Self-templating graphene network composites by flame carbonization for excellent electromagnetic interference shielding

Graphene networks (GNs) with ultralow density of 5.6-8.6 mg/cm(3) were prepared with polyurethane/graphene (PUG) composite foams as templates and ethanol flame as a mild carbonizing condition. After the pyrolysis of the PU matrix in dozens of seconds, the structural integrity of the foams was well preserved by the embedded graphene sheets at a sufficient content (>= 12 wt%), forming interconnected GNs with pore size in nano- and micron-scale. When encapsulated with epoxy resin, the CNs composites showed excellent electrical conductivity of 340-830 S/m at the filler content of 2.5-4.2 wt% and exceptional electromagnetic interference (EMI) shielding effectiveness (SE) of 30-61 dB in sample thickness of 0.9-1.5 mm. The excellent EMI shielding property of GN composites, as well as the mild, high-efficient flame-carbonizing process, make our self-templating method very promising in the facile fabrication of high-performance EMI shielding materials.