a vacuum oven to 62 30 grams of light brown solid consisting essentially of copolymer iia as defined hereinbefore benzene 500 ml was heated to reflux under nitrogen in a flask benzoyl peroxide 27 2 g was dissolved in another 500 ml of benzene and to this was added 300 ml of 1 vinylimidazole and ethylene glycol dimethacrylate 3 ml to form a solution this solution was added to the refluxing benzene and washed in with 200 more ml of benzene the resulting mix was stirred under nitrogen with refluxing for 5 hours after slight cooling and filtering the resulting mix was dried under vacuum for 16 hours at 60 u00b0 c and then dried further under vacuum at 60 u00b0 c to yield 147 8 g of a viscous liquid including vinylimidazole ethylene glycol dimethacrylate containing 3 ethylene glycol dimethacrylate moiety and having structure formula as set forth above for copolymer i with n equal to 30 except that the resin was unquaternized this liquid was admixed with ethanol 1 1 and iodomethane 90 ml 1 44 moles and stirring at room temperature was carried out for 16 hours the resulting mix was filtered and washed three times with absolute ethanol to provide a light tan powder with a skin on top the skin was removed and the powder was dried under vacuum at 60 u00b0 c for 23 hours to yield 127 1 g of light brown powder to 123 4 g of this was added 40 ml of iodomethane and 500 ml.