Preparation of continuous carbon fiber-filled silicone rubber with high thermal conductivity through wrapping

Abstract

With the development of electronics, there is an increasing demand for high-performance heat-dissipation materials in electronic devices. Thermal conductive silicone rubber (SR) has received significant attention in related industries due to its excellent mechanical flexibility and high thermal conductivity. However, the intrinsic thermal conductivity of SR is low, necessitating the addition of thermal conductive fillers to meet the usage requirements. Common thermal conductive fillers typically exist in powder form and require such surface modification and orientation, which increases production costs and poses challenges for large-scale production. In this study, continuous carbon fibers (CFs) are utilized as fillers. By employing a simple pre-infiltration and winding method, CFs are uniformly distributed in SR, aligning parallel. The CFs not only serve as thermal conductive pathways but also maintain their orientation distribution within the substrate. Furthermore, by pre-adding boron nitride (BN) to the SR, the thermal conductivity of SR is enhanced, and BN is distributed along the fibers, further improving the enhancement effect of BN on the thermal conductivity of SR. When CF content reaches 30 vol%, the thermal conductivity of CF/BN/SR composite reaches 2.789 W m−1 K−1. Moreover, by using BN/SR before curing as a coating, it can be applied to the surface of the CF/BN/SR composite. This greatly increases the volume resistivity of the material (>1014 Ω cm) while maintaining the thermal conductivity of the composite. Using continuous fibers as fillers also enables easier implementation of mass production in the preparation of thermal conductive SR. Highlights: Prepare continuous carbon fiber and boron nitride (BN)-filled composite through mechanical winding; The carbon fiber (CF)/BN/silicone rubber (SR) composite exhibits high thermal conductivity; Improve the enhancement of BN on the TC of SR by aligning the BN along the CF; BN/SR used as insulating coating by incremental curing.