Study of the effect of valence bond isomerizations on electrical breakdown by adding acetophenone to polyethylene as voltage stabilizers

A theoretical investigation on the mechanisms of acetophenone added to polyethylene as voltage stabilizers is accomplished at the atomic and molecular levels. The five reaction pathways of valence bond isomerization of acetophenone have been elucidated. The electronic structures at the ground states and lowest triplet states of acetophenone and its valence bond isomers were calculated at the B3LYP/6-311+G(d,p) level. The HOMO-LUMO energy gaps, ionization potentials, and electron affinities at the ground states of studied molecules were obtained at the same level. The theoretical results are in good agreement with the available experimental findings. Our calculations indicate that the valence bond isomerization forming the Hückel structure is the major pathway, and the other valence bond isomerizations that yield Dewar, Ladenburg, and Bicyclopropylene acetophenones are minor pathways. Based on these results, several interesting voltage stabilizers have been designed.