第07章-纳米技术改性

第七章纳米技术改性复合体系组合分散相的尺度大小1000nm(1μm)100~1000nm(0.1~1μm)1~100nm(0.001~0.1μm,10~1000Å)0.5~10nm(5~100Å)（1）聚合物/低分子物低分子作增容剂低分子流变改性剂外部热塑性聚合物（2）聚合物/聚合物宏观相分离型聚合物掺混物微观相分离型聚合物合金（1）分子复合物；（2）完全相容型聚合物合金（3）聚合物/填充物聚合物/填充物复合体系聚合物/填充物复合体系聚合物/超细粒子填充复合体系聚合物纳米复合体系聚合物复合体系的分类纳米概念的形成早期，石墨、炭黑中的颗粒1959年，美国物理学家RichardFeynman提出“whatwouldhappenifwecouldarrangetheatomsonebyonethewaywewantthem?”20世纪70年代康乃尔大学C.G.Granqvist&R.A.Buhrman小组气相沉积制备纳米20世纪80年代，原西德Gleiter首次制备金属纳米，提出纳米材料及其应用1981年，IBM发明AFM和STM，推动纳米技术发展20世纪80年代末期，日本丰田研究中心制得PA6/粘土纳米复合材料WhatnanocompositesareNanocompositesaremadebymixingtwoormorephase,suchasparticles,layersorfibres,whereatleastoneofthephasesisinthenanometresizerange.Becausethebuildingblocksmakingupthenanocompositesarethereforesoclosetothemolecularscale,confinementandquantumeffectsresultfromthewaythattheblocksinteract.Nanocompositesshowpropertiesnotfoundinbulkmaterials,differentiatingthemfromtypicalcompositesorfilled-polymersystems.纳米复合材料非聚合物纳米复合材料金属/金属金属/陶瓷陶瓷/陶瓷聚合物纳米复合材料有机/无机纳米复合材料聚合物/聚合物纳米复合材料聚合物基无机物基分子复合原位复合微纤/基体ClassificationofnanocompositePolymer/inorganicnanocompositesPolymernanocompositesaregenerallydefinedasthecombinationofapolymermatrixresinandinorganicparticles(particles,layersorfibres)whichhaveatleastonedimension(i.e.length,width,orthickness)inthenanometersizerange制备聚合物纳米复合材料的无机物的种类•纳米粒子(CaCO3、SiO2、TiO2、ZnO、Al2O3、Cr2O3)•纳米纤维(碳纳米管、纤维素晶须、凹凸棒土)•层状无机物Layeredhostcrystalssusceptibletointercalationbyapolymer蒙脱土的化学通式：Nax(H2O)4{(AL2~xMgx)[Si4O10](OH)2}分类：钠基蒙脱土（碱性土）钙基蒙脱土（碱土性土）天然漂白土（酸性土）蒙脱土的改性方法人工钠化改型（悬浮液法、堆场钠化法、挤压法）酸活化方法（干法活化工艺、湿法活化工艺）湿法生产工艺：包装原土破碎制浆提纯改型活化有机覆盖过滤干燥粉碎覆盖剂干法生产工艺：包装原土制浆提纯1提纯2改型活化精细钠土加热混合干燥粉碎覆盖剂Structureof2:1layeredsilicates蒙脱土的结构特征---天然的纳米结构Cation-exchangereactionbetweenthesilicateandthealkylammoniumsalt蒙脱土族矿物具有离子交换性、吸水性、膨胀性、触变性、黏结性、吸附性等特性插层剂的作用利用离子交换的原理进入蒙脱土片层之间；扩张片层间距；改善层间的微环境；使蒙脱土的内外表面由亲水性转化为疏水性；增强蒙脱土片层与聚合物分子链之间的亲和性；降低硅酸盐材料的表面能。常用的插层剂有烷基铵盐、季铵盐、吡啶类衍生物和其他阳离子型表面活性剂聚合物/层状硅酸盐纳米复合材料特点需要填料体积分数少；具有优良的热稳定性及尺寸稳定性；性价比高。PolymerlayeredNanocompositespreparationIn-situintercalationpolymerizationtointercalatethemonomerandthentakeadvantageofthehost’soxidisingpropertiestoinducepolymerizationPolymerintercalationfromsolutionPolymermeltintercalationtomixthepolymerandlayeredsilicatetogetherandthenheatthemixtureabovetheglasstransitiontemperature(softeningpoint)ofthepolymerExfoliation-adsorptionTemplatesynthesisInsituPolymerizationSchematicrepresentationofin-situpolymerization聚合物大分子溶液插层工艺示意图SchematicrepresentationofmeltintercalationMainhopperSidefeedingDevolatilizationExtrudate制备方法的改进利用共聚物制纳米复合材料（PS、PMMA）；利用聚合物催化剂制纳米复合材料（PS、PET）；利用相容剂制纳米复合材料（PP）；利用环状低聚物的开环聚合制纳米复合材料（PC）；硬质环氧树脂纳米复合材料的制备（硬质环氧树脂）。