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The synthesis and properties of novel cross-linked composite sulfonated poly (aryl ether ketone sulfone) containing multiple sulfonic side chains as proton exchange membranes were

investigated. The multiple side-chain membranes were prepared by direct polycondensation and simple free radical reaction. The cross-linked composite membranes were prepared by solvent coating method. The prepared membranes showed lower water absorption and swelling ratio than that of Nafion 117. The S-Am-2.0/C exhibited the highest proton conductivity of 0.135 S cm-1 at 80 oC, while its swelling ratio was only 3.59 % at the same temperature. Much lower methanol permeability coefficients in the range of 3.11×10-8 cm2 s-1–7.25×10-7 cm2 s-1 compared to Nafion 117 (2.29×10-6 cm2 s-1) were also observed for the prepared membranes. Moreover, the S-Am-2.0/C exhibited higher peak power density (121.09 mW cm-2) than that of main-chain type C-SPAEKS membrane (66.65 mW cm-2). The results indicate that the cross-linked composite membranes are good candidate for fuel cells.