The Surface Modification Of Carbon Fiber By Cationic Photopolymerization And Preparation Of Composite From Modified Carbon Fiber

Carbon fibers(CFs),with its high strength,modulus,low density,excellent thermal stability and remarkable chemical resistance,mostly are used as reinforced materials.The mechanical properties of carbon fiber reinforced polymer(CFRP)mostly depend on the interface between carbon fiber surface and resin matrix.Carbon fibers have large fraction of graphitic carbon,which makes the surface of carbon fiber less reactive,non-polar,low surface energy and poor wettability.Most reports on surface modification of carbon fibers focused on the surface grafting and electrochemical polymerization.The advantage of these two methods is no harm to carbon fiber itself.However,for the most reported electrochemical polymerization system,conductive polymers were used and considerable solvent and electrolyte were added in the system.In this study,cationic photopolymerization system was introduced in carbon fiber surface modification.1,4-Butanediol diglycidyl ether(BDE)and tri(ethylene glycol)divinyl ether(DVE-3)were electrochemically polymerized on carbon fiber(CFs)to improve the surface properties of CFs.Here,BDE and DVE-3 played the roles as both polymerization monomers and solvent,and cationic photoinitiator played the role as the electrolyte to increase the conductivity and the initiator to initiate the electronical polymerization,which made extra solvent and electrolyte solution unnecessary.In this study,how the following factors,pretreatment of carbon fiber,the content of the photoinitiator,distance between two electrodes,electrochemical polymerization time and voltage,affect the electronical polymerization were investigated.Fourier transform infrared spectroscopy(FTIR),X-ray photoelectron spectroscopy(XPS),Scanning electron microscopy(SEM)and thermogravimetry analysis(TGA)testing indicated that g(BDE)and g(DVE-3)were polymerized on the surface of the carbon fiber,and the polymerization occurred from the surface of CFs.Thus,the polymer was adhered on the carbon fiber strongly.By this modification method,the adhesion between carbon fiber and epoxy resin matrix improved significantly,which caused the Interlaminar shear strength(ILSS)of BDE/CFs-epoxy resin composites(23.18 MPa)and DVE-3/CFs-epoxy resin composites(25.55 MPa)to be improved by 46.98%and 62.02%,respectively,comparing with the Raw-CFs/epoxy resin composites(15.77 MPa),and the tensile strength of BDE/CFs-epoxy resin composites(4.69 GPa)and DVE-3/CFs-epoxy resin composites(4.91 GPa)to be improved by 11.40%and 16.62%comparing with the Raw-CFs/epoxy resin composites(4.21 GPa).In addition,the color carbon fiber was successfully fabricated,which provided the approach for preparing color CFs in a rapid,effective and environmentally friendly way.