Understanding the dielectric properties of silicone rubber-BN nanocomposites under DC voltage

The present study explores the dielectric and structural properties of silicone rubber composites with low-weight percentages of boron nitride (BN) fillers aimed at insulation applications. The incorporation of BN fillers into the silicone rubber matrix significantly enhances the glass transition temperature (Tg), melting temperature (Tm), and crystallization temperature (Tc). Notably, the dielectric constant increases while the loss factor remains minimal with a low concentration of BN fillers with silicone rubber matrix. J-V characteristics from space charge limited current (SCLC) measurements were employed to evaluate trap density. The addition of 3 wt% BN filler notably improves the crossover voltage and trap density in the silicone rubber matrix. A strong correlation has been observed between trap density values derived from SCLC measurements and surface potential decay experiments. Furthermore, the SCLC measurements at different temperatures exhibit an Arrhenius behavior, providing insights into the charge transport and trapping mechanisms. Overall, the experiment results indicate that the inclusion of 3 wt % of BN filler has significant improvement in dielectric as well as charge trap characteristics.Highlights BN filler impacts permittivity and tan (delta) based on concentration levels. Differential scanning calorimetry shows crystallinity changes with increased BN filler in silicone rubber. Surface potential relates to J-V characteristics, following SCLC mechanism. Arrhenius relation to temperature-based SCLC shows thermally activated conduction. Trap density trends align in SCLC and surface potential decay methods.