Synergistic optimization of multifunctional properties in carbon fiber/phenolic composites by designing array carbon nanotubes structures on the surface of carbon fibers

Carbon fiber/phenolic resin composites have great potential application in the field of electronic information, where excellent structural-functional integration is required. In this work, the establishment of interfacial structures consisting of carbon nanotubes with different morphologies at the fiber/matrix interface is conducive to the further modulation of the mechanical, tribological, electromagnetic interference (EMI) shielding and thermal conductivity properties of carbon fiber/phenolic resin composites. Specially, array carbon nanotubes can deep into the resin matrix, effectively hindering crack extension, and constructing an electrically and thermally conductive network. Compared with the carbon fiber/phenolic composites, the tensile strength and modulus of elasticity (163.86 ± 9.60 MPa, 5.06 ± 0.25 GPa) of the array carbon nanotubes reinforced carbon fiber/phenolic composites were enhanced by 57.09 % and 22.22 %. The average friction coefficient and wear rate (0.20 ± 0.02, 1.11 × 10⁻¹³ ± 0.13 × 10⁻¹³ m³ N⁻¹ m⁻¹) were reduced by 39.39 % and 74.31 %. EMI shielding effectiveness up to 40 dB in the X-band at 0.4 mm sample thickness, diffusion coefficient (0.39 ± 0.003 mm²/s) and thermal conductivity (0.54 ± 0.004 W/(m K)) were enhanced by up to 14.37 % and 50.42 %. This study reveals the beneficial effects of morphological changes of carbon nanotubes on the design of interfacial structure, proposes the reinforcement mechanism of array carbon nanotubes, and opens up the prospect of carbon fiber/phenolic composites for electronic applications.