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A series of sulfonated poly(aryl sulfide sulfone)s (PASS-xx) with different degrees of sulfonation were prepared by the nucleophilic aromatic substitution reaction using bis(4-fluoro-3-sulfonated phenyl)-(3-sulfonated phenyl)phosphine oxide trisodium salt, bis(4-fluorophenyl)sulfone and 4,4'-thiobis(benzenethiol) as starting materials. The intrinsic viscosities of these polymers were between 0.69 to 0.85 dL/g. All the sulfonated polymers had good solubility and film formation ability in some solvents. They could afford flexible proton exchange membranes by solution-casting. Their chemical structures and some properties, including water absorption, dimensional stability, mechanical properties, thermal and chemical oxidation stabilities and proton conductivity, were investigated. The representative sulfonated poly(aryl sulfide sulfone) with 30% degree of sulfonation (PASS-30) showed good combination properties: the water absorption was 49.0%, the swell ratio was just 15.8% and the proton conductivity was 178 mS·cm^-1. Moreover, PASS-30 also has excellent thermal and chemical oxidative stabilities and mechanical properties. Considering the facile synthetic route and the overall copolymer properties, the resulting sulfonated poly(aryl sulfide sulfone)s are promising as proton exchange membranes for fuel cell application.

Proton exchange membrane; Sulfonated poly(aryl sulfide sulfone)s; Water uptake; Swelling ratio