Synthesis of Sulfonated Poly(arylene ether)s in a One-Pot Polymerization Process and Their Nafion-Blend Membranes for Proton Exchange Membrane Fuel Cell Applications

A series of sulfonated poly(arylene ether) (SPAE) was designed and successfully synthesized via one-step polycondensation reaction, then giving flexible, transparent and uniform membranes through solution casting method. The degree of sulfonation (DS) of the yielded polymers, confirmed by H-1 NMR analysis, could be controlled by adjusting the ratio of non-sulfonated to sulfonated monomers, and physicochemical as well as electrochemical properties of the resulting SPAE membranes were systematically characterized. The ion exchange capacity (IEC) value and water uptake were elevated with the increasing of sulfonation of degree without excessive swelling issue. The membranes exhibited good thermal, oxidative and dimensional stability. Among all the SPAE membranes, proton conductivity of SPAE-80 (0.232 S cm(-1)) is higher than that of Nafion 212 (0.205 S cm(-1)) at 80 degrees C under 100% relative humidity (RH). In the H-2/air single cell test, a higher power density of 93 mW cm(-2) was generated for SPAE-80 membrane doped with 10 wt% Nafion at 50 degrees C under 30% RH, whereas 89 mW cm(-2) for the pristine SPAE-80 membrane. The fuel cell durability of SPAE membrane was elevated when doped with Nafion.