Model Filled Polymers 8. Synthesis of Crosslinked Polymeric Beads by SeedPolymerization

摘要

Monodisperse crosslinked polystyrene (PS) and polymethacrylate (PMA) beads ofsizes greater than 1 micron in diameter are prepared by particle nucleation onto pre-existing polymer seeds in a multistage emulsion polymerization, in the absence of emulsifier. An adequate seed concentration, which decreases with increasing seed size, is necessary to achieve monodisperse beads. Monodisperse multicomposition beads are prepared by polymerizing styrene onto PMA seeds, but not by polymerizing methyl methacrylate onto PS seeds. Free radical capture by growing seed particles with surface polymerization may lead to the formation of asymmetric shaped particles.