NaokiHasegawa,etal,Polymer44(2003)2933–2937anovelcompoundingprocessusingNa–montmorillonitewaterslurryforpreparingnovelnylon6/Na–montmorillonitenanocompositesNaokiHasegawa,etal,Polymer44(2003)2933–2937LayeredNanocompositestructurePLS纳米复合材料微观结构的分类表SchematicdepictingtheXRDpatternsforvarioustypesofstructuresThenewpropertiesofnanocompositesEfficientreinforcementwithminimallossofductilityandimpactstrengthIncreasethermalstabilityIncreaseflameretardantImprovedgasbarrierpropertiesImprovedionicconductivityReducedthermalexpansioncoefficientAlteredelectronicandopticalpropertiesPropertiesofNylon-6layeredsilicatenanocompositesPropertyNanocompositesNylon-6TensileModulus(GPa)TensileStrength(MPa)HeatDistortionTemp(℃)ImpactStrength(KJ/m2)WaterAdsorption(%)CoefficientThermalExpansion(x,y)2.11071602.80.516.3×10-51.169652.30.8713×10-5(a)Organoclay(wt%)dependenceofHDTofneatPLAandvariousPLACNs.(b)LoaddependenceofHDTofneatPLAandPLACN7TGAcurvesforpolystyrene,PSandthenanocompositesProposedmodelforthetorturouszigzagdiffusionpathinanexfoliatedpolymer–claynanocompositewhenusedasagasbarrierComparisonofcombustionofNylon6,6andNylon6,6nanocompositewithclayfractionof5wt.-%(Cloisite15A)atexternalfluxof35Kw/m2PP及其纳米复合材料的热释放速率对比（热通量=35kW/m2)RealpictureofbiodegradabilityofneatPLAandPLACN4recoveredfromcompostwithtime.Initialshapeofthecrystallizedsampleswas3*10*0.1cm3.Degreeofbiodegradation(i.e.CO2evolution),and(b)time-dependentchangeofmatrixMwofneatPLAandPLACN4(MEEclay=4wt%)undercompostat(58+2)ºC聚合物纳米复合材料的问题无机相分布不规则；无机相形态难控制；存在界面问题；分散方法需改进。MorphologyoflayeredsilicateKineticsofpolymermeltintercalationTwostepsfornanocompositeformation:Polymertransportedfromtheagglomerate-polymermeltinterfacetotheprimaryparticlesPolymermeltpenetratetotheedgesofthecrystallitesThefirststepislimitingstepforpolymernanocompositesformationThermodynamicanalysis△F=F(h)-F(h0)=△E-T△S△F＜0indicatelayerseparationisfavorable△F＞0impliestheinitialunintercalatedstateisfavorable△S≈△Schain+△SpolymersaisafsapfappfspAAAAE)(InfluencefactorsofpolymerintercalationOriginalpropertiesofsilicatePolymerarchitectureinteractionbetweensurfaceandpolymera.Organicallymodifiedlayeredsilicatessurfaceb.AddingafractionoffunctionalizedpolymersProcessconditionWAXDpatternsoforganicallymodifiedclay:(a)smectiteclaymodifiedwithC8,C12,andC16phosphoniumsalt;(b)smectite,MMT,andmicaclaymodifiedwithC1