Surface Modification of Carbon Fiber Based on Tannic Acid and PAMAM ‐Functionalized Fe 3 O 4 for Synergistic Enhancement of Mechanical and Electromagnetic Interference Shielding Properties in Composites

ABSTRACT The poor compatibility between carbon fibers (CF) and resin matrices limits the application of carbon fiber composites. Inspired by mussel adhesion, a TA coating was deposited on the carbon fibers, serving as a reactive platform to successfully introduce polymer‐modified Fe 3 O 4 nanoparticles onto the surface to enhance the surface activity and roughness of the fibers, thereby improving the mechanical properties of the composites. The results show that the MCF/EP composites exhibit superior flexural strength compared to unmodified CF/EP composites. The interlaminar shear strength (ILSS), and electromagnetic interference (EMI) shielding effectiveness (SE) were increased by 69%, 23.4%, and 114%, respectively. This work provides reference for the development of high‐performance, multifunctional carbon fiber composites with potential applications in fields such as aerospace.