碳纤维增强复合材料ppt课件.pptx

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1、RESEARCH AND TREATMENT OF THE SURFACE OF CARBON FIBER IN CARBON FIBER REINFORCED COMPOSITEScontentsPART 01PART 01PART PART 0202PART PART 0303PART PART 0404PART PART 0505IntroductionIntroductionCF interfaceCF interfaceArticle Article oneoneArticle twoArticle twoConclusionsConclusions01PART ONEIntrodu

2、ction0101CARBON FIBERWhat is Carbon Fiber?Carbon fiber is a fibrous carbon compound that carbonized by high temperature (1500 ) in an inert atmosphere of an organic or low molecular hydrocarbon gas. The carbon content of the compound is more than 90%0202CFRCWhat is Carbon fiber reinforced composites

3、 ?CFRC is a kind of structural material made of carbon fiber with resin, metal or ceramics. Excellent tensile strength, high stiffness, light weight and great thermal resistance make carbon fiber reinforced composites an ideal structural material.0202CFRCINTERFACR:Interface is an intermediate phase

4、between the reinforcing phase and the matrix phase, which is the bridge between the reinforcing phase and the matrix, as well as the transmitter of stress and other information.The properties of carbon fiber composites are determined by three main components: fiber, matrix and interface layer.02PART

5、 TWOCF interface0101INTERFACEThe property of CF composites mainly depends on the quality of the interface between the matrix and the reinforcement, which determined the way of the loads transfer from the matrix to the carbon fiber.The improvement of the interfacial adhesion strength between the carb

6、on fiber and polymer matrix is a key factor to improve mechanics performance of composite materials. 0202CHALLENGE OF THE INTERFACEComposite interface phaseThe surface of carbon fiber only contains elements of C, H and O.Hydroxyl and carbonyl group on carbon fiber without surface treatment only acco

7、unt for about 16.5% There are just too little amount of polar groups on the surface which makes it challenging to creat the bonding between carbon fiber and the matrix resin.0303METHODS TO ENHANCE THE ADHESIONFirst, prevent the formation of weak interface layer. the impurities attached to the mold r

8、elease agent; the aging of the interface layer formed when the oxide layer,hydrate layer;the substrate is not fully infiltrated and bound by the air layer;.How to increase the adhesion between CF and resin?0303METHODS TO ENHANCE THE ADHESIONSecond, the surface morphology is suitable for bonding. The

9、 increase of surface roughness is beneficial to the mechanical fitting of carbon fiber and matrix resin, and to enhance the effect of anchoring.Third, improve the affinity of resin and reinforcement. The introduction of polar or reactive functional groups, and the role of the intermediate layer with

10、 resin, such as - COOH, - NH2, - OH.0303METHODS TO ENHANCE THE ADHESIONsurface treatmentoxidationNon-oxidationVapor phase oxidationLiquid phase oxidationCatalytic oxidationVapor deposition methodElectro polymerizationWhisker growth methodPlasma method03PART THREEArticle one0101GRAFTINGGrafting of mi

11、cro-molecules or polymers onto the carbon fiber surface can yield a controlled, ordered and active structure, which has can be an effective modification method.D400,as a traditional cross-linker of epoxy, contains two active primary amine groups located on secondary carbon atoms at each end of an al

12、iphatic polyether chain . And flexible polyether chain contributes to stress transfer between carbon fiber and epoxy.0202PROCESSES增强因子重复性CFHNO3（80、4h）ACFHATU was used as condensing agentWasheddried in a vacuum furnace ACF/D400carbon fiber reinforced epoxycompositeswashed several times，dried under va

13、cuumD400（90、4h）epoxy0303RESULTS AND DISCUSSIONThe following depicts the surface morphologies and roughness of the carbon fibers.Surface of untreated CF is smooth，after acid treatment the smooth surface of carbon fiber changes to be coarse due to the absorption of D400 onto carbon fiber surface.0303R

14、ESULTS AND DISCUSSIONThe wettability of carbon fiber is investigated using advancing dynamic contact angle test.After D400 grafting treatment, the contact angles decrease, while the surface energy of carbon fiber increases. The wettability of carbon fiber was increased and the change of the fiber su

15、rface free energy confirms the successful deposition of D400 on carbon fiber surface. 0303RESULTS AND DISCUSSIONIFSS was adopted to quantify the interfacial property between carbon fiber and epoxy.F-maximum load recordedd-carbon fiber diameterl-embedded lengthAfter adsorption of D400, the IFSS of CF

16、/D400 composite increases to 55.8 MPa which is attributed to improvement of surface energy. D400,which can not only react with the reactive groups on the carbon fiber surface, but also increase resin compatibility and react with the matrix system.D400 molecules have exactly and completely covered th

17、e whole surface of carbon fibers at 2 *10-4 mol/L concentration. 0303RESULTS AND DISCUSSIONThe following depicts the surface morphology of carbon fibers after debonding from the epoxy matrixBefore grafting（Fig a）,the debonding between carbon fiber and epoxy is interfacial failure. After adsorbed D40

18、0, more epoxy debris adhere on the carbon fiber after debonding , due to the strong covalent bonds formed between amino and carboxyl groups. As D400 concentration goes up, there is more remaining epoxy resin.0303RESULTS AND DISCUSSIONIt can be seen that the tensile strength of all D400 treated carbo

19、n fibers are a little higher than that of the untreated CF (4.73 GPa). The tensile strength of D400 grafted carbon fiber increased slightly with the increase of concentrationThe results imply that D400 grafting can not only make up the tensile strength losses due to the etching effect during the aci

