Vibrational overtone enhancement of methyl methacrylate polymerization initiated by benzoyl peroxide decomposition

Vibrational overtone initiated polymerization has been demonstrated using intracavity photolysis of a benzoyl peroxide/methyl methacrylate mixture. Excitation of the 6νCH overtone transition of the ground electronic state of benzoyl peroxide creates radicals which subsequently begin the polymerization process. Polymer yield was monitored by comparison of the 2νCH overtone absorptions for the methyl, methylenic and olefinic CH stretches at 5946 and 6170 cm−1, respectively. Plots of polymer yield versus time demonstrate an autoacceleration of the polymerization rate commencing many hours after the photolysis period. The delay before autoacceleration depends on the duration of the photolysis.