Preparation of Cation-exchange Membranes from Polylsulfone with Poly （sodium p-styrenesulfonate） Graft Chains

Abstract

Cation-exchange membranes （CEMs） were prepared from polysulfone （PSF）-based graft copolymers with graft chains of poly（sodium styrene sulfonate）. The graft-copolymers were synthesized by grafting ethyl p-styrenesulfonate （EtSS） on macro-initiators of chloromethylated PSF with different chloromethyl （CM） groups, thus changing the EtSS content in the polymers by using atom transfer radical polymerization. The transport number of the CEM （CM content ＝ 8.4 mol ％, and EtSS ratio ＝ 46 wt.％） was 0.98, almost the same as that of a commercial CEM, Neosepta® CMX （ASTOM Corp., Japan）, 0.98. The membrane resistance of the PSF-based CEM was 2.3 Ω・cm², and lower than that of CMX, 3.0 Ω・cm².