THEORETICAL ASPECTS OF DEVELOPING LATEX PARTICLE MORPHOLOGY

Seeded emulsion polymerization was used to prepare composite latex particle for particle morphology studies. The polymerizations were carried out at 70-degrees-C using monodisperse polystyrene latex particles as seed and methyl methacrylate as the second stage monomer. The morphologies of the composite latex particles were investigated using transmission electron microscopy. A thermodynamic analysis based on three interfacial tensions was used to describe the free energy changes corresponding to various possible morphologies. Based on experimentally measured interfacial tensions, the relative stabilities of particle morphologies were calculated based on minimization of the free energy changes. Differences between observed and predicted particle morphology were found to be due to kinetic effects, mainly due to restricted chain mobility because of the high internal viscosity during the final stage of polymerization or solvent removal.