Reactions of hydroxyl radicals with polymerizable olefins

Abstract

The reactions of hydroxyl radicals with methyl acrylate, methyl methacrylate, styrene, and α-methylstyrene have been investigated by a trapping technique which uses 1,1,3,3-tetramethylisoindolin-2-yloxyl (1) as a radical scavenger. The major reaction pathway in each case was addition to the unsubstituted (tail) end of the monomer, although addition to the substituted (head) end and reaction with the double-bond substituents were also observed. Absolute rates of reaction were estimated by means of competition experiments using cyclohexane as reference substrate. The implications of the results for the structure of polymers initiated by hydroxyl radicals are discussed.