Characterization of polyvinyl acetate by molecular weight determination.

The need for an absolute method to follow the changes in viscosity shown by polyvinyl acetate in various solvents, initiated a study of osmotic methods for determining molecular weights of this polymer. A Carter-Record type of cell was found less convenient than a modified form of the Van Campen osmometer. Number average molecular weights for polyvinyl acetate determined with the latter did not agree with reasonable predictions of intrinsic viscosity measurements when Carter-Record type membranes were used. Reasonable molecular weights were obtained for Gelva 15,45,150 and 360 with caustic treated membranes.[...