Synergistically enhanced electromagnetic interference shielding and mechanical properties of epoxy resin composites with a preconstructed hierarchical structure

Electromagnetic interference (EMI) shielding materials have attracted extensive attention as highly integrated electronic devices generate large amounts of electromagnetic pollution. Here, PNF/NGx-EP composites with excellent EMI shielding properties and superior flexural strength were reported, where nickel-plated carbon fiber (NF) felts and NH2-Graphene (NG) were adopted to pre-construct a hierarchical structure within epoxy resin (EP). The macroscopic NF network constructed a continuous conductive pathway and the NG grafted on the surface of NF formed a second microscopic conductive network. Consequently, the PNF/NG0.5 felts exhibited a quite high electrical conductivity of 138.4 S/cm, and the PNF/NG0.5-EP composites presented excellent EMI shielding effectiveness (EMI SE) (57.4 dB at 11.9 GHz). Intriguingly, the flexural strength of the NF/EP composites was enhanced after the incorporation of NG, which was attributed to the mechanical locking effect and covalent bonding. In summary, this approach reconciles the contradiction between EMI shielding properties and mechanical properties of EP composites, and allows them to be promisingly employed for EMI shielding and protection in aerospace, weaponry, and communications.Highlights A hierarchical structure of PNF/NGx felts was preconstructed within EP via Michael addition/Schiff base reaction. The PNF/NGx-EP composites exhibited remarkable EMI shielding properties (57.4 dB) and superior flexural strength (137.0 MPa), which are expected to realize practical applications in EMI shielding. Hierarchically structured EP composites with excellent EMI properties and favorable flexural strength. image