Role of cashew shell biochar on EMI shielding behaviour of carbon fibre-epoxy nanocomposites in E, F, I and J band-microwave frequencies

This research discusses about the effect of adding high content cashew shell biochar (CSB) nanoparticle onto the carbon fibre-reinforced epoxy resin composite in electromagnetic interference (EMI) shielding behaviour. The primary goal of this research was to study the EMI shielding behaviour of CSB particle addition in carbon-epoxy composite at elevated frequency ranges up to 18 GHz. The shielding epoxy composites were prepared via hand layup method followed by characterized in accordance to ASTM standards. It is noted that the addition of CSB particle increased the mechanical properties of carbon-epoxy composite up to 226 and 298 MPa in tensile and flexural properties of composite designation CS4. The scattering parameters of tested composites showed highest reflection, multi-reflection and absorption behaviour for high CSB content in composite. It is further noted that the shielding effect increased with the volume of CSB particle. A highest shielding of - 48.6 dB was observed for composite designation CS5 at 18 GHz. These EMI shielding behaviours improved biochar-epoxy composites which could be used in radar, telecommunication, defence and signal processing devices where the effect of interference needs to be reduced.