Long-side chains functionalized cross-linked sulfonated poly (ether ketone sulfone)s as proton exchange membranes

In this study, sulfonated poly (ether ketone sulfone)s polymers with long sulfonic acid alkyl side chains and amino groups were prepared by free radical and polycondensation reaction. Poly (ether ketone)s with carboxyl groups were used for macromolecule crosslinking agent to prepare cross-linked membranes by amidation reaction. This series of membranes were characterized by FT-IR and 1H NMR. Meanwhile, cross-linked composite membranes possessed excellent mechanical properties, methanol resistance performance and thermal stability. The highest proton conductivity of 0.096 S cm−1 was observed for APD-3/CP at 80 °C. The range of methanol permeation coefficients for the prepared membranes (2.89 × 10−7cm2s−1—4.95 × 10−7cm2s−1) was far lower as compared to that of Nafion 117 (24.1 × 10−7cm2s−1). The results of morphology, swelling ratio and proton conductivity showed that the hydrophilic-hydrophobic phase separation structure effectively improved the properties of the membrane namely water uptake, dimensional stability and proton conductivity. Long-side chains functionalized cross-linked sulfonated poly (ether ketone sulfone)s proton exchange membranes had good candidate for application in fuel cells.