▎ 摘　　要

The two-dimensional structure and unique properties make graphene an efficient candidate to strengthen the electrical and mechanical characteristics of polymer composites. The effectiveness for improving the electrical property of composites strongly depends on the size, electrical conductivity and dispersion of graphene fillers in polymer matrix. Here, we demonstrate that Raman spectroscopy can be used to study the dispersion of conductive graphene layers in epoxy composite. The graphene area fraction obtained fromRaman images shows a percolation threshold of around 25%, where a conductive network is formed within the epoxy matrix, which agrees well with conductivity results. Furthermore, it is observed that the conductivity and distribution of graphene in epoxy composites are highly influenced by the mixture temperature of graphene and epoxy system. Our results provide a strategy to effectively monitor the dispersion of graphene and study its relation with the properties of composite materials. Copyright (c) 2016 John Wiley & Sons,