Sulfonated poly(aryl sulfide sulfone)s containing trisulfonated triphenylphosphine oxide moieties for proton exchange membrane

•Poly(aryl sulfide sulfone)s containing trisulfonated moieties were reported•The membranes showed moderate water uptake and low swelling ratio•The membranes possessed good proton conductivity and oxidative stability

A series of sulfonated poly(aryl sulfide sulfone)s containing trisulfonated triphenylphosphine oxide moieties (TS-PASS-xx) were prepared by the nucleophilic aromatic substitution reaction using bis(4-fluoro-3-sulfonatedphenyl)-(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 0.59 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 uptake, swelling ratio, proton conductivity, and thermal and chemical oxidation stabilities, were investigated. The representative sulfonated poly(aryl sulfide sulfone) with 30% degree of sulfonation (TS-PASS-30) showed good combination properties: the water uptacke was 49.1%, the swelling ratio was 15.8% and the proton conductivity was 178 mS/cm. Moreover, TS-PASS-30 also has excellent thermal and chemical oxidative stabilities.

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