The Construction Of Carbon Fiber Surface Loaded GO/CNTs System And Study On Their Interfacial Properties

Carbon fiber composites are widely used in several fields.Examples include aerospace,national defense construction,construction materials etc due to their light weight,high modulus,good corrosion proof,and excellent designability.However,the surface of carbon fiber is inert with very limited polar functional groups,which considerably influences it bonding to resin matrix.Generally,the interfacial modification of carbon fiber?CF?is a primordial step before preparation of CF based composite materials.The nano particles immobilization on carbon fiber the most common method for CF interface modification.In order to improve the interfacial properties of carbon fiber composites,carbon nanoparticle was loaded by electrophoretic deposition in this earlier project.To change the loading morphology of graphene oxide?GO?,we adjust the electrophoretic deposition voltage.To regulate the length of CNTs,the acidification time of carbon nanotubes?CNTs?changed.The results showed that small-size GO was incorporated on the surface of carbon fiber at low pressure.Large-scale GO appeared on CF interface at high pressure with warping,which increases the surface roughness of carbon fiber.The interfacial shear strength?IFSS?of CF/GO composites increased by 38.3%.Acidification time of CNTs can effectively change the length of CNTs.the length of CNTs increase with the decreasing of acidification time,the entanglement is easy to occur,which increases the thickness of the transition layer,the IFSS of composites increases by 31.1%.The longer is the acidification time,the shorter is the CNTs.This would weaken the interfacial properties of composites.The surface modification of carbon fibers by CNTs/GO was successfully performed via electrophoretic deposition,while the interfacial properties of carbon fiber composites was not ideal because of the weak conductivity of CF/CNTs composites,the destruction of carbon fiber under high voltage and the multiple-electrophoretic depositions.In this conditions the IFSS only increased by 18.7%.Considering that electrophoretic deposition of CNTs/GO is difficult to synergistically exert the advantages of carbon nanoparticles,we attempted to load CNTs/GO onto carbon fiber by chemical grafting.The results show that the carbon nanoparticles can be successfully loaded onto the surface of the carbon fiber.The effect of the CNTs/GO by chemical grafting modification is better than that of the electrophoretic deposition.The interface performance of the composite improved by62.2%,however the interfacial strength of the fiber was greatly damaged due to the acidic treatment of the carbon fiber.The composites' monofilament tensile strength decreased by 13.6%.Therefore,chemical grafting is not ideal procedure for carbon fibermodification.In order to further improve the synergistic effect of carbon nanoparticles?CNTs and GO?and the advantages of physical deposition and chemical grafting.The electrophoretic deposition-chemical grafting method was adopted to modify the carbon fiber surface.Electrophoretic deposition of Ag nanoparticles on CF not only reduces the damage to the strength of the carbon fiber,but also increases the surface roughness of the carbon fiber.Grafting of amino-thiophenol?4-ATP?on the basis of CF/Ag helped in the incorporation of polar groups?-NH₂?and positioning the Ag nanoparticles into the bridges between CF and carbon nanoparticles.The results show that the cooperative immobilization of GO/CNTs improves over 80% of the interfacial performances of carbon fiber composites by.In our studies,the interfacial reinforcement mechanism of the composites was investigated by changing the size of the GO sheets and the length of the CNTs particles.The results show that the interfacial property of the carbon fiber composites is the best when the size of GO sheet is moderate and the CNTs length is the largest.