Polymerization of Vinyl Monomer Initiated by TiCl₃ and Oxygen

Abstract

Vinyl monomer(MMA) began to polymerize by TiCl₃ in water containing oxygen after a certain induction period. The polymerization did not occur in water free from oxygen. The yield of polymer increased with increasing oxygen content(Fig.1). The concentration of TiCl₃decreased rapidly by the reaction of it with dissolved oxygen, and the mole ratio of reacted TiCl₃ to oxygen was 4(Fig.3) in the absence of MMA. In the presence of MMA, how ever, the mole ratio was about 2(Figs.4, 5), and polymerization occurred after oxygen was almost consumed. These results suggest that the reaction of TiCl₃ with oxygen proceeds by radical process, and the reaction mechanism during the induction period was considered. Some of oxygen changed to peroxides during the induction perio d(Table 1), and it was assumed that the redox reaction of these peroxides with TiCl₃ initiated the polymerization.