In-situ constructing continuous networks composed of SiC nanowires for enhancing the thermal conductivity of epoxy composites

Abstract

With the rapid miniaturization and high degree of integration of modern electronic devices, there is an increasing demand for high-performance polymer-based thermal management materials. SiC nanowires (SiCNWs) are very promising fillers benefiting from their large aspect ratio and ease of constructing thermally conductive networks. However, the traditional random mixing method allows the SiCNWs to form a thermally conductive network only through physical overlap, resulting in a high interfacial thermal resistance. To address this problem, an innovative strategy for in-situ generating continuous network composed of SiCNWs was proposed in this study, in which the SiCNWs was formed through impregnation-sintering process using an inexpensive polyurethane (PU) sponge as a template. The porous skeletons were sintered by numerous SiCNWs, which not only conferred more thermally conductive pathways, but also solved the problem of weak bonding at the SiCNWs random lap interface. On this basis, the SiC skeletons were further used as reinforcement to prepare epoxy (EP)-based composites. Benefiting from the continuous thermally conductive networks composed of SiCNWs, the composites achieved a thermal conductivity (TC) of ∼1.17 W m−1 K−1 at a low volume fraction of 21.18 vol%, which was 548.7 % higher than that of pure EP. In addition, the unique SiCNWs skeletons also facilitated the enhancement of mechanical properties and thermal stability of the composites, providing new insight for the preparation of innovative thermal management materials.