Effect of barium strontium titanate modification on the dielectric-breakdown properties of phenyl-vinyl binary composite silicone rubber

Silicone rubber has been widely used in electric power equipment for its excellent insulation performance and weather resistance. However, the weak breakdown characteristic of silicone rubber limits its application in high-voltage grade power equipment. In this paper, the nano-modification system of silicone rubber based on a binary composite matrix of “phenyl-vinyl” was constructed. On the one hand, the benzene ring structure is introduced to improve the breakdown strength of the matrix. On the other hand, barium strontium titanate (BST) is used to improve the permittivity of composite, reducing the electric field shared by silicone rubber. The experimental results show using binary composite silicone rubber as the matrix, the appropriate amount of BST filling can greatly improve the permittivity of the composite. When the BST content is 30 wt%, the permittivity of the binary composite reaches the maximum value of 3.98, which is about 49.06% higher than that of vinyl silicone rubber. Accordingly, the electric field strength shared by silicone rubber insulation will decrease significantly. Meanwhile, the moderate amount of BST in the matrix can improve the breakdown strength. This work is an important guideline for the performance improvement of silicone rubber for high-voltage power equipment.