纳米复合材料-英文版-01.pdf

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1、2011/2/71Introduction ofIntroduction of Nanotechnology&Polymer Nanocomposites1MECH548Department of Mechanical EngineeringHong Kong University of Science&TechnologyOutline?Definition of Nanotechnology and Nanocompositesf C?Fundamentals of Composites Technology?The Benefits of Developing Polymer Nanoc

2、omposites?The Difference between Nanocomposites and Traditional Filler Enhanced Polymers?The Structure and Classification of Polymer2?The Structure and Classification of Polymer Nanocomposites?The History and Major Progress over the Past One and Half Decades 2011/2/72March 3,2004-Mineral fillers,met

3、als,and fibers have been added to thermoplastics and thermosets for decades to form composites.Cd ttithithbf idWorldwide Polymer Nanocomposites Market to Exceed$211 Million by 2008Composite News Supersite:http:/ to neat resins,these composites have a number of improved properties including tensile s

4、trength,heat distortion temperature,and modulus.Thus for structural applications,composites have become very popular and are sold in billion-pound quantities.These filled thermoplastics are even sold in larger volumes than neat thermoplastics.Furthermore,the volume of fillers sold is roughly equal t

5、o the volume of thermoplastic resin sold.More recently,advances in synthetic techniques and the ability to characterize materials readily on an3techniques and the ability to characterize materials readily on an atomic scale has led to interest in nanometer sized materials.These nanometer-sized grain

6、s,fibers,and plates have dramatically increased surface area compared to their conventionally sized counterparts.Polymer nanocomposites(thermoplastics and thermosets)combine these two concepts of increased surface area and synergies between fillers and matrices.Polymer Nanocomposite market to grow w

7、ell globally,particularly in USAhttp:/ 2011,nanocomposite demand will reach 150,000 tpa(tonnes per annum)in USA as per Freedonia.Growth will be fueled by declining prices of nanomaterials and composites,as production levels increase and technical issues concerning the dispersion of nanoadditives in

8、the compounds are overcome.By 2025,it is expected that nanocomposites will be a US$9 bln market,with volumes nearing 5 mln tons.While thermoplastics currently comprise virtually all demand for nanocomposites,compounds based on thermoset resins will eventually become a substantial part of the market

9、constituting 20%of demand in 2025nanocomposites based onsubstantial part of the market,constituting 20%of demand in 2025nanocomposites based on commodity plastics,such as polypropylene,polyethylene and PVC will dominate the market.Among thermosets,nanocomposites will make the strongest impact as enh

10、ancements for reinforced polyester and epoxy compounds.Packaging and motor vehicles,two key early markets for nanocomposites,will account for nearly 50%of total demand in 2011,and 40%of demand in 2020.However,by 2025,electrical and electronics applications will gain in prominence,as nanotube-based c

11、omposites will penetrate a sizable portion of the market as a substitute for other conductive materials.Construction will emerge as a significant market as nanocomposites begin to replace fiber-reinforced plastics in a number of applications.Nanocomposites are expected to penetrate a number of key p

12、ackaging applications,including pppy pg gpp,gsoft drinks,beer,food,pharmaceuticals and electronics,driven by the improved barrier,strength and conductive properties that they offer.In motor vehicles,automotive manufacturers are increasingly turning to nanocomposites in an effort to replace higher-pr

13、iced materials,increase production speed of parts and reduce motor vehicle weight in a number of exterior,interior and underhood applications.Major players:3M ESPE,Arkema Group,BASF AG,Cabot Corporation,Cyclics Corporation,DSM Somos,Du Pont(E.I)De Nemours&Company,Elementis Specialties Inc,eSpin Tech

14、nologies Inc.,Evonik Degussa GmbH,Foster Corporation,Hybrid Plastics,Industrial Nanotech Inc,Inframat Corporation,InMat Inc,Nanocor Incorporated,Nanodynamics Inc,Nanoledge SA,Nanophase Technologies Corporation,Nanova LLC,Powdermet Inc,Showa Denko K.K.,Rockwood Additives Ltd,TNO,Unitika Ltd,and Zyvex

15、2011/2/73Definition of Nanotechnology Nanotechnology is the understanding dtlfttt diifand control of matter at dimensions of roughly 1 100 nm.At this level,the physical,chemical,and biological properties of materials differ in fundamental and valuable5differ in fundamental and valuable ways from ind

16、ividual atoms&molecules or bulk matter.Differences of Nanometer-scale Structures Different fundamental properties,such asproperties,such as melting temperature,magnetic properties,charge capacity,color,etc.Same chemicalcompositions6compositions.New materials for novel,high-performance products and t

17、echnologies.2011/2/74Nanotechnology-related R&D Activities in 2004 Under the survey of approx.600 ppcompanies involved in the nanotechnology-related business,it was reported that IBM,Intel and LOreal had filed 7the largest amounts of related patents.Source:EmTech Research 2005Nanoparticles&Polymer N

