Photoluminescence in polymeric insulating materials (low density polyethylene and polypropylene) induced by ultraviolet photons

For the polymeric insulating materials such as polypropylene (PP) and low density polyethylene (LDPE), the surface oxidization and chain scission that deteriorate the insulation performance are induced by the irradiation of the ultraviolet photons. Photochemical reactions are responsible for such oxidization and bond scission. In this research, photochemical reactions in the polymers are examined by analyzing photoluminescence (PL) spectra. However, it is the case that the luminescence of the polymer becomes a complicated phenomenon accompanied with several kinds of mechanisms even when the clearest excitation means of the laser irradiation is used. Therefore, luminescence due to the oxidation that relates essentially to the degradation of PP or LDPE is examined in this research by comparing luminescence spectrum induced by the irradiation in vacuum and the one induced in oxygen