Enhanced thermal and electrical performance of silicone rubber composites reinforced with graphene oxide and hexagonal boron nitride for advanced thermal management

Efficient heat dissipation is essential in modern high-performance electronics, where increasing power density and device miniaturisation create significant thermal management challenges. In this study, room-temperature vulcanised silicone rubber (RTV-SR) was reinforced with hybrid fillers—graphene oxide (GO) and hexagonal boron nitride (hBN)—to develop multifunctional composites with optimised thermal, mechanical, and electrical properties. The effects of filler type, concentration (5–20 wt%), and chemical surface modification using 3-aminopropyltriethoxysilane (APTES) were systematically investigated. Incorporating GO–hBN hybrids increased thermal conductivity by up to 185% (from 0.21 to 0.60 W·m − 1·K − 1) and improved thermal stability by 27 °C (T 50 shift), while enhancing tensile strength by 32% and Young’s modulus by 40% compared with pristine RTV-SR. The synergistic balance between the thermally conductive yet electrically insulating hBN and the mechanically reinforcing GO enabled simultaneous thermal enhancement and dielectric integrity, with dielectric strength increasing by 18% and electrical conductivity reduced by an order of magnitude compared to GO-only systems. Surface functionalisation with APTES ensured uniform filler dispersion, minimising agglomeration and further improving both mechanical and functional performance. These results position hybrid-filler RTV-SR composites as promising candidates for high-efficiency thermal interface materials, flexible dielectric layers, and mechanically robust components in electronics, automotive systems, and aerospace applications. Beyond these immediate uses, the findings provide a scalable design strategy for engineering next-generation silicone-based composites with tailored multifunctional performance.