SBS Grafted Carbon Nanotubes Reinforced And Toughened Carbon Fiber Epoxy Resin Composites

Carbon fiber reinforced resin(CFRP)composites have attracted extensive attention in the field of high performance lightweight materials due to their ultra-high specific modulus,specific strength and excellent mechanical properties.However,CFRP composites also have shortcomings such as low toughness,poor interfacial properties,and easy peeling between layers,which limits its application range.In order to solve the above problems,styrene-butadiene-styrene elastomer grafted multi-walled carbon nanotubes(SBS-g-MWNTs)were selected as reinforcing materials to be added into carbon fiber/epoxy resin(CF/EP)to fabricate SBS-g-MWNTs/CF/EP three-phase composite laminates for improving its overall mechanical properties in this paper.The chemical structure changes of MWNTs in various stages of the modification process and morphology were characterized by Fourier transform infrared spectroscopy(FT-IR),X-ray photoelectron spectroscopy(XPS),Raman spectroscopy(Raman),thermogravimetric analysis(TGA),scanning electron microscopy(SEM),and transmission electron microscopy(TEM).We also mainly studied the effects of SBS-g-MWNTs on the mechanical and thermal properties of CF/EP composites and interface enhancement mechanism.The mechanical results indicate that the mechanical properties of SBS-g-MWNTs/CF/EP composites can be greatly improved when the SBS-g-MWNTs loading reach 0.50 wt.%.The tensile strength,flexural strength,impact strength and interfacial shear strength(ILSS)were increased by 21.6%,85.5%,90.2% and 99.7%,respectively.The TGA and Dynamic Mechanical Analysis(DMA)testing results of the composites show that the CF/EP with SBS-g-MWNTs exhibit higher thermal stability and heat resistance than the pure CF/EP.The fracture morphology(SEM)of SBS-g-MWNTs/CF/EP composites show that the grafting of flexible SBS on rigid MWNTs can not only effectively improve the dispersion,but also strengthen the interfacial adhesion between epoxy resin(EP)matrix and carbon fiber(CF).This is mainly due to the existence of low modulus flexible interface layer in the overall structure of the material,which can buffer the applied load and absorb energy,and finally achieve the effect of strengthening and toughening the SBS-g-MWNTs/CF/EP three-phase composites.