Molecular Dynamics Simulation and Density-Functional Analysis on Suppression Effect of Electrical Tree in Antioxidant-added Polyethylene

This paper describes the suppression effect of electrical tree in antioxidant-added polyethylene (PE) using molecular dynamics (MD) simulation and density-functional theory (DFT) approaches. Although it has been reported experimentally so far, it has not been theoretically confirmed. Firstly, we designed the molecular structure of polyethylene to which antioxidants are added. After that, we extracted a part of molecules to analyze the energy levels, the molecular orbitals and the electrostatic potential distribution in the case where PE and antioxidant coexist. In addition, an external electric field was applied assuming the generation of electrical tree. The results show that trapping sites of electrons are formed when the molecular chains of PE intersect in proximity. Moreover, the results also show that the antioxidant-added PE is greatly affected by the magnitude and direction of the external electric field.