Anisotropic Thermally Conductive Polyurethane Composites Based on Tannic Acid-Modified Silicon Carbide/Woven Fiber Skeletons

With the miniaturization of electronic devices, the demand for high-efficiency thermal management materials has become increasingly urgent. Although traditional high-filler random blending composites can enhance thermal conductivity, they often do so at the expense of mechanical properties and lightweight advantages. Therefore, constructing oriented thermal conduction networks at low filler loadings has become a core challenge in current research. This study proposes an interface engineering strategy based on a tannic acid (TA) molecular bridging layer to modify silicon carbide (SiC). By leveraging the self-polymerization and strong adhesion properties of TA, a dense fish scale SiC coating was formed on the surface of highly oriented woven cellulose acetate (WF) through a simple impregnation process. After compositing with a polyurethane (PU) matrix, the obtained WF/TA/SiC/PU exhibits anisotropic thermal conductivity. It has an axial thermal conductivity of 0.44 W/mK, an increase of 411% over PU, and the decomposition temperature has increased by 18.2 °C. Additionally, the composite axial thermal response rate significantly outperforms both the radial direction and PU. This research demonstrates a new approach for achieving high-efficiency thermal management at low filler loadings, providing a scalable pathway for the development of sustainable, lightweight, and high-performance anisotropic heat dissipation devices.