Solution and bulk properties of branched polyvinyl acetates part III--Intrinsic viscosity and light scattering measurements

Abstract

Light scattering and intrinsic viscosity measurements have been made on three different series of vinyl acetate polymers, one linear and two branched. One of the branched series was obtained by fractionation of a high conversion polymer, the other by a graft polymerization under conditions that allowed structural characterization of the resultant comb-shaped polymers. These data show that the ratio of the mean-square radii of gyration of branched and linear polymers of the same molecular weight is greater in good solvents than the ratio calculated tl eoretically for a theta solvent. The ratio of the second virial coefficients of the comb-shaped branched and linear polymers of the same molecular weight is equal within experimental error to the ratio of the intrinsic viscosities. The ratio of the intrinsic viscosities of branched and linear polymers is greater in a good solvent than in a theta solvent, in support of inferences from the behavior of the radius of gyration. A theoretical expression for the ratio of the intrinsic viscosities in a poor solvent is obeyed more nearly in a good solvent than in a theta solvent.