Abstract: Bisphenol A type polysulfone (PSF) and 1, 4-dibromobutane bromide without carcinogenic toxicity were used as raw materials. Brominated polysulfone (BPSF) was obtained by introducing exchangeable bromine atoms onto polysulfone molecules through the alkylation reaction. Subsequently, a kind of pyrenesulfonic type side chain sulfonated polysulfone(PS-TS) was obtained by locating sulfonic group far away from main chain of polymers via nucleophilic substitution reaction with 8-hydroxy-1,3,6-pyrene trisulfonic acid sodium (TS) as the nucleophilic reagent. The PS-TS cation exchange membrane was prepared by solution casting method. A series of PS-TS-n membranes with different bonding amounts of sulfonic acid group, PS-TS-1(0.79 mmo/g), PS-TS-2(1.01 mmo/g) and PS-TS-3(1.28 mmo/g) was prepared by controlling the flnucleophilic substitution reaction time. The result show that PS-TS proton exchange membranes keep outstanding size stability at high water sorption because they could form obvious micro-phase separation structure by locating the hydrophilic region far from the hydrophobic region. With the bonding amount of sulfonic acid group increases, the degree of micro-phase strengthens. The swelling ratio of PS-TS-3 cation exchange membrane, whose bonding amount of sulfonic group is 1.32 mmol/g, is only 22.9% and 51.3% at room temperature and 85 ℃, respectively. The corresponding proton conductivities are up to 0.088 S/cm and 0.149 S/cm, respectively. The size stability is better than that of commercialized Nafion115 at the same condition. It is expected to be used in practical applications for fuel cells.

Key words: Polysulfone, Pyrenesulfonic type, Dimensional stability, Water uptake, Methanol permeability