Polymerization of Vinyl Acetate by Metal Alkyls

III. Polymerization of Vinyl Acetate by Trialkylboron

Abstract

The polymerization initiated by triethylboron was examined. Oxygen had a remarkable promoting action on the triethylboron catalysed polymerization. And also, the polymerization was accelerated by the presence of small amounts of water and methanol. In the case using the large amount of the catalyst, the degree of polymerization was remarkably decreased. From the determination of carboxyl group containing in PVA, it was suggested that the chain transfer to the catalyst took place. The physical properties of PVA, for example, the degree of swelling, the amount of 1, 2-glycol, are similar to those of PVA obtained from the usual radical polymerization. From the above results, it seems likely that the polymerization by using triethylboron is induced by a radical mechanism.