Abstract
Polymerization of methyl methacrylate was carried out by using peroxybenzoic acid as a polymerization initiator. The velocity of polymerization was proportional to the square root of the concentration of peroxybenzoic acid. From the velocity constant of formation of free radical from peroxybenzoic acid, the activation energy was 15.4 kcal and it was far smaller than the activation energy of benzoyl peroxide. The concentration of methyl methacrylate and the velocity of polymerization were approximately proportinal. The av. degree of polymerization was also proportional to the concentration. The reaction of decomposition of peroxybenzoic acid in methyl methacrylate for formation of free radical and initiating the polymerization was only a part of the whole decomposition reaction of peroxybenzoic acid but larger part of methyl meth-acrylate was decreased by the polymerization. Estimation of av, degree of polymerization of the polymer indicated that the reaction of polymer radical and peroxybenzoic acid caused much of chain transference and this caused the lowering of av. degree of polymerization. The activation energy of this transfer reaction was about 6.6 kcal.
