The alkali stability of radiation-grafted anion-exchange membranes containing pendent 1-benzyl-2,3-dimethylimidazolium head-groups

Radiation-grafted anion-exchange membranes (AEM) containing pendent benzyltrimethylammonium, 1-benzyl-3-methylimidazolium and 1-benzyl-2,3-dimethylimidazolium functional head-groups were synthesised with ion-exchange capacities in the range 1.7-1.9 meq g super(-1). The ionic conductivities of the AEMs were also comparable (24.5 plus or minus 1.8 mS cm super(-1) at 50 degree C). The alkali stability (in aqueous potassium hydroxide (1 mol dm super(-3)) at 60 degree C) of the 1-benzyl-2,3-dimethylimidazolium head-groups was superior to the 1-benzyl-3-methylimidazolium but inferior to the benzyltrimethylammonium benchmark head-groups. Radiation-grafted AEMs containing pendent 1-benzyl-2,3-dimethylimidazolium head-groups are not suitable for application in electrochemical devices containing highly alkaline environments.