Polypropylene chemiluminescence in the photooxidation post-effect

A correlation between the plasticizerchemiluminescence (CL) and the reaction of polymer chain termination during the post-effect of polypropylene oxidation under UV irradiation was observed. The CL decay kinetics corresponds to the kinetics of the peroxy radical termination reaction. Variation of the relative CL quantum yield per radical termination event, and the degree of enhancement of both radical loss and the plasticizer CL decay were determined. Features of the CL decay kinetics are indicative of a change in the peroxyl radical distribution with respect to the radical termination rate constants and the CL yields in the disproportionation events. Taking into account the modified distributions allows the CL decay kinetics observed in the PP photooxidatiion post effect to be described quantitatively.