18、anocomposites Nanoparticles:at least one dimension in the range of 1 to 100nm Jordan etin the range of 1 to 100nm Jordan et.Al,2004.Polymer nanocomposites(PNC):polymers with small quantities(less than 5%by weight)of nano-sized reinforcements having high aspect8reinforcements having high aspect ratio

19、s(L/h 300)Denault&Labrecque,2004.2011/2/75Questions Why are composite materialsWhy are composite materials necessary?How/what are composites made of?Where are composites usefully applied?9Why Composites?A composite is a mixture of two or more phases(materials).()A better or unique combination of pro

20、perties is realized when different materials(or phases)are combined The primary needs for all the advanced it10composites are:light weight,higher operating temperatures,greater stiffness,higher reliability and affordability.2011/2/76What are Composites Made of?Human learns from mother nature tomothe

21、r nature to develop new composite materials Natural Composites:wood and bamboo,shells,bones,muscles,other tissues11muscles,other tissues and natural fibres(silk,wool,cotton,jute,sisal)Four Classes of Materials Composites can be produced using three classes of materials:polymers Metals andclasses of

22、materials:polymers,Metals and Ceramics 122011/2/77DefinitionTwo phase composite:Matrixis the continuous Matrixis the continuous phase and surrounds the reinforcements Reinforcementis the dispersed phase,which normally bears the majority of stress 13ReinforcementsA reinforcement is the strong,stiff i

23、ntegral component which is incorporated into the matrix toincorporated into the matrix to achieve desired properties The term reinforcement implies some property enhancement?Different types of reinforcements:?Fibres or Filaments:continuous fibres,discontinuous fibres,whiskers.14?Particulates reinfor

24、cementsmay be of any shape,ranging from irregular to spherical,plate-like or needle-like,nanoparticles.They have a low ductility.2011/2/78Matrix Made from Metal,polymer or ceramic Continuous phaseSdtilitidibl Some ductility is desirable Functions Binds the reinforcements(fibers/particulates)together

25、 Mechanically supporting the reinforcements Load transfer to the reinforcements Protect the reinforcements from surface damage15 Protect the reinforcements from surface damage due to abrasion or chemical attacks High bonding strength between fiber and matrix is importantClassification of Composites1

26、6Continuous,aligned fibre composites2011/2/7917Short fibre composites LaminatesParticulate reinforced composites 18honeycombadhesive layerface sheetSandwich panels 2011/2/710Particulate Reinforced Composites The particulates are harder and stiffer than the e pa t cu ates a ea de a d ste t at ematrix

27、 material The particulates are of macro-,micro-or nano-scopic scale The improvement of mechanical behaviour depends on the interface bonding 19 Examples:Silica-epoxy composites(electronic moulding compound)Cermets(WC or TiC reinforced cobalt or nickel)Concrete(aggregate-gravel and sand-reinforced ce

28、ment)SiC or Al2O3particle reinforced Al matrix.Fibre-reinforced Composites(FRC)Mechanical properties of FRC depend onon Fiber properties Degree to which an applied load is transmitted to the fibers by the matrix phase:good interfacial bond between fibdt ii20fiber and matrix is necessary Design goals

29、 of FRPs High specific strength and/or stiffness2011/2/711Polymer-Matrix Composites(PMCs)Consists of a polymer resin as the matrix Being used in the greatest diversity and largest quantitiesA.Glass fiber-reinforced polymer composites(GFRPs)Produced in the largest quantitiesB.Carbon fiber-reinforced

30、polymer composites(CFRPs)21 High performance compositesC.Aramid fiber-reinforced polymer composites(AFRPs)High strength,high modulus&high impact resistance compositesPolymer Matrix Materials Thermosets A thermoset may not be re-melted once cured(cross-linked).(cross linked).Polyester&vinylester resi

31、ns:low cost applications.Epoxies:aerospace application due to the better resistant against moisture and mechanical properties.Thlti22 Thermoplastics May be melted or softened at an elevated temperature repeatedly.Higher temperature applications using polypropylene(PP),polyimide(PI),Nylon.2011/2/712G

32、lass Fiber-Reinforced Polymer(GFRP)Glass fibres(or Fibre Glass):Easy to manufacture,chemical resistanceGlass fibre surface is coated with a thin polymer layer,i.e.“size”,to protect the fibre surface from damageGFRPs use temperature is limited below 200 C due to polymer matrix23polymer matrix Major a

33、pplications of GFRPs Automotive,marine vehicle bodies,pipes,storage containers,industrial flooringManufacturing of Glass Fibres Carbon Fiber-Reinforced Polymer(CFRP)Carbon fibers:High specific modulus and specific strength even at high temperatureggpGood physical and mechanical propertiesExpensive m

34、anufacturing processesOrganic precursors:rayon,polyacrylonitrile(PAN)and pitchDiameter:4 to 10 m,coated with epoxy size to improve adhesion with t i24matrixMajor Applications of CFRPs:aircraft structural components,sporting goods,rocket motor cases,pressure vessels,etc.2011/2/713Aramid-Fiber-Reinfor

