Theoretical study on the radical reaction mechanism in the cross-linking process of polyethylene

Abstract

Theoretical investigation on the radical-initiated reactions of the polyethylene cross-linking process with the voltage stabilizer grafting is accomplished by density functional theory (DFT) calculations. At the B3LYP/6-311+G(d,p) level, the molecular properties of 22 reactions and reaction potential energy information of 18 radical-initiated reactions are obtained. The HOMO–LUMO energy gaps, ionization potentials, and electron affinities of the cross-linking agent, voltage stabilizer, antioxidant, and by-product in the polyethylene insulation composite are calculated. The results show that the by-product, cross-linking agent, and voltage stabilizer can effectively increase the electrical breakdown strength. In addition, aromatic ketone voltage stabilizer and hindered phenol antioxidants of the studied molecule can be grafted to polyethylene chain easily during the polyethylene cross-linking process, and they have excellent compatibility with polymers matrix. The investigation is expected to provide reliable information for optimizing process and for the development of the insulation material of high-voltage cable exceed 500 kV in real applications.