Preparation of Sulfonated Crosslinked Poly(2,6-dimethyl-1,4-phenylene oxide) Membranes for Direct Methanol Fuel Cells by Using Electron Beam Irradiation

Abstract

Sulfonated crosslinked poly(2,6-dimethyl-1,4-pheylene oxide) (PPO) (CPPO) membranes for direct methanol fuel cells (DMFC) applications were prepared by using electron beam radiation. PPO membranes were crosslinked by electron beam irradiation under various conditions. The CPPO mebranes were sulfonated with chlorosulfuric acid (CSA) as a sulfonation agent. A polymer solution containing PPO in chloroform was filtered through a 0.45 μm PTFE syringe filter and then casted on a well-cleaned glass plate. The films were dried at room temperature for 1 hour and then dried in a vacuum oven at 50°C for 2 hours. The prepared films were put into a chamber filled with argon gas for electron beam irradiation. Proton conductivity was measured with an impedance analyzer over a frequency range of 1 Hz to 106 at room temperature and 100% relative humidity condition using a four-point probe method. The proton conductivity of the SCPPO membrane was 1.5 times higher in comparison to that of Nafion 115 for the highest sample.