扫描电镜和透射电镜在聚合物研究中的应用PPT课件

-,1,在聚合物纳米复合材料研究中的应用,在聚合物/clay纳米复合材料研究中的应用,在聚合物/Carbonnanotubes纳米复合材料研究中的应用,-,2,1991年，日本电子公司（NEC）的饭岛澄男博士在用电子显微镜观察石墨电极直流放电的产物时，发现一种新的碳结构碳纳米管（CarbonNanotubes,CNTs），自此开辟了碳科学发展的新篇章，也把人们带入了纳米科技的新时代。,History,-,3,什么是碳纳米管？,碳纳米管是一种具有特殊结构（径向尺寸为纳米量级，轴向尺寸为微米量级、两端基本上都封口）的一维量子材料。它主要由呈六边形排列的碳原子构成数层到数十层的同轴圆管。层与层之间保持固定的距离，约为0.34nm，直径一般为22Onm。,-,4,Single-wallnanotubes(left)andMulti-wallnanotubes(right)(fromThomasSwanCompany),(Iijima1991),(Iijima,(B)highmagnification;(C)chitosan/2.0%MWNTsnanocomposite.,-,24,TEMimageofathinsectionofthechitosan/0.8%MWNTsnanocomposite.,-,25,Opticalmicroscopyimagesofchitosan/MWNTsnanocompositefilmscontaining0.8and2.0wt%MWNTs.,-,26,Typicalstress-straincurvesofneatchitosananditsMWNTsnanocompositeatacrossheadspeedof5mm/min.(B)Tensilemodulus(E)andyieldstrengthofchitosan/MWNTsnanocompositesasafunctionofMWNTsconcentration.,-,27,MechanicalPropertiesofNeatChitosanandItsMWNTsNanocomposites,-,28,Conclusions,Thispaperfirstreportsthehigh-performancebiopolymerchitosan/MWNTsnanocompositespr-eparedbyasimplesolution-evaporationmethod.ThehomogeneousdispersionofMWNTsinthematrixdramaticallyimprovedthemechanicalpropertiesofthechitosan.Whencomparedtothoseofneatchitosan,withincorporationofonly0.8wt%MWNTs,thetensilemodulusandstrengthofthenanocompositesaregreatlyimprovedbyabout93%and99%,respectively.,-,29,Meltcompoundingusingtwin-screwmixer,SEMshowinghomogeneousdispersionofMWNTs(1wt%)throughoutPA6matrix,ZhangW.D.,ShenL.,PhangI.Y.,LiuT.X.Macromolecules2004,37,256-259.,onetypicalexample,Nylon6(PA6),研究实例,-,30,A,B,1wt%MWNTs,DispersionMorphologybyTEM,-,31,TensileProperty,-,32,InteractionoffunctionalizedCNTswithpolymerchains,-,33,多壁碳纳米管/聚乳酸纳米复合材料的形态、结晶行为和性能的研究,专业：材料学答辩人:赵媛媛导师：邱兆斌教授,北京化工大学硕士学位论文答辩,2009年4月10日,-,34,论文的研究目的及意义,选取PLLA为基体，以MWNTs作为增强材料，通过溶液超声法制备综合性能更为优越的PLLA/MWNTs纳米复合材料，对其进行改性研究；MWNTs化学修饰与否及百分含量将对其在PLLA基体中的分散性、形态以及PLLA的结晶行为、力学性能和水解行为产生影响；探索聚合物结构与性能之间的关系，达到改善性能和拓展应用领域的目的。尤其是我国将对PLLA进行规模化生产，对其的综合性能进行改善以促进其应用是非常具有现实意义的。,34,-,35,纳米复合材料样品制备,PLLA：由Biomer公司（德国）提供，Mw=2.06105f-MWNTs和p-MWNTs：均购于四川成都有机研究所，直径3050nm.