POLYMERIZATION OF METHYL-METHACRYLATE CATALYZED BY BENZOYL PEROXIDE AND CARBON-BLACK SURFACE

Carbon black acts as an inhibitor in the initial stage of the bulk polymerization of methyl methacrylate (MMA) even below room temperature in the presence of benzoyl peroxide (Bz2O2) or sym-substituted Bz2O2, and then as an accelerator in the later stage of the polymerization. The polymerization in the presence of furnace black is further accelerated by introducing electron-attracting groups on the Bz202. The black treated with 2, 2'-azobisisobutyronitrile and then with diazomethane in order to deactivate oxygen-containing groups on the surface gives no induction period and the same order of an acceleration as untreated black. On the contrary, in the presence of the black previously treated with Bz2O2 in oxygen, long induction period and no acceleration are observed in Bz2O2 initiated polymerization of MMA. We conclude that the interaction of Bz2O2 with basic benzenoidal hydrocarbon on the surface of the black causes a redox decomposition of Bz2O2 to give benzoyloxy radicals and that the quinonic oxygen groups are responsible for the initial induction period observed. © 1979, The Society of Polymer Science, Japan. All rights reserved.