Radiation aging and degradation mechanism of polymer insulation for electric cables

摘要

The degradation mechanism of insulation materials for electric cables was studied on the point of the relation of radiation-induced oxidation to gel fraction and tensile properties. Flame retardant crosslinked polyethylene (FR-XLPE) and specialheat resistant polyvinyl chloride (SH-PVC) were investigated by volume resistivity, gel fraction, and tensile property. Furthermore, the oxidation profile by Electron Probe Microanalysis (EPMA) Ultra Micro Hardness Measurement and Scanning AcousticMicroscopy (SAM) after 60 Co gamma-ray irradiation in various oxidative conditions were investigated.As a result of the experiments, it was confirmed that the electric property is changed by radiation oxidation, gel fraction corresponds well to the proportion of oxidation layer, and a surface oxidation layer induces the fracture of specimens during thetensile test, as a notch effect.