| Abstract: | To characterize the intermediate radicals produced in the initiation of vinyl polymerization with binary systems of diacyl peroxides and tertiary amines, spin trapping technique was applied by using 2-methyl-2-nitrosopropane ( 8 ) as a spin trapping reagent. In the reactions of N,N-dimethylaniline ( 2a ) and N-N-diethylaniline ( 2b ) with benzoyl peroxide ( 1a ), N-methylanilinomethyl ( 7 ) and N-ethylanilino-1-ethyl radicals ( 16 ), respectively, were trapped, contrary to benzoyloxyl ( 4a ) and phenyl radicals which were not trapped. This was explained by assuming that benzoyloxyl radicals ( 4a ) react faster with 2a or 2b to give the radicals 7 and 16 , than being trapped with 8 . From this, 4a and 7 or 16 were concluded to be the initiating radicals in these systems. In the reaction of lauroyl peroxide ( 1b ) with 2a or 2b , however, undecyl radicals were trapped together with the radicals 7 or 16 . In the case of N-ethyl-N-methylaniline ( 2c ) both, N-ethylanilinomethyl ( 18 ) and N-methylanilino-1-ethyl radicals ( 20 ), were trapped. Further, it was found that in the reaction of 1a with poly(p-dimethylaminostyrene), both poly{1-[4-(N-methyl-N-methylylamino)phenyl]ethylene} ( 22 ) and phenyl radicals were trapped, contrary to the reaction of 1a with 2a . |
