Study of fast processes in oxidized polypropylene in the presence of pyrene

Abstract

The study of oxidized polypropylene, undoped and doped with pyrene was carried out with the main aim of investigating energy and charge transfer in these systems. The transient absorption spectrum of trapped electrons was not detected in the case of oxidized polypropylene because of electron scavenging by products of polymer oxidation (peroxides and carbonyl groups). In doped oxidized polypropylene, transient absorption bands due to pyrene radical anions (λ max = 500 nm) and cations (λ max = 450 nm) were observed. The yields of these bands in this system were lower than in non-oxidized polypropylene. The ratio of absorption at 450 nm and 500 nm was different in these polymer matrices, too Relatively less pyrene radical-anions were generated in oxidized system. The pulse irradiated pyrene-oxidized polypropylene system generated much weaker emission attributed to pyrene monomer fluorescence than in non-oxidized polymer. All these results suggested that oxidized polypropylene matrix interacted with primary charges hence, pyrene radical ions yield and solute ion-recombination leading to excited state formation was limited.