxymethylene norbornene‐ co ‐biphenyl oxyhexamethyleneoxymethylene norbornene) (P(BN/BphN)) was synthesized by using bis‐(β‐ketonaphthylimino)nickel(II)/B(C 6 F 5 ) 3 catalytic system. P(BN/BphN) was sulfonated to give sulfonated P(BN/BphN) (SP(BN/BphN)) with concentrated sulfuric acid (98%) as sulfonating agent in a component solvent. The ion exchange capacity (IEC), degree of sulfonation (DS), water uptake, and methanol permeability of the SP(BN/BphN)s were increased with the sulfonated time. The methanol permeability of the SP(BN/BphN) membranes was in the range of 1.8 × 10 −7 to 7.5 × 10 −7 cm 2 /s, which were lower than the value 1.3 × 10 −6 cm 2 /s of Nafion®115. The proton conductivity of SP(BN/BphN) membranes increased with the increase of IEC values, temperature, and water uptake. Water uptake of the SP(BN/BphN) membranes was lower than that of Nafion® 115 and leads to low proton conduction. Microscopic phase separation occurred in SP(BN/BphN) membrane and domains containing sulfonic acid groups were investigated by SEM and TEM. SP(BN/BphN) membranes had good mechanical properties, high thermal stability, and excellent oxidative stability. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013