The influence of oxidation on thermally stimulated currents from trapped carriers in high density polyethylene

Thermally stimulated currents (TSC) were measured from oxidized and unoxidized high-density polyethylene with prior X-ray irradiation. Six TSC peaks due to trapped carriers were observed in the unoxidized samples. Slight oxidation introduced a new peak around 280 K, which was ascribed to unstable intermediates in the oxidation process. Further oxidation reduced the TSC below 340 K and enhanced the TSC peak around 360 K ascribed to stable oxidation products such as carbonyl groups. The TSC without X-ray irradiation were also reduced by oxidation. These reductions are considered to be closely related to the introduction of deep traps responsible for the TSC peak around 360 K. (author)