The Effect Of Graphene On The Electromagnetic Shielding Properties Of Carbon Fiber/Polymer Composites

With the problem of electromagnetic interference?EMI? becoming increasingly serious, the quest for lightweight and efficient EMI shielding materials has become an urgent need to study. Graphene is a kind of ideal EMI shielding material due to the excellent properties, such as low density, high specific surface, and high conductivity. In this paper, reduced graphene oxide?rGO? was introduced onto carbon fiber?CF? surface, and rGO-Fe₃O₄ hybrid was prepared by decorating nano Fe₃O₄ particles on to rGO sheet to improve the level of impedance matching and the electromagnetic shielding property of CF/polymer composites.The surface modification of CF with GO and rGO were investigated. The microstructure and chemical structure of GO-CF and rGO-CF were analyzed by SEM, FTIR, and XPS. The results show that GO-CF were coated with wrinkled GO sheets, and most of the oxygen-containing groups on GO-CF were removed after reduction process.Prepared composites by blended GO-CF and rGO-CF with unsaturated polyester resin?UP?, and the EMI shielding effectiveness?SE? and shielding mechanism were investigated. The rGO-CF was found to be more effective than GO-CF in improving SE value of composites. With 0.75 wt% of rGO-CF, the SE value of composite reached 37.8 d B at 12.4 GHz, which had 16.3% and 8.9% increase than CF/UP and GO-CF/UP respectively. The suitable electrophoretic deposition experiment condition was determined for 60 min, 21 V through the single factor variable experiment.The XRD, FTIR, SEM, TEM, TG, and VSM verified that the nano Fe₃O₄ particles were uniformly immobilized onto GO sheets with the size of 50 nm. The minimum reflection loss of rGO-Fe₃O₄/wax was-22.7 dB at 12.09 GHz when the thickness of sample was 3.0 mm.The rGO-CF and rGO-Fe₃O₄ were blended with epoxy resin?EP? to improve the EMI shielding property. With 0.75 wt% of rGO-CF and 3 wt% of rGO-Fe₃O₄, the composite SE value was 38.3 dB at 18.0 GHz, which had 29.4% improvement than rGO-CF/EP. The improvement of SE value is mainly due to the synergistic effect between rGO-CF and rGO-Fe₃O₄.