Study on the Effect of Diamond on the Dielectric Properties of Epoxy Resin Composites During Aging

With the rapid development of DC power transmission engineering, epoxy matrix composites with high dielectric strength have broad application prospects in power systems. Based on the negative electron affinity of nano-diamond, the electrical properties of epoxy resin composites after aging were studied. After drying, the epoxy resin composite (EP) and the epoxy composite (EP/NDs) with 4phr nano-diamond were placed in a high temperature aging chamber and sampled every two days to determine their macro properties. The study found that compared with EP/NDs, the breakdown voltage increased by 10.25% after aging, the volume resistivity decreased by two orders of magnitude, and it was more stable. Through molecular dynamics simulation analysis, it is found that the Fermi level of diamond is higher than that of epoxy resin matrix. Due to the difference in energy level, the high-energy electrons in diamond tend to move to the resin matrix with lower energy level, resulting in negative charge on the diamond surface, which changes the migration of electrons in the material and improves the breakdown performance.