Abstract

The low thermal conductivity of polymer matrices limits the use of carbon-fiber reinforced plastics (CFRPs) in thermal management applications. To enhance heat transfer properties while preserving the excellent mechanical characteristics of CFRPs, we proposed a fabrication method for a high-thermal-conductivity composite using graphite sheet (GS) stacking and pitch-based carbon fiber stitching. We then evaluated its thermal and mechanical properties. Thermal conductivity was determined by measuring specific heat, density, and thermal diffusivity, while the through-thickness reinforcement effect of the proposed structure was assessed by double-cantilever beam testing. Results showed that the proposed method significantly improved both in-plane and through thickness thermal conductivity, surpassing that of untreated polyacrylonitrile (PAN)- based carbon/epoxy composites. A dynamic heat transfer analysis using a heat element and thermocouples further clarified the mechanism underlying the enhanced thermal performance. Additionally, the effects of GS insertion and pitch-based carbon fiber stitching on the z-direction reinforcement were examined. While GS insertion reduced the failure load, pitch-based carbon fiber stitching increased it. Thus, the proposed approach effectively enhances the thermal properties of conventional PAN-based carbon/epoxy composites.