Influence of Boron Nitride Particle Size on the Dielectric Strength of Silicone Elastomers

High-voltage (HV) plug-and-play connector systems have emerged as an emergency return to service solution for cable repair following an electrical failure. To enable compact, thermally efficient designs, reduced insulation volumes are desirable but can lead to increased localized electric field stress. Silicone elastomers are attractive for these applications due to their processability, dielectric performance, and mechanical resilience. However, unfilled silicones may lack sufficient dielectric strength for high-power scenarios. This study explores the incorporation of hexagonal boron nitride (BN) particles of varying their sizes into silicone elastomers to enhance dielectric performance. Through a combination of scanning electron microscope (SEM), Brunauer-Emmett-Teller (BET) surface area analysis, and electrical breakdown testing, we demonstrate that BN particle size significantly influences composite performance. Smaller particle sizes yield higher dielectric strength, while medium-sized fillers offer greater consistency in breakdown voltage. These findings inform the design of electrically robust materials for deployable HV connector technologies.