Emulsifier-free, organotellurium-mediated living radical emulsion polymerization of Styrene: Initial stage of polymerization

Behavior of the particle formation based on self-assembling in emulsifier-free, organotellurium-mediated living radical emulsion polymerization (emulsion TERP) of styrene was studied from the molecular weight distributions (MWDs) of polystyrene (PS) formed in an initial stage of the polymerization at different temperatures from 50 degrees C to 70 degrees C. As the polymerization temperature was decreased, the larger number of poly(methacrylic acid) (PMAA: degree of polymerization, 30)-methyltellanyl (TeMe) (PMAA(30)-TeMe) participated in the polymerization, resulting in amphiphilic PMAA(30)-b-PS-TeMe oligomers. Almost all control agents were consumed and a self-assembly nucleation occurred in the initial stage of the polymerization at 50 degrees C, which lead to depress of particle formation of a homogeneous nucleation. The consumption rate of PMAA(30)-TeMe affected directly the particle formation. From these results, it is concluded that it is important for the emulsion TERP of styrene with excellent control/livingness that the self-assembly nucleation proceeds without the homogeneous nucleation in the initial stage of the polymerization. (c) 2011 Elsevier Ltd. All rights reserved.