Synthesis and characterization of aniline‐containing anion‐conducting polymer electrolyte membranes by radiation‐induced graft polymerization

ABSTRACTPoly(trimethylaminostyrene hydroxide)‐grafted poly(ethylene‐co‐tetrafluoroethylene) (ETFE) membranes (An‐AEM/OH) were prepared by the radiation‐induced graft polymerization of N,N‐dimethylaminostyrene and successive quaternization and anion‐exchange reactions. An‐AEM/OH with an ion‐exchange capacity (IEC) of 1.59 mmol/g exhibited a conductivity of 74 mS/cm (60°C) and a water uptake of 66%. These values were lower than those of poly(vinylbenzyltrimethylammonium hydroxide)‐grafted ETFE (BA‐AEM/OH) with a similar IEC. The conductivities of An‐AEM/OH with IECs = 0.67 mmol/g and 1.59 mmol/g decreased to 40% and 46% of the initial values after a week, while the membranes maintained their shape even after immersion in 1 M KOH at 80°C for 3 weeks. An‐AEM/OH exhibited higher chemical stability than BA‐AEM/OH. The main degradation route is confirmed to be the nucleophilic attack of hydroxide ions on the methyl groups of the aniline nitrogen from the results of thermal and chemical stability. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46886.