Influence of an external electric field on the rupture force of decane, 4-decanone, and dicumyl peroxide molecules: Computational insight

Abstract

To clarify the degradation of the electrical insulation ability of polymeric materials at the molecular level, the effects of an external electric field on the rupture of molecules were evaluated using quantum chemical calculations. Two molecular models were evaluated with the aim of elucidating the physicochemical background of realistic insulation deterioration factors, namely, the effect of oxidation and impurities. The first model was used to evaluate the effect of oxidative degradation of alkane molecules on the C–C bond; maximum rupture force of the C–C bonds of decane and 4-decanone were compared, and it was found to decrease by approximately 13.8 %. It was also clarified that the maximum rupture force changes depending on the applied direction of the external electric field. The second model was used to examine the effect of an external electric field on the decomposition of dicumyl peroxide, which is a cross-linking agent for cross-linked polyethylene. In the decomposition process of dicumyl peroxide, the rupture of cumyl alcohol was found to be strongly influenced by an external electric field. Because the decomposition of cumyl alcohol involves dehydration, it is likely to induce the initiation and propagation of water trees in polyethylene. Therefore, it is important to remove the cumyl alcohol before applying a high voltage.