Synthesis and Characterization of Stable Anion Exchange Membranes: The Addition of Electron-withdrawing Group

Abstract

Anion exchange membranes (AEM) based on poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) were used as polymer electrolyte membrane for fuel cell applications. The membranes were prepared via bromination, quaternization and nitration reactions and their fuel cell-related properties (water uptake, ion exchange capacity, ionic conductivity) were determined. Also, the structures and thermal properties were studied with Fourier transform infrared spectroscopy (FTIR), Size exclusion chromatography (SEC) and Differential scanning calorimetry (DSC). Nitration of quaternized PPO (Q-PPO) leaded to a decrease in water uptake and ion exchange capacity of the AEM. However, Q-PPO membrane treated with nitration reaction (NO2-Q-PPO) exhibited a significant alkaline stability compared to quaternized PPO (Q-PPO). The results indicated that the addition of electron-withdrawing group, such as nitro, into the structure in order to improve in alkaline stability is a promising new route for preparation alkaline stable AEM membranes.