4-Aminopyridine grafted sulfonated poly(arylene ether ketone sulfone) proton exchange membrane with high relative selectivity for fuel cells

A series of sulfonated poly(arylene ether ketone sulfone)s polymer having a degree of sulfonation of 80% and a carboxyl group in the side chain (C-SPAEKS) were prepared by polycondensation . The 4-aminopyridine grafted sulfonated poly(arylene ether ketone sulfone)s polymer membranes (SPPs) were prepared by amidation reaction with the carboxyl group to immobilize 4-aminopyridine on the side chain. The 1 H NMR results and Fourier transform infrared of SPP membranes demonstrated the successful grafting of the 4-aminopyridine. Proton conductivity , water absorption, swelling ratio, and thermal stability of different proportions of SPP membranes were investigated under the different conditions. With the increase of pyridine grafting content, the methanol permeability coefficient of the membrane decreased significantly from 8.17 × 10 −7 cm 2 s −1 to 8.92 × 10 −8 cm 2 s −1 at 25 °C. And, the proton conductivity and relative selectivity of the membrane were positively correlated with the grafted pyridine content. Among them, the SPP-4 membrane exhibited the highest proton conductivity of 0.088 Scm −1 at 100 °C. The relative selectivity increased from 4.73 × 10 4  S scm −3 to 9.84 × 10 4  S scm −3 .