长度10-20m三氯甲烷（氯仿）：北京化工厂，分析纯,PLLA/p-MWNTs和PLLA/f-MWNTsnanocomposites,35,常温超声1h,常温搅拌溶解,MWNTs-CHCl3悬浮液,PLLA溶液,超声搅拌6h,常温挥发,70真空干燥2天,共混液,复合材料膜,MWNTs+CHCl3,PLLA+CHCl3,-,36,表征,扫描电镜（SEM）和透射电镜（TEM）差示扫描量热仪（DSC）偏光显微镜（POM）广角X射线衍射（WAXD）水解实验（HYDROLYTICTESTING）,36,-,37,Figure1.SEMimagesshowinganoverallmorphologyofsurfacesforthenanocomposites:(a)PLLA/p-MWNTsand(b)PLLA/f-MWNTs.,Figure2.TEMimagesshowingnanotubesdispersionfromtheultrathinsectionofPLLAnanocomposites:(a)PLLA/p-MWNTsand(b)PLLA/f-MWNTs.,EffectoffunctionalizationofMWNTs,-,38,Nonisothermalmeltcrystallizationbehaviorandsubsequentmeltingbehavior,Figure3.NonisothermalmeltcrystallizationandsubsequentmeltingtracesofneatPLLAanditsnanocomposites:(a)firstcoolingand(b)secondheating.Table.1.DSCresultsforthePLLAanditsnanocomposites.,aMeltcrystallizationatacoolingrateof5oC/min(firstcooling).bColdcrystallizationataheatingrateof20oC/min(secondheating).cDegreeofcrystallinity,Wc(%)=100(Hm-Hch)/Hm0,Table.1DSCresultsforthePLLAanditsnanocomposites.,-,39,1.2.2.2等温结晶以20/min的升温速率从室温升高到190，恒温3min，消除热历史后，以40/min的降温速率降到一定温度(117.5、120、122.5、125、127.5)，再以20/min的升温速率升高到200。,Figure4.Effectofp-MWNTsandf-MWNTsonthecrystallizationofPLLAat125C:(a)developmentofrelativecrystallinitywithcrystallizationtimeand(b)theAvramiplots.,Table2.CrystallizationkineticparametersforneatPLLAanditsnanocomposites,2.Isothermalmeltcrystallization,-,40,Figure5.Temperaturedependencesof(a)t0.5and(b)1/t0.5forneatPLLAanditsnanocomposites.,-,41,3.POM,Figure6.Spheruliticmorphologiesof(a)neatPLLA,(b)PLLA/p-MWNTs,and(c)PLLA/f-MWNTscrystallizedat140CbyPOM.,-,42,Figure7.WAXDpatternsofneatPLLAanditsnanocomposites.Table3.WAXDdataforneatPLLAanditsnanocomposites.,4.XRD,-,43,Figure8.VariationofweightlosswithhydrolyticdegradationtimeforneatPLLAanditsnanocomposites.,Table.4.ThedatasummarizedfrommasslossrateofneatPLLAanditsnanocomposites.,Hydrolyticdegradationtest,-,44,Effectofthef-MWNTsloadingonthedispersionandmorphology,Figure9.SEMimagesoffracturesurfacesfor(a)PLLA/f-MWNTs0.5and(b)PLLA/f-MWNTs2.0nanocomposites.,-,45,Nonisothermalmeltcrystallizationandsubsequentmeltingbehavior,Figure10.NonisothermalmeltcrystallizationandsubsequentmeltingtracesofneatPLLAanditsnanocomposites;(a)firstcoolingand(b)secondheating.,-,46,Figure11.Effectoff-MWNTscontentsontheisothermalmeltcrystallizationofPLLAat120C;(a)developmentofrelativecrystallinitywithcrystallizationtimeand(b)theAvramiplots.,CrystallizationkineticparametersforneatPLLAanditsnanocomposites.,Isothermalmeltcrystallizationmeltingbehavior,-,47,Figure12.Spheruliticmorphologiesof(a)neatPLLA,(b)PLLA/f-MWNTs0.5and(c)PLLA/f-MWNTs2.0nanocompositescrystallizedat130C.,-,48,DMA,Figure14.(a)Temperature