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

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.