Nanonet encapsulating magnetic nanoparticles with double active layers and high structural stability on carbon fiber for composite interface enhancement and electromagnetic wave absorption

The structural stability of carbon fiber (CF) surface modification is vital for carbon fiber reinforcement polymer composites with harsh processing environments. To achieve it, CF anchored with magnetic Fe₃O₄ nanoparticles is designed to be encapsulated with an in-situ synthesized MoS₂@CNT-COOH nanonet (MCN). This encapsulation effectively prevents the shedding of Fe₃O₄ nanoparticles during composite processing and guarantee the interface and property stability of the composite. Additionally, this hierarchical structure comprises respective active oxidation layers and significantly boosts the interfacial compatibility and stress transfer between CF and Polyamide 6 (PA6) resin. Consequently, the tensile strength of MCN@Fe₃O₄-CF/PA6 composites is enhanced by 23.9 % compared to those of untreated-CF/PA6 composites. The synergistic effect of the high MCN dielectric loss in the outer layer and the stable Fe₃O₄ magnetic loss layer in the inner layer improves the composite electromagnetic wave (EMW) impedance matching and attenuation ability. The results present a minimum reflection loss value of −65.3 dB at a thinner thickness of 1.6 mm and maximum effective absorption bandwidth reaches 6.76 GHz at a thickness of 1.8 mm. The composite radar cross-section values are less than −10 dBm² at all tested detection angles. This CF surface modification method offers a novel and effective approach to manufacture high performance CF composite EMW absorbers with great stability.