Preparation Of High-Temperature Proton Exchange Membranes Based On Semi-Interpenetrating Polymer Networks

To realize the tradeoff between high proton conductivity and high mechanical strength , a semi-interpenetrating polymer network (PIN) based on a sulfonated poly (aryl ether ketone) bearing unsaturated double bonds (Allyl-SPAEK) and an arylether-type polybenzimidazole (PBI) has been fabricated for high-temperature proton exchange membranes in fuel cells. Based on the molecular design and syntheses of Allyl-SPAEK and PBI, a new IPN system composed of covalent bond formed by allyl groups and strong acidbase interactions formed by imidazole-sulfonic acid groups was obtained through a process of solution casting and UV irradiation. The results showed that the PBI/Allyl-SPAEK membranes could have simultaneously improved proton conductivity and mechanical strength, which were much better than the pristine PBI membrane under the same phosphoric acid adsorption level and test conditions. With a phosphoric acid adsorption level of ca.13.0, the maximum tensile strength of one PBI/Allyl-SPAEK membrane was 12.1 MPa, and its young' s modulus reached 131.5 MPa, which was twice of the pristine PBI membrane. At 200 degrees C, the proton conductivities of two membranes reached above 200 mS/cm , which was 38% higher than that of the pristine PBI membrane.