Rearrangement of the polymer structure in the presence of high molecular weight additives

The solubility, diffusion, and washing-out of four new sterically hindered amines was studied in polypropylene. It was shown that dissolution induces a strong change in polymer structure: the additives solubility at 100 degrees C passes through a maximum during time and increases with additive molecular weight. The diffusion coefficients of the additives also depend on time. The stabilizers leak from the polymer in heptane and the residual concentration remaining in the polymer depends on the additive molecular weight.