Enhancing the interfacial and electromagnetic shielding properties of CF/EP composites via Fe-based MOFs in situ pyrolysis

The interfacial bonding performance between carbon fibers and the resin matrix is a critical factor limiting the performance optimization of carbon fiber reinforced polymer composites. This work utilizes Fe 3+ as the iron source and fumaric acid as the organic ligand to construct the precursor of iron-based metal–organic framework (MIL-88-A) through in situ growth on carbon fiber surfaces. Subsequently, the grafting of magnetic Fe 3 O 4 nanoparticles onto carbon fiber surfaces was accomplished via a pyrolytic treatment. These modified carbon fiber reinforced epoxy composites were then fabricated using vacuum-assisted resin infusion (VARI). The results indicate that the interfacial shear strength (IFSS) and interlaminar shear strength (ILSS) of the Fe 3 O 4 nanoparticle-modified CF/EP composites reached 106.4 MPa and 68.8 MPa, respectively, representing significant improvements of 63.7% and 48.9% compared to those of the desized carbon fiber composites. This enhancement can be attributed to the fact that the magnetic Fe 3 O 4 nanoparticles not only improved the wettability between the carbon fiber surface and the epoxy resin but also increased the surface roughness of the fibers, thereby enhancing mechanical interlocking and stress transfer efficiency in the interfacial region. Meanwhile, owing to the presence of magnetic Fe 3 O 4 nanoparticles, the CF/EP composites exhibit outstanding electromagnetic shielding performance with an average shielding effectiveness of 47.1 dB in the X-band. This study offers new design insights for improving the interfacial properties of carbon fiber-reinforced polymer (CFRP) composites and expanding their multifunctional applications.