Synthesis and Characterization of Polybenzimidazole/α-Zirconium Phosphate Composites as Proton Exchange Membrane

To improve the high-temperature performance of proton exchange membranes, the polybenzimidazole (PBI)/alpha-zirconium phosphate (alpha-Zr(HPO4)(2)center dot nH(2)O, alpha-ZrP) proton exchange composite membranes were prepared in this study. PBI polymer containing a large amount of ether units has been synthesized from 3,30-diaminobenzidine (DAB) and 4,40-oxybis (benzoic acid) by a direct polycondensation in polyphosphoric acid. The polymer exhibited a good solubility in most polar solvents. Inorganic proton conductor alpha-ZrP nanoparticles have been obtained using a synthesis route involving separate nucleation and aging steps (SNAS). The effects of alpha-ZrP doping content on the composite membrane performance were investigated. It was found that the introduction of ZrP improved the thermal stability of the composite membranes. The PBI/ZrP composite membranes exhibited excellent mechanical strength. The composite membrane with 10 wt% ZrP showed the highest proton conductivity of 0.192 S cm(-1) at 160 degrees C under anhydrous condition. The proton conducting mechanism of the PBI/ZrP composite membranes was proposed to explain the proton transport phenomena. The experimental results suggested that the PBI/ZrP composite membranes may be a promising polymer electrolyte used in high temperature proton exchange membrane fuel cells (HT-PEMFCs) under anhydrous condition. (C) 2016 Society of Plastics Engineers