The synthesis of branched chain polyvinyl acetates

A range of branched polymers has been prepared by condensing polyvinyl acetate chains containing a terminal carboxyl group, on to a radioactive, partially alcoholyzed backbone of polyvinyl acetate. The important advantage of this process over normal grafting techniques is that the branches may be fractionated and characterized prior to attachment to the main chain. The viscosity behavior of these molecules in dilute solution has been studied, and, although the degree of coiling appears to be similar to that for corresponding linear molecules of the same molecular weight, they do show abnormally high Huggins' constants. Tetrahydrofuran was used as a solvent for the viscosity measurements in order that unreacted hydroxyl groups would not affect the value of the limiting viscosity number and slope constants. Before other solution properties are examined, the polymers will be acetylated in solution with ketene.