Thermal and electrical conductivity of Al(OH)3 covered graphene oxide nanosheet/epoxy composites

Al(OH)₃ functionalized graphene composites (Al–GO) were prepared using a simple sol–gel method. In this protocol, graphene oxide (GO) was prepared according to the Hummers method and functionalized to enhance its reactivity with aluminum isopropoxide by a LiAlH₄ treatment. The functionalized graphene sheets were characterized by X-ray photoelectron spectroscopy, field emission scanning electron microscopy, and transmission electron microscopy. These analyses confirmed that GO had been fabricated and the Al(OH)₃ layer could have a homogeneous distribution with large and dense coverage onto GO sheets. In addition, the thermal and electrical conductivity of the epoxy composites with GO and Al–GO fillers were measured. The thermal conductivities of the composites with graphene-based fillers were enhanced by the addition of fillers. In particular, the thermal conductivity of GO/epoxy composite containing 3 wt% was approximately two times higher than that of pure epoxy resin. In addition, the electrical conductivity of Al–GO embedded composites degenerated compared to GO composites.