20、d treatment, but also mildly enhance tensile strength of carbon fiber.Tensile strength of single fiber was measured by tensile test.04PART FOURArticle two0101IntroductionA two-step method for high efficient and continuous carbon fiber treatment with enhanced fiber strength and interfacial adhesionAl

21、though numerous surface treatment methods have been proposed to improve the smooth and inert surface of carbon fibers, most of them are usually accompanied by the damage of fiber strength0101IntroductionA TWO-STEP METHODplasma treating PyC coatingSTEP ONESTEP TWO0101IntroductionCarbon coating which

22、has similar chemical composition and structure with carbon fibers is considered as another potential surface protective material for carbon fibers CARBON COATING PYROLYTIC CARBON(PYC) The alkane or carbide were deposited on the surface of carbon fiber after pyrolysis to form film with a high tempera

23、ture0101IntroductionPYC FROM ETHANOL pyrolytic carbon (PyC) using ethanol precursor has attracted much attention because the hydroxyl group in ethanol can make the PyC structure dense and controllable. PyC with the thickness of several tens of nanometers could effectively heal the flaws on the carbo

24、n fibers, and increase their tensile strength PYC FOR CARBON FIBERSurfacePyC coating0101IntroductionDue to weak boundary layer and the pollutants on carbon fiber surface, the binding strength between PyC and CF is weak which usually results in debonding between these two phases when the composites a

25、re under loading. CHALLENGE OF PYCPLASMA TECHNOLOGY Weak boundary layer and the pollutants reacts with the plasma and were etched to form a volatile substance.pollutantsplasmasurface0101IntroductionA TWO-STEP METHODplasma treating PyC coatingRemove the weak boundary layer and the pollutants on the s

26、urface of the CFEnhance the roughness and increase the adhesion between the CF and matrix0202measurementMorphologies SEMThe surface roughness,thickness and modulus of PyC coating AFM surface composition and surface energy XPS mechanical property universal testing machine (Atomic Force Microscope)(X-

27、ray photoelectron spectroscopy)0303Results-morphologies there are a few narrow grooves distributing along the untreated fiber axial direction.(a) Untreated fibers (b) plasma treated fibers the surface becomes rougher and the grooves become more obvious numerous particles of several nanometers cover

28、the wholefiber (c) PyC coated fibers 0303Results-surface composition The removal of the weak boundary lay, oxides and pollutants by no- reactive helium plasma etching. The amounts of carbon and nitrogen increase slightly and oxygen content drops 0303Results-surface composition Nitrogen that derives

29、from the polyacrylonitrile precursor is not detectedIt implies that the carbon fiber is totally covered by PyC0303Results-surface composition their surface composition is quite different from those of fibers covered with PyC. It can be attributed to the oxidation and the oxygen-containing groups in

30、epoxy sizing 0303Results-surface energy The wettability of carbon fibers influences the interfacial adhesion of the composites. The higher surface energy, no matter its polar or dispersion component, can lead to better wettability of the fibers by the resin and stronger interfacial adhesion in the c

31、omposites 0303Results-surface energy the dispersion component（d） shows a slight increase the polar component（p） of surface energy reduces slightly. the increased surface roughness 0303Results-surface energy As the reason of the rough surface and different graphite structure, the surface energy of th

32、e fiber after coated with PyC increases significantly, especially for the dispersion component 0303Results-surface energy For the commercial fibers, the surface energy is much higher than that of the PyC coated fibers, which is due to the numerous oxygen groups on fiber surface. 0303Results-mechanic

33、al propertythe fiber strength is not obviously affected after plasma etching the plasma only takes action in the depth of several nanometers 0303Results-mechanical propertythe fiber strength increases dramatically from 3.02 to 3.43 GPa and the data dispersion is the lowest among the five group sampl

34、es the healing effect of the uniform PyC on the flaws of the fiber surface. 0303Results-mechanical propertyAfter the commercial anodic oxidation treatment,the fiber strength decreases slightly to 2.87 GPa. 0303Results-mechanical propertyThe strength increases again to 3.20 GPa,which means the flaws

35、created by anodic oxidation are healed. 0303Results-mechanical propertyILSS was used to assess the effect of PyC coating on the interfacial adhesion of the composites. 0303Results-mechanical propertyThe ILSS of the PyC coated faber increases from 70.1 to 85.7 MPa PyC coating increase the fiber surfa

36、ce roughness which could supply strong mechanical interlocking;Surface energy which could make polymer wet the fiber surface easily; 0404Brief summarythe plasma etching is important, which can remove most of the amorphous carbon, weak boundary layer and pollutants on fiber surface. ordered and dense

37、 graphite structure is retained, and can act as growing sites and induce the nucleation of PyC during the pyrolysis process, which would enhance the boding strength between fibers and PyC coatings. A TWO-STEP METHODplasma treating PyC coating05PART FIVEConclusions0101ConclusionsTREATMENT OF CFGRAFTI

38、NGAdvantages：Diversity of Grafting monomerSimple polymerization conditionsDrawbacks：Inhomogeneity of GraftingComplicated processes0101ConclusionsTREATMENT OF CFA TWO-STEP METHOD plasma treating PyC coatingpollutantsplasmaAdvantages：Reserve the carbon fibers mechanical propertyDrawbacks：This method i

39、s still on testing stage 0101ConclusionsAlthough there are many methods for carbon fiber to enhance its mechanical property and adhesionInferiorities existing：The methods we used contain many complex processesHave a long path to commercialization Difficult to control the condition of the reactionDevelopment of CF in domestic have a gap with others THANKS