In this work the bisphenol-A-polysulfone (PSF) was sulfonated using trimethyl silyl chlorosulfonate [(CH3)3SiSO3Cl] as a mild sulfonating agent in a homogeneous solution of dichloroetane. The sulfonation reaction was confirmed by acid-base titration and FTIR-spectroscopy analysis. The hybrid membranes were obtained by casting the sulfonated bisphenol-A-polysulfone (SPSF) and precipitated silica Tixosil® 333 solutions in N-N-dimethylacetamide. Cross-linking in the hybrid membranes was obtained by irradiation, with doses ranging from 5 to 30 kGy using gamma ray from a 60Co source. The water uptake and the swelling of the membranes were estimated by measuring the change in weight between dry and wet conditions. The conductivity of the membranes in acid form was measured with the ac impedance technique using a PGSTAT30 frequency response analyzer. The hybrid cross-linked membranes have conductivity close to 10-1 S.cm-1 at 100% RH and 80 °C. Electrochemical performances, thermo-mechanical stability and low cost make this cross-linked SPSF hybrid membrane an attractive material for fuel cells using a proton exchange membrane.
Hybrid membrane; proton conductivity; gamma ray irradiation; cross-linked
