Use of cobalt complexes as activators in emulsion copolymerization of butadiene and styrene

Cobalt complex compounds exhibited varying degrees of activation and retardation in butadiene‐styrene‐soap emulsion polymerization systems at 20–50°C. An accompanying effect was the wasting of modifier, particularly by large concentrations of activator. The most active complexes for use with dodecyl mercaptan were those in which the cobalt was coordinated with two or more negative groups other than thiocyanate, and in which the neutral coordinated groups were not ethylenediamine.