Poly(methyl methacrylate)‐functionalized reduced graphene oxide‐based core–shell structured beads for thermally conductive epoxy composites

Thermally conductive epoxy nanocomposite with core–shell structured filler beads has been prepared. The core represents plasma‐treated poly(methyl methacrylate) bead, and the shell, amine‐functionalized reduced graphene oxide (frGO) sheets. The negatively charged core and the positively charged shell form core–shell unified structure through electrostatic attraction and the conductive bridges are formed among neighboring filler particles in the composite mass. The epoxy composite prepared with these core–shell structured filler shows a thermal conductivity of 0.72 W m−1 K−1 for an overall frGO concentration of as low as 0.96 wt %. Pal model has been applied to evaluate the effective thermal conductivity of frGO sheets that have been realized in the epoxy composition. Assuming the maximum possible volume packing fraction of the spherical beads for random jamming to be equal to 0.63, the effective thermal conductivity has been estimated as 280 W m−1 K−1. Evaluation of the effective thermal conductivity is a step forward to in‐depth study of real contribution of the highly conductive fillers in the polymer composites.