Construction of three-dimensional thermal conductivity structure on polyacrylonitrile based carbon fiber surface and the thermal conductivity improvement of its composite

Polyacrylonitrile-based carbon fibers (PAN-CF) are among the most widely used reinforcements in composite materials, characterized by their high specific strength and high specific modulus, which significantly enhance the mechanical properties of composites. Additionally, PAN-CF exhibits excellent axial thermal conductivity; however, its radial thermal conductivity is suboptimal. Coupled with the high thermal resistance of polymer matrices, this results in a substantial reduction in the out-of-plane thermal conductivity of composites. This study aims to enhance the radial thermal conductivity of PAN-CF and the out-of-plane thermal conductivity of carbon fiber composites through surface modification of PAN-CF. Initially, a three-dimensional hybrid network of nickel/carbon nanotubes (Ni/CNT) is electrodeposited onto the carbon fiber surface. Subsequently, vertically aligned graphene oxide (GO) is grafted onto CF@Ni/CNT through freeze-drying of a graphene oxide dispersion, followed by thermal reduction treatment to obtain CF@Ni/CNT@TRGO. At a filler content of 60% vol, the thermal conductivity of CF@Ni/CNT@TRGO-C reaches 1.98 W·(m·K)⁻¹, representing a 2.04-fold increase compared to PAN-CF-C. This study demonstrates that constructing continuous thermal conductive networks and vertical thermal conductive structures on the carbon fiber surface can significantly enhance the composites thermal conductivity , expanding the application of high-performance carbon fiber composites in the field of thermal management.