Abstract: | Methyl methacrylate and styrene were polymerized by using 2,2′-azobis(2,4-dimethyl valeronitrile) as initiator in various solvents. When a poor solvent is used, the dependence of polymerization rate Rp on initiator concentration C] is small and can be treated by equations for the analysis of the polymerization with primary radical termination. With a good solvent, the dependence of Rp on C] is so large that such equations are not applicable. Thus, the C] dependence in a good solvent is explained qualitatively through the molecular weight dependence of rate for termination between polymer radicals, based on the excluded volume effect. |