Poly(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.
ASJC Scopus subject areas
- 化学 (全般)