Mechanical and wave absorption properties of <scp>Fe₃O₄</scp>‐deposited <scp>B</scp>uckypaper reinforcing epoxy resin composites

Abstract There are increasing need for the development of electromagnetic wave‐absorbing materials since the growing concern about electromagnetic interference. However, materials with integrated structure and function are difficult to attain due to the high content of functional fillers. In this paper, carbon nanotubes (CNTs) were formed into a three‐dimensional porous framework, known as Buckypaper (BP), which was subsequently in situ deposited with iron tetraoxide (Fe 3 O 4 ) through the sol–gel method and incorporated into epoxy resin to create Fe 3 O 4 /BP/EP composites by hot pressing. The three‐dimensional porous structure of Fe 3 O 4 /BP facilitates the high‐content incorporation and uniform dispersion of CNTs and Fe 3 O 4 nanoparticles. The results indicate that the 33%Fe 3 O 4 /BP/EP composite achieved an optimal reflection loss of −38.41 dB and an absorption bandwidth of 3.28 GHz at the optimal matching thickness of 1.5 mm. This performance primarily stems from Fe 3 O 4 adjusting the impedance matching of BP and enhancing the magnetic loss capability of CNTs. Furthermore, the deposition of Fe 3 O 4 on BP improves the mechanical strength of BP/EP, The 17% Fe 3 O 4 /BP/EP composite achieves a tensile strength of 35.09 MPa, which is 46.27% higher than that of BP/EP and 92.38% higher than pure EP. Highlights Fe 3 O 4 /BP was prepared by deposition of Fe 3 O 4 onto surfaces of the CNTs framework. Fe 3 O 4 /BP/EP composites with different Fe 3 O 4 /BP were fabricated. Fe 3 O 4 adjusts impedance matching of BP, and forms heterogeneous interfaces. Fe 3 O 4 /BP/EP composites exhibit excellent wave absorption performance. Fe 3 O 4 /BP/EP composites possess improved mechanical properties.