Cyrotyns'ka I. Quantitative parameters of photo-oxidative degradation of polyolefins.

To investigation of polymer degradation a new approach has been proposed which consists in determination of macromolecule scission and crosslink concentrations in thin consecutive layers of a polymer sample. The new method of computer aided molecular weight distribution analysis allows for comparison of degradation rates in polymers of different structures and molecular masses. The localization of products of long-term (16 to 80 weeks) photo-oxidative degradation has been studied in polypropylene samples containing (i) a stabilizing package that included hindered amine light stabilizers and a phenolic stabilizer, (ii) titanium dioxide pigment and (iii) both the pigment and the stabilizing package. The inhibiting effect of the additives has been determined quantitatively by comparing macromolecule scission and crosslinking rates with those in samples containing no stabilizer or pigment.