Synthesis of large-sized monodisperse polystyrene microspheres by dispersion polymerization with dropwise monomer feeding procedure

Highly monodisperse polystyrene (PS) microspheres in the size range of 3.75-7.09 μm were synthesized by dispersion polymerization with dropwise monomer feeding procedure. The morphology, size, and particle size distribution (PSD) of the PS microspheres obtained by different monomer feeding modes, including batch polymerization and various feeding rates, were investigated. The PSD of particles showed a close dependence on feeding rate. The PS microspheres with low coefficient of variation (CV) values all less than 4.8% obtained by the optimum feeding rates revealed better uniformity than those by batch polymerization (CV values all more than 8.2%). According to the time courses of monomer conversion and particle numbers, the effects of monomer feeding modes on the polymerization reaction of the large-sized PS microspheres were clarified. It is found that the dropwise monomer feeding procedure is promising for the synthesis of large-sized monodisperse PS particles in 3.75-7.09 μm.