Emulsion copolymerization of methyl methacrylate and ethyl acrylate. 3. Kinetic studies

The emulsion copolymerization of methyl methacrylate and ethyl acrylate initiated by ammonium persulfate in the presence of both anionic and nonionic emulsifiers was investigated. The dependence of conductance on conversion is described by a curve with a minimum at conversion about 30%. The dependence of the number of polymer particles on conversion is described by a curve with a maximum at 50% conversion. The particle size increases with increasing conversion especially at the low conversion range. A sharp increase in conductance with conversion after 40 or 50% conversion is probably due to both the lower affinity of anionic emulsifier to the polymer particle surface compared to that for the nonionic emulsifier and to the decrease of the total polymer particle surface. Due to these phenomena the most conductive species are concentrated within the aqueous phase.