Preparation And Study On Properties Of Epoxy Composites Reinforced By Carbon Fiber

In this paper, a series of epoxy composites reinforced by carbon fiber wereparpared and the performance-related were studied. As the compatibility of the carbonfiber and epoxy resin is poor, so the surface of the carbon fiber were treated,then weprepared the treated carbon fiber epoxy composites, the change of mechanicalproperties and the influence of content of carbon fiber on mechanical properties,thermal expansion coefficient and electrical conductivity were also tested. Later on,graphene modified carbon fiber/epoxy composites were obtained and we investigatedthe influence of modified graphene on its interfacial properties,compressive propertiesand electrical conductivity.The studies showed that after the surface oxidation treatment of carbon fiber, themechanical properties of carbon fiber reinforced epoxy resin composite had beengreatly improved compared to pure epoxy matrix. When the volume fraction ofcarbon fiber was15%, the tensile strength of EP/CF composites reached a maximum,156.90%higher than pure epoxy system; When the volume fraction of carbon fiberwas25%, the compressive strength of EP/CF composites reached a maximum,116.73%higher than pure epoxy system; With the increase of carbon fiber volume content, themechanical properties of carbon fiber reinforced by epoxy composites likes a parabola.When the carbon fiber volume content was the same, the mechanical properties ofcarbon fiber/epoxy composites that after the carbon fiber surface treatment werebetter than untreated composite, in which the largest tensile strength was23.37%higher as well as the maximum compressive strength was11.73%higher.With the increasing of carbon fiber content, the thermal expansion coefficient ofcarbon fiber reinforced epoxy composites liked a wave, when the temperature wasless than Tgand the volume fraction of carbon fiber was10%, the CET of EP/CF composites reached a minimum75.22%lower than pure epoxy. The resistivity ofcomposites would change along with carbon fibers volume content, in the surface thatundergo oxidation treatment, when the volume content reached30%, the resistivitywas lowest, conductivity performance was the best.After adding graphene that grafted with silane coupling agent KH-570, theresults showed that, the mechanical properties of the composites were higher thanboth the pure epoxy system and the adding unmodified graphene system, thecompressive strength was increased by4.6%, the compressive modulus was increasedby6.4%. After adding the graphene and graphene that grafted with silane couplingagent to the composite material, the resistivity of composite material would be lower,that is to say, it had a better conductivity.