Mechanisms on inhibition of polyethylene electrical tree aging: a theoretical study.

A theoretical investigation is completed on inhibition mechanism of polyethylene electrical tree aging. Foremost it elucidates that it is one of the important factors for inhibiting initiation and propagation of polyethylene electrical tree through keto-enol tautomerism of acetophenone and its analogues. Geometries of the keto tautomer and the enol tautomer of acetophenone and its analogues, and its transition states are optimized at the B3LYP/6-311+G(d,p) level, the harmonic vibration frequencies of the equilibrium geometries are calculated at the same level. The minimum energy path (MEP) is obtained by the intrinsic reaction coordinate (IRC) theory at the same level. The calculated results show that the energy barriers of keto-enol tautomerism of acetophenone and its analogues are smaller than the average C-C bond energy of polyethylene, the acetophenone and its analogues adulterated in polyethylene composites can improve the strength of alternate current puncture that PE can endure as well as inhibit polyethylene electrical tree from initiation and propagation.