Flexible silicone rubber/carbon fiber/nano-diamond composites with enhanced thermal conductivity via reducing the interface thermal resistance

Abstract Insulating materials with heat dissipation are urgently required for modern electronic devices and systems. In this study, 4,4-methylene diphenyl diisocyanate was used as the coupling agent, and nano-diamond (ND) particles were grafted onto the surface of carbon fibers (CFs) to prepare CF-ND/silicone rubber (SR) composites. The ND acted as a “bridge” among CFs, which can reduce the interface thermal resistance between CFs because the dot-like ND can increase the interfacial area of CFs, making it easier to form heat-conducting networks between SR. When the content of CF-ND (1:6) was 20%, the thermal conductivity of the SR composite was 0.305 W/(m·K), 69% higher than that of pure SR. The ND between CFs can improve the dynamic mechanical properties by acting as a crack pinhole. In addition, the CF-ND/SR composites also exhibited excellent thermal stability. This work has enormous potential for advanced electronic devices.