Probing the Surface Treatment Type of Aluminum Hydroxide in Silicone Rubber Composite Using Broadband Dielectric Response

The premature aging of silicone rubber housing in composite insulator applications has emerged as a significant challenge. The numerous internal interfaces introduced by functional fillers are hypothesized to play a crucial role in this phenomenon. However, the current standard methods are inadequate for characterizing the interfacial state, which is largely determined by the surface treatment of the filler. In this research, we utilize dielectric response analysis to investigate the interfaces introduced by ATH filler. The results obtained can be delineated into two groups at elevated temperatures, based on the surface treatment of the ATH filler, and this classification remains consistent across a wide range of filler contents. Consequently, dielectric response emerges as an effective, nondestructive method for characterizing the surface treatment type of ATH filler. The detailed procedures for this analysis are illustrated herein. Specifically, the real and imaginary part of permittivity at high frequencies can serve as a validation check for sample preparation and measurement accuracy. Then, the real part of permittivity at mid frequencies can be employed to differentiate between various filler types.