Study Of Electrical Properties Of Graphene/Epoxy Resin Composites Induced By External Electric Field

With the continuous development of aerospace technology,composite materials have gradually replaced metal materials and been used more and more in aircraft manufacturing,which greatly reduces the weight of aircraft.However,compared with traditional metal materials,the electrical conductivity of the composite material is lower,when the aircraft is struck by lightning,the composite material is difficult to conduct lightning currents,posing a threat to the safety of the aircraft.The aim of this paper is to improve the electrical conductivity and lightning resistance of resin-based composites,so that they can be better used in aerospace field.Graphene and carbon nanotubes are used as conductive fillers to add to epoxy resin,and an external electric field is applied.The excellent conductivity of graphene and carbon nanotubes is utilized to form a conductive path under the induction of electric field,so as to improve the conductivity of composite materials.Specific research contents are as follows:（1）Graphene was added to the epoxy resin as a conductive filler by solution blending method,and external electric field was applied to make the graphene orderly arranged in the epoxy resin,forming a conductive path and thus improving the conductivity of the composite material.Scanning electron microscopy（SEM）showed that without electric field,graphene aggregated seriously and distributed unevenly in epoxy resin.When a 60V electric field was applied,the graphene was oriented and more evenly distributed,with only a few agglomerations.According to the conductivity test results,the conductivity of the composite prepared by applying 60 V voltage for 10 min with 3 wt%graphene content is 2-3 orders of magnitude higher than that of the composite without applying electric field,indicating that the electric field induction method can effectively improve the conductivity of the composite.（2）Carbon nanotubes were then added to the epoxy resin as conductive fillers and an electric field was applied.The excellent length-diameter ratio of carbon nanotubes can be used to improve the conductivity of composite materials,and the larger the length-diameter ratio,the smaller the seepage threshold of conductive materials.According to the scanning electron microscope test results,the arrangement of carbon nanotubes with electric field applied is more orderly than that without electric field applied.According to the conductivity comparison results,the conductivity of the composite prepared by applying 60 V voltage for 10 min is 1order of magnitude higher than that of the composite without electric field applied.（3）Finally,graphene and carbon nanotubes were added to the epoxy resin as conductive fillers,and electric field was applied to explore the synergistic effect of graphene and carbon nanotubes under electric field induction.The results show that when the mass ratio of graphene to carbon nanotubes is 1:2,the conductivity of the composite can reach 5.4×10^-2 S/m.In the graphene/carbon nanotube/epoxy resin composite,carbon nanotube is seen as a bridge connecting the graphene sheets,forming an orderly conductive network by SEM.