Lightweight Epoxy/Cotton Fiber-Based Nanocomposites with Carbon and Fe₃O₄ for Electromagnetic Interference Shielding

Cotton fiber (CF)-based electroconductive papers were prepared by facile aqueous dispersion and drying processes combined with carbon nanotubes (CNTs) or graphene nanosheets (GNPs). To enhance the electromagnetic interference (EMI) shielding performance of the manufactured nanocomposites, the electroconductive papers were soaked with epoxy resin, which cooperated with the inner sprayed Fe₃O₄ nanoparticles. The EMI shielding effectiveness of Epoxy/CF-30-Fe₃O₄-30GNPs reached 33.1 dB, of which over 85.0% is attributed to absorption, which is mainly believed to be caused by the combination of GNPs and Fe₃O₄ nanoparticles due to their special structures and synergetic effects. Moreover, the infiltration of epoxy between the randomly distributed loose CFs and the multiple reflections inside the interconnected networks could also help to improve the EMI shielding performance of GNP-added samples. The prepared lightweight and stiff Epoxy/CF-30-Fe₃O₄-30GNP composites have promising applications in civil or military fields.