Mechanical Properties and Thermal Conductivity of Epoxy Composites Containing Aluminum-Exfoliated Graphite Nanoplatelets Hybrid Powder

Epoxy/aluminum-exfoliated graphite nanoplatelet (Al-xGnP) composites were prepared. Prior to the preparation of the composite, two types of Al-xGnP hybrid powder were prepared, one is fully inserted xGnP in aluminum (Al) flake and the other is partially inserted xGnP in Al flake, which were confirmed by TEM images. The thermal conductivities of the epoxy composites increased monotonically with the filler content and the partially and fully inserted epoxy/Al-xGnP composites showed almost 2-3 times higher than those of epoxy/xGnP and epoxy/Al composites. Especially, partially inserted epoxy/Al-xGnP composite showed the highest values of thermal conductivity at the same filler concentration because of the network bridge between Al flakes. The tensile and flexural moduli of the fully inserted epoxy/Al-xGnP showed the highest value in all areas of the filler content because of the good dispersion quality but the tensile and flexural strengths of all epoxy composites decreased with the filler content due to the increase of weak interface between epoxy matrix and the filler.