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The current study reports the preparation of polycarbonate (PC) nanocomposite using graphite flake (GF) and multi-walled carbon nanotube (MWCNT) at varying weight percentages (10%, 20%, and 30%) by the melt mixing technique. The impact of filler on the properties of thermal conductivity (TC), electromagnetic interference shielding (EMI), electrical, and mechanical of the nanocomposite were studied. The improvement in the thermal conductivity value of >150% was achieved at a loading of 30% of graphite flake and 20% multiwalled carbon nanotubes. The morphology of the composite studied by field emission scanning electron microscope (FESEM), confirmed the dispersion of filler in the PC matrix. The electrical conductivity of both the optimized compositions achieved was in the order of 10 À2 S/cm. Further, the EMI shielding of $35 and $32 dB was observed for graphite flake and MWCNT based composites, indicating the suitability of the developed system for various commercial applications.

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The current study reports the synthesis of expanded graphite (EG) in two different ways and its fabrication with epoxy matrix to form composite at various filler fractions (5, 10, 12.5). One type EG (EG-C) is prepared by the electrochemical process using natural graphite flake (NGF), concentrated sulfuric acid, and ammonium persulfate, while the other (EG-P) is just mixing and heating of NGF with zinc nitrate hexahydrate. The functional groups of synthesized EG were confirmed by Fourier transform infrared spectroscopy. The surface morphology and microstructure of synthesized filler (EG-C, EG-P) were studied using X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. An optimum through-plane thermal conductivity (TC) of 2.04 and 2.22 W/mK was observed in the case of the composites containing 12.5 wt% of EG-C and EG-P, respectively. The obtained experimental TC was compared with three numerical thermal models, that is, inverse rule of mixture, Maxwell–Eucken model, and Agari model. Furthermore, the thermal stability of both composites was compared by using a thermogravimetric analyzer. The electrical resistivity of EG-P/epoxy composite at different formulations was higher than the EG-C-filled epoxy composites.