Role of Graphitization-Controlled Conductivity in Enhancing Absorption Dominated EMI Shielding Behavior of Pyrolysis-Derived Fe3C@C-PVDF Nanocomposites

Abstract The role of improved graphitization-induced conductivity on imparting better electromagnetic interference (EMI) shielding effectiveness (SE) in the X-band frequency regime is demonstrated. Variation of synthesis temperature (Ts) is used as a strategic tool to modulate the graphitization and the associated conductivity. Two different carbonaceous-nanomaterials, both embedded with graphite encapsulated Fe3C-nanoparticles were synthesized at Ts = 800 °C (Fe-800) and Ts = 1000 °C (Fe-1000). We have shown that a higher synthesis temperature results in a thicker well-graphitized carbon-shell around the core (Fe3C) nanoparticles. The better degree of graphitization makes the samples better conducting. These two samples were dispersed separately in flexible polyvinylidene fluoride (PVDF) matrix to form polymer-nanocomposites. The SE of the PVDF:Fe-1000 nanocomposite film is higher than that of the PVDF:Fe-800 nanocomposite film. This high SE of the PVDF:Fe-1000 nanocomposite film is associated with the higher conductivity resulting from the higher degree of graphitization of the Fe-1000 sample. Effectively, the synergetic effects of electric and magnetic losses enhance the absorption-dominated EMI shielding of our nanocomposite-system, making them potential candidates for their direct industrial applications. Simultaneously, our work provides a strategy to control the EMI-SE of nanocomposites through control of the synthesis parameters.