NONIONIC LATICES IN AQUEOUS-MEDIA .4. PREPARATION AND CHARACTERIZATION OF ELECTROSTERICALLY STABILIZED PARTICLES

The rate of conversion of styrene into polystyrene by emulsion polymerisation has been investigated in the absence and in the presence of methoxy-polyethyleneglycol methacrylate, MeOPEGMA. The effect of adding MeOPEGMA at different stages of the polymerisation was also investigated. Additions at the beginning of the polymerisation and at the early stages gave a bimodal particle size distribution whereas late additions gave small particle size, monodisperse latices which were electrosterically stabilised. The latter materials were found to be colloidally stable to the addition of high concentrations of electrolyte and to freeze-thaw conditions.