Preparation of monodisperse polystyrene particles by radiation-induced dispersion polymerization using waterborne polyurethane as a stabilizer

Novel waterborne polyester polyurethane (WPU) was synthesized and firstly applied to dispersion polymerization of styrene (PSt). Monodisperse PSt particles were successfully prepared by radiation-induced dispersion polymerization, after dispersed in ethanol–water medium and stabilized by WPU at room temperature. The conversion–time curve was investigated, and the grafting reaction between WPU and PSt was investigated via FT-IR, XPS and 1H NMR spectrum. Furthermore, the grafting efficiency of WPU (GWPU, ratio of grafted WPU versus the total content of WPU in the system) was calculated via 1H NMR spectrum. It shows when vinyl groups are attached to WPU molecules, the diameter of PSt particles decrease.