Kinetics and mechanism of emulsion copolymerization. IV. Kinetic modeling of emulsion copolymerization of styrene and methyl methacrylate

Based on the micellar nucleation theory, a mathematical kinetic model for an unseeded emulsion copolymerization system is developed, where the radicals with and without electric charge are discriminated from each other in view of the role in the particle nucleation process. In order to demonstrate the validity and utility of this kinetic model, the experiments of the unseeded emulsion copolymerization of styrene (ST) and methyl methacrylate (MMA) are carried out varying the initial initiator (potassium persulfate) and emulsifier (sodium lauryl sulfate) concentrations and the monomer composition in the initial monomer feed, and various kinetic features observed are compared with the model predictions. It is concluded from this comparison that in this system, almost all the polymer particles are generated by the charged radicals stemming from the initiator, and further that this mathematical kinetic model can provide a satisfactory explanation of the various kinetic features observed.