Kinetics and mechanism of emulsifier-free emulsion polymerization. III. Styrene/nonionic comonomer (2-hydroxyethyl methacrylate) system

[[abstract]]©1990 Wiley - The emulsifier-free emulsion polymerizations of styrene in the presence of about 0.33-2.7% (relative to styrene) of the water soluble comonomer, 2-hydroxyethyl methacrylate (HEMA), and of the initiator, potassium persulfate (KPS), were carried out. It was found that KPS plays a predominant role in the particle nucleation process, since the number density of polymer particles (Np) was dependent on the 0.97-power of [KPS]. The nucleation ability of HEMA was weak, since Np was dependent only on the 0.17-power of [HEMA]. The particle nucleation stage ceased quite early before 1% conversion, leading to nearly monodispersed polymer particles. The nucleation is suggested to be via the homogeneous nucleation mechanism.[[department]]化學工程學