The chemical crosslinking effect of polybenzimidazole/polyvinyl alcohol blend membranes for proton exchange membrane fuel cells: An experimental study

In this survey, the different weight ratios of polybenzimidazole (PBI)/polyvinyl alcohol (PVA) blend polymer membranes were produced using the solution-casting method. The crosslinking agents of phosphoric acid (PA) and glutaraldehyde (GA) were studied separately to prevent the PVA water solubility in the PBI/PVA blend membrane structure. The GA crosslinking (24 h) successfully prevented membrane solubility, reducing it to below 1%. The chemically crosslinked blend membrane (Cr-PBI/PVA-9:1) has the highest proton conductivity result which is 0.209 S cm(-1) at 80 degrees C and it has excellent oxidative stability since the membrane only lost 4% of its weight in a Fenton agent after 96 h. The Cr-PBI/PVA-9:1 also has higher proton conductivity than the commercial PBI membrane (0.122 S cm(-1) at 80 degrees C). The glass transition temperature of the synthesized Cr-PBI/PVA-9:1 blend membrane is greater than the synthesized PBI membrane (390 degrees C). The current density and power density measured at 0.6 V for the synthesized Cr-PBI/PVA-9:1 membrane were found to be 504 mA cm(-2)and 251 mW cm(-2). This work sheds light on the potential use of PVA in PEMFC applications by mixing PVA with a high-temperature polymer like PBI and crosslinking the membrane with a prepared GA crosslinking agent.