Novel Approach to Synthesis of Monodisperse Polymeric Microspheres: Heterophase Polymerization of Styrene and Methyl Methacrylate in Presence of Water-Insoluble Functional PDMSs

Abstract

Water-insoluble polydimethylsiloxanes (PDMSs) with functional organic substituents at the silicon atom are promising surface-active substances for the synthesis of monodisperse polymeric microspheres. In this regard a number of PDMS oligomers bearing different functional chain ends (amino, carboxylic and epoxy groups) were synthesized by conventional approaches. Solubility of PDMS in both the monomers (styrene (St) or methyl methacrylate (MMA)) and water as well as their surface-active properties at the water-toluene interface were investigated. Heterophase polymerization of St and MMA was carried out in the presence of functional PMDS and the resulting suspensions of polymeric microspheres were characterized using scanning electron microscopy (SEM). It was shown that the polymeric suspensions obtained have a very narrow particle size distribution and high stability in electrolyte solutions. The mechanism of the interfacial layer formation which explains the observed results is proposed.