FREE-RADICALS IN IRRADIATED UNSTABILIZED POLYPROPYLENE, AS SEEN BY DIFFUSE REFLECTION-ABSORPTION SPECTROPHOTOMETRY

The introduction of UV-Vis absorption spectrophotometry to the study o f radiation chemistry of polymers has opened the possibility to invest igate even very opaque samples. The virgin powder polypropylene, as ob tained from the industrial production line, shows after irradiation un stable products of radiolysis. Until now they were investigated mainly by EPR method. Optical absorption spectra (by diffuse reflection spec trophotometry) contribute to better identification and study of change s in time, temperature and diffusion of reactive gases. Studying the f ormation of stable compounds, which do not produce EPR signal, we are able to examine these species on the basis of their electronic spectra . The most important results concern the peroxides in irradiated polyp ropylene.