Enhanced thermal and mechanical properties of polyamide-based carbon fiber composites via radial carbon network: Insights from microstructural engineering and interfacial compatibility

The synergistic optimization of thermal management and mechanical properties is a central challenge for the application of carbon fiber composites in high power electronics and lightweight structures. In this study, a multiscale synergistic strategy of “radiation freezing-interfacial welding-in situ interlocking” was proposed to successfully prepare three-dimensional (3D) polyamide composites reinforced by radial carbon networks. Through directional freezing to induce the formation of radially oriented interpenetrating networks between carbon fibers and graphene oxide, combined with stepwise thermal reduction to construct carbon-carbon covalent interfaces, and in-situ polymerization to achieve matrix chain segment penetration and interfacial stress transfer reinforcement. At 12 wt% filler loading, the composite achieved a thermal conductivity of 3.41 W m⁻¹ K⁻¹ (1605 % improvement over the matrix), along with compressive strength of 173 MPa, which breaks through the inverted performance limitations of polymer composites. This work provides a new material design paradigm for electronic packaging and aerospace lightweight structures and its cross-scale interface engineering strategy opens up new paths for the development of multifunctional composites.