Quantum mechanical criteria for choosing appropriate voltage stabilization additives for polyethylene

One of the major application fields for solid dielectric polymers is their use as insulating materials for power cables. Since the electrical aging of the insulating polymeric materials is one of the most important factors affecting the service lifetime of power cables, developing a model which can be used to design materials with an improved resistance to electrical degradation would be highly beneficial. We developed a model for the electrical field within the polymer material contaminated with a sharp conducting defect (a metallic needle) and defined a parameter characterizing the resistance of polymer to electrical treeing. The model was used to analyse data for the electrical degradation of polyethylene stabilized with polycyclic aromatic hydrocarbons. Based on quantum mechanically calculated electron affinities and ionisation potentials of the stabilizer molecules, we discovered that if a molecule is to be considered for voltage stabilization use it has to have a specific combination of the ionisation potential and adiabatic electron affinity. The model allows for a choice of appropriate voltage stabilizers based on theoretical calculations only and can help to facilitate any experimental study for choosing appropriate voltage stabilizer additives.