Preparation and Properties of Polyaniline/Different Magnetic Nanoparticles Modified Carbon Fiber Composite Paper

ABSTRACT To synergistically enhance the dielectric and magnetic losses of carbon fiber (CF) paper‐based composites, the surface of CFs was modified with nano‐Fe 3 O 4 , nano‐FeNi 3 , and flake nano‐FeNi 3 (LFeNi 3 ) magnetic nano‐alloys combined with polyaniline (PANI). A series of modified CF/plant fiber electromagnetic interference (EMI) shielding papers were fabricated via wet papermaking and hot pressing. The results showed that the magnetic nanoparticles were uniformly deposited on the CF surface along with PANI. Among the magnetic materials, LFeNi 3 exhibited the highest saturation magnetization (87.5 emu/g) and coercivity (60.5 Oe), demonstrating its superior ferromagnetic properties. The tensile strength of the P‐LFeNi 3 @PACF reached 3.1 kN/m, which was 47.6% higher than that of the unmodified CF paper. In X‐band, the total EMI shielding effectiveness (SE T ) of P‐LFeNi 3 @PACF reached 37.90 dB, representing increases of 46.7% and 22.8% compared with unmodified CF paper and pure PANI‐modified paper, respectively. It is found that the reflectivity ( R ) values are significantly higher than the absorptivity ( A ) values, indicating that the experimentally measured shielding behavior is actually reflection‐dominated. P‐LFeNi 3 @PACF exhibited the strongest dielectric and magnetic loss capabilities. Via morphological control of magnetic nanoparticles and synergistic modification with PANI, the EMI shielding performance of CF paper‐based composite can be significantly enhanced. This strategy offers an economical and practical approach for preparing high‐performance multifunctional EMI shielding materials.