Preparation of Raspberry-like Poly(methyl methacrylate) Particles by Seeded Dispersion Polymerization

The facile preparation of nonspherical raspberry-like poly(methyl methacrylate) (PMMA) particles by seeded dispersion polymerization of methyl methacrylate (MMA) onmicron-sized PMMA seed particles was described. Various polymerization parameters influencing the particle morphology, as well as the polymerization kinetic and morphological stability, were investigated in detail. It was found that the following polymerization conditions were necessary to prepare this kind of nonspherical particles: a relatively low temperature, an appropriate ratio of seed/MMA, an initiator with a relatively low decomposition rate, and a relatively low initiator concentration. These particles showed very good morphological stability at room temperature, but they changed to the spherical ones when heat treated at 60 degrees C in methanol solution of MMA. The experimental results suggest that the prepared PMMA particles were kinetically favored and the localized polymerization of the MMA monomer on PMMA seed particle surface was responsible for the formation of the raspberry-like particles. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 120: 501-508, 2011