Kinetic Study of the Microemulsion Polymerizations of Methyl Methacrylate and n-Butylacrylate

364-374Microemulsion polymerizations of methyl methacrylate (MMA) and n-butyl acrylate (BA) have been studied, using sodium lauryl sulphate (SLS) as surfactant and potassium persulphate (KPS ) as initiator. Cetyl alcohol (CA) and octyl alcohol (OA) are used as cosurfactants (CS) in the present stud y. The rates of microemulsion polymerizations of M MA show 0. 39 and 0.44 power dependencies on [KPS] with SLS-CA and SLS-OA as surfactant-cosurfactant pairs, respectively. The rates of microemulsion polymerizations of BA show 0.33 and 0.54 power dependencies on [KPS] with SLS-CA and SLS-OA as surfactant and cosurfactant pairs in the reaction medium, respectively. The latex solutions of MMA made by microemulsion polymerization methods using SLS-OA as surfactants combination show that the particle sizes of latex solutions decre:1se with the increase of initiator concentration in the reaction medium. Whereas, the latex solutions of BA do not show any regular trend in the variation of particle sizes with the initiator concentration. The rates of microemulsion polymerizations of MMA with SLS-CA and SLS-OA as surfact-antcosurfactant combinations in the reaction medium show 0.61 and 0.60 power dependencies on total surfactants concentration, {[SLS]+[CS]}, respectively. The rates of microemulsion polymerizations of BA show 0.5H and 0.60 power dependencies on{[SLS]+[CS]} with SLS-CA and SLS-OA as surfactants combinations, respectively. The effects of monomer concentration oil microemulsion polymerizations of MMA and BA are also studied by keeping the oil phase constant, with the addition of non reactive diluent, toluene, to the reaction medium. The overall activation energies, Eoverall, for the microemulsion polymerizations of MMA and BA are evaluated in the temperature region 60-75oC. The overall activation energies 58.83 and 22.22 kJ/mol are obtained for the microemulsion polymerizations of MMA with CA and OA as cosurfactants in the reaction medium, respectively. The overall activation energies 29.12 and 47.87 kJ/mol are obtained for the microemulsion polymerizations of BA with CA and OA as cosurfactants in the reaction medium, respectively.