Poly(methyl methacrylate)/polystyrene composite latex particles with a novel core/shell morphology

A study was conducted to demonstrate the synthesis of poly(methyl methacrylate)/polystyrene (PMMA/PS) composite latex particles that had a novel core and shell morphology. The particles were synthesized through seeded soap-free emulsion polymerization of styrene in the presence of PMMA particles using a water-soluble nonionic azo-initiator, 2,20-azobis[2-methyl-N-(2- hydroxyethyl)propionamide]. The polymerization kinetics and the morphology of the resulting PMMA and PS particles were investigated and compared with the case using the ionic potassium persulfate (KPS) initiator. All polymerizations were performed in a 300 mL roundbottom separated flask equipped with a nitrogen inlet, a sampling syringe, and a mechanical agitator. The latex particles sampled during the polymerization were also analyzed using a particle size analyzer.