Influence of molecular chain motion property in interfacial regions on dc breakdown property of polyethylene nanocomposites

Microscopic property changes are the basis of the macroscopic variations. it is important to obtain the material with high performance and durable stability, however, revealing its hidden mechanism is more crucial. In this way, we can modulate the property of nano dielectric by selecting different matrix, nano particle, synthesis condition and other factors to design the material that meets the requirements. In our research, we attached more emphasis to the microscopic charge migration.

This project focuses on revealing the electrical breakdown mechanism of polyethylene nanocomposite. We built the electron transport and molecular displacement model to depict the charge behavior in the bulk of insulating dielectric system. This model considers the charge injection, migration, trapping/detrapping and recombination as a dynamic process and depicts the continuous motion process of charges in the bulk of dielectrics. By setting boundaries of the model and solving Poisson’s equation, this model can be used for calculating the charge transport property in the bulk of insulating material, including numerical calculation of space charge and electric field distribution, energy gained by electrons as well, as electrical strength. This model was once used for explaining the electrical breakdown behavior of polypropylene (PP, used for the film of power capacitor) nanocomposite. By combining the experimental results and calculation of the model, the hidden electrical breakdown mechanism of nanocomposite was revealed.