REARRANGEMENT OF THE POLYMER STRUCTURE IN THE PRESENCE OF HIGH-MOLECULAR-WEIGHT ADDITIVES

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