35、ced Polymer(AFRP)Aramid fibers(Kevlar)Thermoplastic material:poly-paraphenylene terephthalamide(PPTA)High tensile properties and weak compressive properties.Mechanically stable between 200 and 200CChemically weak to degradation by strong acids and bases.Major applications of AFRPsBullet-proof vests,

36、sporting goods,ropes,missile cases,pressure vessels,automobile brakes and clutch linings 25Typical Properties of Continuous and Aligned GFRP,CFRP and AFRP262011/2/714 Aerospace:wings,fuselages,landing gears,rudders/elevators rotor blades satelliteApplications of Polymer matrix Compositesrudders/elev

37、ators,rotor blades,satellite structure Automobile:body panels and frames,bumpers,leafsprings,drive shafts,seat housing,tyres and other ground transportation vehicles(bullet train).Marine(e g Catamaran):boat hulls decks27 Marine(e.g.Catamaran):boat hulls,decks,masts,propeller shafts,wind surfer Chemi

38、cal plants:process pipes,tanks,pressure vessels,oil field structures Sporting goods:tennis rackets,golf clubs,hockey sticks,fishing rods,baseball bats,bicycles,skis,canoes,bow,swimming pools Construction:Bridge decks,repair of concrete decks,bridges,columns;FRP re-bars Biomedical:teeth,filler,bone r

39、eplacements,artificial limbs Electrical:Panels,switch gear,insulators,moulding compounds conductive adhesives28moulding compounds,conductive adhesives Others:wind turbine blades,musical instruments,umbrellas,pens,lighters2011/2/715Applications of Polymer matrix Composites29Airbus A380 Largest passen

40、ger aircraftMade of largest amount of carbon fibersStealth AircraftsExtensive use of carbon fibre composites to make them undetectable by radars B-2 bomber Boeing 777 WorldlinerLongest-range passenger aircraft30SR-71 Blackbird B-2 bomber 2011/2/716Sporting Goods 31Automobile Body Components322011/2/

41、717Electronics Applications33Hybrid Nanocomposite Golf Shaft AccuFLEX Golfs Nano Composite technology enhancement increases the surface area of our shafts thereby creating a tighter molecular structure.This means that shafts that are enhanced with AccuFLEX Golfs Nano Composite technology have less v

42、oids in34technology have less voids in the fiber,tighter tolerances and can feature lighter weight with more fiber density.Nano Composite technology shafts are also stronger,have faster recovery with less shaft deformation while transmitting better feel.2011/2/718Babolak Tennis RacketBabolak nanorac

43、het is made from graphite fabrics and35from graphite fabrics and carbon nanotubesBabolak nanorachet is five times stiffer than graphite racketsIt is selling at US$180-250 Super-strong,Super-light Bicycle Frames CNT COMPOSITE Easton is the first manufacturer to incorporate real nanotechnology in bicy

44、cle components.Carbon t b(CNT)36nanotubes(CNT)strengthen the resin matrix at the molecular level2011/2/719Other Sporting Goods Other sporting goods containing carboncontaining carbon nanotubes:those traditionally made with graphite fibre composites Hockey sticks HelmetsRacing yacht masts37 Racing ya

45、cht masts Baseball batsSuper-hard Bowling Balls by NanodesuABS Nanodesu X Super-wear resistant and abrasion resistant coatingabrasion-resistant coatingCoating Material:FULLERENE NANO CARBON C-60Lane Condition:Heavy OilBall Color:GreyBall Finish:PolishedPrice:US$159.98(High quality normal ABS-38(High

46、 quality normal ABS-acrylonitrile butadiene styrene-balls costs about US$40-50)2011/2/720Organoclay-Polymer NanocompositesOrganoclay reinforced EVOH,PET,PCL matrix nanocomposites with excellent gas/moisture barrier g/characteristicsIncorporation of proactive antimicrobial capabilities for enhanced s

47、helf life(use-by-date)of the contentsApplication of nanocomposite films for various food and beverage packages39beverage packages Metal-Matrix Composites(MMC)The matrix is more ductile than the reinforcements The reinforcement may improve specific strength/stiffness,abrasion resistance,i tthldti itP

48、ressurecreep resistance,thermal conductivity and dimensional stability of the overall compositesAdvantages over PMCHigher operating temperaturesNon-flammabilityGreater resistance to degradation by organic fluidsDisadvantages40gExpensive due to high process temperature,e.g.solidus temperature of the

49、metal.Higher density due to difficult to make the composites with low volume fraction of filler since the filler naturally contact one another.(Then,how to fabricate low filler volume fraction in MMC?)Preform:reinforcement,binder (can be polymer(e.g.acrylic),ceramic(e.g.silica),or the matrix metal i

50、tself.2011/2/721Matrix materials Superalloy(e.g.single crystal Ni based alloys),Al,Mg,Ti,CuReinforcements C,SiC,B,Al2O3fibers,SiC,Al2O3particlesApplications:Automobile engine componentsAerospace structures(e.g.space shuttle orbiter,f41telescope made from B or C fibers-Al matrix composites)Turbine en