Determination of molecular weight and size distribution and branching characteristics of PVAc by means of size exclusion chromatography/multi-angle laser light scattering (SEC/MALLS)

SEC/MALLS has been applied for the determination of molecular weight and size distributions and to quantify branching in polyvinyl acetate (PVAc). Linear and branched samples obtained by solution and bulk polymerization were analyzed. The molecular weight distribution of the branched polymer was broader and the mean square radius was found to be smaller, 38.8 nm (with molecular weight of 770 000), than for the linear polymer, 42.3 nm (with molecular weight of 740 000). Branching characteristics could be determined by using Zimm and Stockmayer equations. It has been found that the number of branches for the branched sample increases from about 1 to 9, per molecule, with increasing molecular weight.