Strengthened epoxy nanocomposites with binary fillers of magnetite@polyaniline and carbon nanofiber for high-performance thermal stability electromagnetic wave absorption

To address the electromagnetic wave pollution issue induced by widespread applications of electronic devices and 5G technology, multifunctional epoxy composites reinforced with both 0-D magnetite (Fe3O4)@polyaniline with a core–shell structure and 1-D carbon nanofibers were prepared by the in situ polymerization method. The nanocomposites exhibit good mechanical properties, thermal stability, and electromagnetic wave absorption performance. The reflection loss can be −55.73 dB at 7.17 GHz, and the effective absorption bandwidth can reach 1.96 GHz at 3.2 mm. The excellent electromagnetic wave absorption performance is related to the magnetic loss (eddy current loss, magnetic resonance) and dielectric loss (interfacial polarization loss, dipolar polarization loss, and conduction loss). Moreover, when the mass ratio of 0-D Fe3O4@polyaniline to 1-D carbon nanofiber is 48:1, the tensile strength is improved to 47.8 MPa compared with epoxy composites with only Fe3O4@polyaniline particles. Meanwhile, the thermal stability and thermal conductivity of the multifunctional epoxy composites were systematically analyzed as well. This work provides a new idea to prepare the multifunctional epoxy composites with excellent electromagnetic wave absorption performance.