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Polymerization kinetics of methylmethacrylate by oxidation: Reduction system using cerium(IV)/lactic acid in aqueous medium

The kinetics of polymerization of methylmethacrylate initiated by cerium(IV)-lactic acid redox system was studied in an aqueous medium in the temperature range of 25-50°C. The rate of polymerization (R p ) and the rate of cerium(IV) disappearance have been measured. The effects of some water-miscible organic solvents, cationic, anionic, nonionic surfactants, and complexing agents on the rate of polymerization were investigated. The temperature dependence of the rate was studied, and the activation parameters were computed using the Arrhenius and Eyring plots. The effects of inorganic and organic solvents on polymerization were also investigated. All of them depressed both the initial rate and limiting conversion. A mechanism consistent with the experimental data, involving cerium(IV)-lactic acid complex formation, which generates free radicals, is suggested. The chain termination step of the polymerization reaction is by mutual interaction of the growing macromolecules.