A novel cross-linked quaternized composite anion-exchange membrane based on poly(epichlorohydrin) (PECH) was prepared by a facile route. First, PECH was cross-linked with 2-methylimidazole and combined with a poly(tetrafluoroethylene) (PTFE) membrane to form cross-linked PECH/PTFE (CPECH/PTFE). Then, CPECH/PTFE was quaternized by 1-methylimidazole to obtain cross-linked quaternized PECH/PTFE (CQPECH/PTFE). 1H NMR and Fourier transform infrared spectroscopic data indicated that CQPECH was successfully synthesized, and the CQPECH/PTFE membrane had a dense and homogeneous structure demonstrated by the field-emission scanning electron microscopy. The results showed that the use of 2-methylimidazole as the cross-link agent could avoid the solubility of the composite membrane in water and dimethyl sulfoxide. With an increase of 2-methylimidazole, the solubility of the PECH ionomer was decreased. M-3, one of the CQPECH/PTFE membranes, showed good thermal properties (stable below 250 °C under an N2 atmosphere), excellent mechanical strength (a tensile strength of 67.3 MPa), moderate water uptake of 45.3%, and very low swelling degree of 9.01% at 30 °C. Besides, M-3 showed a hydroxide conductivity of up to 27 mS/cm and good long-term stability in a 1 M KOH solution at 60 °C for 15 days. In addition, a single H2/O2 fuel-cell test using M-3 at 50 °C indicated a peak power density of 23 mW/cm2. These results suggested that the CQPECH/PTFE membrane had a good perspective for application in an alkaline fuel cell.
Abstract A composite anion exchange membrane of crosslinked quaternized polyepichlorohydrin/polytetrafluoroethylene (CQPECH/PTFE) had been prepared via a green and facile method, where diethylamine, 1-methylimidazole and PTFE, respectively, served as crosslinking agent, quaternization reagent and supporting material. The structure and morphology of CQPECH/PTFE membrane were investigated. Water uptake, swelling ratio, ionic exchange capacity, hydroxide conductivity, chemical stability, and thermal and mechanical properties were measured to evaluate its performance in a direct methanol alkaline fuel cell. The results indicated that CQPECH had penetrated into the pores of PTFE membrane, showing a dense and uniform structure without any pore and phase separation. Besides, CQPECH/PTFE membrane exhibited high ionic conductivity, considerable ionic exchange capacity, moderate water uptake and low swelling ratio. More importantly, the obtained composite membrane displayed high tensile strength and good chemical and thermal stability, suggesting the great potential application of CQPECH/PTFE membrane as anion exchange membrane. Graphical abstract Crosslinked quaternized polyepichlorohydrin/polytetrafluoroethylene composite anion exchange membrane had been prepared via a green and facile method, where diethylamine served as crosslinking agent. With a dense and uniform structure without any pore and phase separation, the obtained composite membrane exhibited high tensile strength and good chemical stability.
危险品化学品经营许可证（带存储）