高温領域における低密度ポリエチレンの高電界特性と物性

II. カルボニル基の形態と結晶性による検討

抄録

The authors discussed the effects of types of carbonyl groups on high-field conduction and breakdown for low density polyethylene (LDPE) films. LDPE films with carbonyl groups of terminal ester type were found to have a lower high-field current at 90°C than LDPE films with carbonyl groups in main chain. The do breakdown strength at 90°C of the former was slightly higher than that of the latter, but the impulse breakdown strength did not depend on the types of carbonyl groups. The breakdown strength depended on film density and melting point. Since the size of crystalline region in the latter was suggested to be larger than that in the former from the DSC measurement, it is concluded that the high-field conduction in LDPE films is explained by the conduction process through the sites in the interface region between crystalline and amorphous parts. However, the breakdown process in LDPE was not related to the type of carbonyl groups probably because the breakdown in LDPE is concerned with a filamentary thermal breakdown in a weak point in the amorphous region.