Photopolymerization of methyl methacrylate with binary system of triphenylphosphine and benzyl bromide

• Published in: European polymer journal 1993-07, Vol.29 (7), p.971-974
• Main Authors: Bajpai, U.D.N., Otsu, T.
• Format: Article
• Language: English
• ISSN: 0014-3057; 1873-1945
• DOI: 10.1016/0014-3057(93)90294-P

The photopolymerization of methyl methacrylate (MMA) initiated by a binary system consisting of triphenylphosphine (TPP) and benzyl bromide was studied in order to compare the initiating efficiency of the binary system with that of the corresponding quaternary salt. The studies were also undertaken to discover whether the present system gives rise to a living radical polymerization. The rate of polymerization was found to rise with increases in the concentrations of monomer, TPP and benzyl bromide and also with increase in temperature; the overall energy of activation was 22.7 kJ/mol. Kinetic studies and the inhibition of polymerization by hydroquinone showed that the polymerization followed a free radical path. Since the number-average molecular weight of the resulting polymer did not increase with rising conversion, we conclude that the present system does not follow a living radical polymerization mechanism. The binary system is more effective in the photopolymerization of MMA than the corresponding quaternary salt. A plausible mechanism is given to explain the kinetic results.