Effect of water on the induction period of the polymerization of methyl methacrylate

Abstract

The effect of water in monomer on the length of the induction period of the polymeri-zation of methyl methacrylate was investigated for varying concentrations of water, catalyst, and inhibitor. For the benzoyl peroxide catalyzed polymerization, t he induction period is markedly shortened by small quantities of water in the monomer. It is inversely proportional to the water concentration and directly proportional to the hydroquinone content. In the absence of inhibi tor it is inversely proportional to the square root of the catalyst concentration. This acceleration effect is caused by the more rapid decomposition of benzoyl peroxide in water-containing monomer, with a subsequent slight in crease in free radical concentration , which is sufficient to shorten t he induction period. Water in the monomer does not alt er appreciably the reaction rate after the induction period .