| Abstract: | The electroinitiated polymerization of methyl methacrylate in the presence of nitric acid has been investigated on platinum and graphite anodes. The dependence of yields and molecular weights on parameters such as current density, temperature, speed of stirring, and HNO3 concentration was determined. Under continuous electrolysis conditions a stationary state takes place and the rate of polymerization exhibits zero order with respect to monomer and a 1.5 order with respect to current. On the other hand, under postpolymerization conditions a kinetic gel effect occurs, which limits the termination rate and leads to the typical acceleration in the conversion–time curves. The effect of postpolymerization is so marked, even after supplying small amounts of charge, that the formation of long-lived radical chains is believed to be possible. In this respect HNO3 would play a fundamental role by stabilizing the growing radicals. |
