Improved thermal conductivity for chemically functionalized exfoliated graphite/epoxy composites

Chemically functionalized exfoliated graphite-filled epoxy composites were prepared with load levels from 2% to 20% by weight. The viscosities of the composites having load levels >4% by weight were over the processing window for the vacuum-assisted resin transfer molding process. Wide-angle X-ray diffraction revealed a rhombohedral carbon structure in the filler. Enhanced interaction between the epoxy and the graphite filler was evidenced by an improvement in the rubber modulus for the chemically functionalized graphite/epoxy composites. The thermal and electrical properties of the nanoparticle-filled epoxy composites were measured. The electrical property of the chemically functionalized graphite/epoxy composite deteriorated. Thermal conductivity of the chemically functionalized graphite/epoxy composite, however, increased by 28-fold over the pure epoxy resin at the 20% by-weight load level, increasing from 0.2 to 5.8 W/m K. (C) 2008 Elsevier Ltd. All rights reserved.