Structure and electric heating performance of graphene/epoxy composite films

We have prepared a series of graphene/epoxy composite films by thermal curing of diglycidyl ether of bisphenol-A with an amine-functionalized agent casted on a polyimide film, and investigated their structures and electrical properties as a function of graphene content of 0.0–10.0 wt%. X-ray diffraction patterns and TEM images show that graphene nanoplatelets are well dispersed in the epoxy resin matrix. The electrical resistance of the composite films varies dramatically from ∼1013 to ∼103 Ω with increasing the graphene content, especially at a certain graphene content between 1.0 and 2.0 wt%. Accordingly, electric heating behavior of the composite films with 2.0–10.0 wt% graphene is strongly dependent on graphene content as well as applied voltage. For the composite film with 10.0 wt% graphene, a maximum temperature of ∼126 °C is stably maintained over a cyclic voltage variation of 30 V. The excellent electric heating performance such as rapid temperature response, high electric power efficiency, and operational stability at applied voltages is believed to be owing to the presence of highly conductive graphene sheets interconnected in the thermosetting epoxy matrix.