ABSTRACT
Irreversible chemical changes arising from degradation are localized in the polymer matrix. Heterogeneities caused by degradation were detected at molecular and supermolecular levels (18,19). Sites with highly oxygenated structures are randomly distributed in the polymer bulk and surface layers, and they are accompanied by changes in the spherulitic structure and chemocrystallization. It follows from that that the stabilizers preferentially react in the localized oxygenated sites.
