Surface Modification Of Carbon Fiber By Graphene Oxide And Properties Of Resin Matrix Composites

In this paper,graphene oxide(GO)aqueous suspension was prepaed by modified Hummers method.Carbon fiber(CF)surface was decorated by GO using the epoxy resin emulsion sizing agent,Pickering emulsion sizing agent,water-soluble epoxy resin sizing agent and physical deposition methods for improving CF and CF reinforced composites properties.The prepared GO sheets with different size distributions separated by a centrifugation method were directly dispersed in epoxy emulsion sizing agent respectively and then coated CF.The results showed that a nonuniform distribution of the large-sized GO(GOl)sheets were lapped on CF surface resulting in the worse handling characteristics.The small-sized GO(GOs)sheets were uniformly leaned on CF,which resulted in the better handling characteristics.The interlaminar shear strength of the GOs-CF reinforced composite could reach the maximum value(47.5 MPa),increasing by 14.9%,21.8% and 39.5% respectively,compared with that of GOl-CF,GO0-CF and desized CF reinforced epoxy resin composites.Epoxy resin as the primary film former,GO and surfactants as the mixed emulsifiers system,the Pickering emulsion sizing agent was successfully prepared through phase inversion emulsification method.The results showed that the optimal Pickering emulsion was obtained when the mass ratio of octylphenol ethoxylate,sorbitan monooleate and sodi?m dodecyl benzene sulfonate was 65:25:10,mass ratio of emulsifiers was 5 %,mass ratio of the GOs was 0.3 %,pH was 6 and shear rate was 8500 r/min.There existed a layer of sizing agent film with GO sheets uniformly on the CF surface after the CF was sized by the prepared Pickering emulsion.The interlaminar shear strength of the composite reached about 44.67 MPa,achieving 11.26% and 31.19% improvement compared with the common epoxy emulsion sizing agent sized CF and disized CF reinforced composites.Its fracture section was compact and had the lesser fiber extraction,which indicated that the interfacial bonding was improvement greatly.The water-soluble epoxy resin sizing agent was prepared via the ring-opening reaction between diethanolamine and epoxy resin.It was mixed with GO to size CF and then prepared CF reinforced acrylonitrile-butadiene-styrene(ABS)composites.The influences of thedifferent contents of GO on CF and CF/ABS composites were explored.The results showed that the GO could homogeneously cover the CF surface.It had the higher single tensile strength.The interlaminar shear strength of GO5-CF/ABS composite obtained the maximum value(30.57 MPa)about 22.6% improvement compared with that of the without GO modification CF/ABS composite.The GO coated short CF(SCF)was prepared by physical absorption method.The SCF reinforced polyproplene(PP)composite was obtained via the extrusion compounding and injection molding techniques.The results showed that GO mass ratio had the little impact on the flexural strength and tensile strength of GO-PP.When GO with the mass ratio of 0.5%was deposited onto the surface of SCF,it could homogeneously cover the entire SCF surface and the GO-PP impact strength was improved greatly.Furthermore,the GO0.5-SCF/GO0.5-PP composite had the highest flexural,tensile and impact strengthes among the samples with increase of 32.76%,31.07% and 94.08% as compared with SCF/PP composite,respectively.X-ray diffraction results showed that the GO added into PP matrix directly had the little effect on PP but the GO on SCF surface could act as a ?-nucleating agent for PP crystallization.Differentials scanning calorimeter showed that GO0.5-SCF/GO0.5-PP composite had the highest crystallization and melting temperature.