The Effect of Carbon Tetrachloride on Radical Polymerizations of Methyl Methacrylate and Styrene

Abstract

Kinetics of radical polymerizations of methyl methacrylate (MMA) and styrene in carbon tetrachloride (CCl₄) were investigated. It was determined that the kinetic orders of MMA and styrene were 1.2 and 1.3, respectively, which were contrary to the expectation of the viscosity effect on the basis of termination reaction. It was found that the effect of CCl₄on the kinetic of the polymerization was not caused by either the primary radical termination or the degradative chain transfer. The propagation rate constant (k_p) and the termination rate constant (k_t) were determined by the rotating sector method. The kp values of both MMA and styrene changed little and there was no important role of CCl₄ in the propagation step. The kt values decreased with an increase in the CCl₄ concentration anti-proportionally to the viscosity of the system. The rate of initiation (R₁) decreased with the increase in the CCl₄ concentration and the decrease was found to make the kinetic order of monomer larger than unity.