The Study Of Modified The Surface Of Carbon Fiber Using Graphene And Interfacial Stress Strength Of Their Resin Matrix Composites

Nowadays,carbon fiber reinforced resin matrix composites have attracted much attention due to its high strength,stiffness and toughness.Their whole properties usually decided by 3 elements as carbon fiber,epoxy resin and their interfacial strength.Among them,interfacial strength,as a link of carbon fiber and epoxy resin,determine the strength of composites radically.Good interfacial interaction can effectively disperse and pass on the load the epoxy resin got,which can make full use of reinforced function of carbon fiber.However,carbon fiber is essentially microcrystalline graphite materials which have smooth surface,strong chemical inertness similar to carbon and poor wettability.There is weak interfacial reaction after combining with resin matrix,which influences the overall excellent performance of carbon fiber resin matrix composites.Therefore,it is important and hot about how to deal with the surface of carbon fiber and improve the wettability.The high-profile graphene has a series of excellent performance,such as large specific surface area and excellent mechanical properties,etc.These features make it possible to improve the contact area between fibers and resin matrix and to pass load effectively.In this paper,the ordered 3D stacked multilayer graphene sheets,also called graphene nanowalls(GNWs),have been directly grown vertically on the surface of silicon wafer and carbon fibers using chemical vapor depositon system.Some properties have been researched.There is a layer of amorphous carbon film under GNWs,which indicate that GNWs are not isolated.GNWs can change the wettability of substrate,and finally presents oil-wet and hydrophobic.Besides,it has excellent light absorption performance These GNWs have not only a stable and rigid porous structure,large surface area,excellent physical and chemical stability and high conductivity but also open boundary structure,high edge density and high degree of oxidation.So GNWs can be fully infiltrates by resin matrix,forming a “tenon-mortise” mechanical interlocking structure between the carbon fiber and matrix and increasing interfacial stress strength(IFSS).On the other hand,there are very strong ?-? stacking between carbon fiber and GNWs,which pass load effectively.Secondly,epoxy resin curing condition was studied,whose curing process is confirmed as 60?/1h+88?/1h+115?/1h.After combining epoxy resin and carbon fiber with GNWs,single-fiber fragmentation test was used to research the influence from GNWs to IFSS of carbon fiber/epoxy resin according to theoretical analysis and laboratory conditions.The interface between epoxy and carbon fiber fails when the interface of composites destroyed from the SEM image.It also indicate that the interface between GNWs and carbon fiber is perfect.The results showed that the interfacial shear strength of the composites was improved by 173% in the presence of GNWs at the fiber/matrix interface from single-fiber fragmentation test.Finally,GNWs with different structure were deposited on the surface of carbon fibers.We studied the law from structure of GNWs to IFSS.The results indicate that the mean GNWs size density increase nonlinearly with linear increase of GNWs thickness.It is quadratic non-linear relationship from fitting equation.Besides,IFSS of carbon fiber increased first and then stay stable along with the increase of GNWs thickness and along with mean GNWs size density.