【作者】 陈传盛；

【导师】 陈小华；

【作者基本信息】 湖南大学 ， 材料物理与化学， 2006， 博士

【摘要】 碳纳米管独特的结构和优异的性能,已引起人们利用它们制备纳米复合材料的极大兴趣。然而,要发挥碳纳米管改性复合材料的先进性,关键在于碳纳米管能否以纳米级水平分散于基体中并与基体形成牢固结合。为了达到这一目的,必须在界面结构及性质设计的基础上,对碳纳米管进行有效的修饰。这方面的研究是近几年发展起来的新兴领域,尚处于起步阶段。在修饰物质、修饰方法、界面结构、特性及应用等方面还需要深入的实验和理论研究。本论文从碳纳米管的制备、纯化、亲水和亲油基团在碳纳米管表面的嫁接、氧化物对碳纳米管的包覆,到修饰后在水或油溶液中的分散性能、界面结构及特性、分子水平的复合技术、微观结构及相关性能的测试和分析,特别是有关摩擦学的性能等,展开了较深入的研究,并讨论和分析了相关的修饰机理。研究具有基础性和前瞻性,兼具重要的理论意义和广泛的应用前景。首先,研究了催化裂解法高产率地制备碳纳米管的工艺及其液相氧化法纯化工艺。扫描电镜、透射电镜、XRD和拉曼光谱结果表明,硫酸和硝酸混合酸处理能够获得纯净的碳纳米管,而没有破坏碳纳米管的结构。此外,红外光谱表明纯化后的碳纳米管表面拥有丰富的羟基和羧基官能团,这为下一步进行碳纳米管的修饰打下了基础。其次,研究了有机小分子阳离子表面活性剂十六烷基三甲基溴化胺和阴离子表面活性剂柠檬酸修饰碳纳米管,并对其在水中的分散性能进行了研究。实验结果表明,通过有机小分子表面活性剂的修饰提高了碳纳米管在水中的分散性能。另外,还通过Zeta电位仪和粘度仪的测量探讨了碳纳米管在水中的分散机理。第三,利用有机小分子硬脂酸修饰碳纳米管,研究了碳纳米管在润滑油中的分散性能及其作为润滑油添加剂的摩擦学性能。实验结果显示,硬脂酸修饰不仅改善了碳纳米管在基础油中的分散性能,而且提高了基础油的减摩抗磨能力。当硬脂酸与碳纳米管的质量比为2:1、修饰碳纳米管浓度为0.45%时,碳纳米管作为润滑油添加剂的减摩抗磨性能最佳,能够使基础油的摩擦系数下降10%,磨损量降低30%-60%。此外,还研究了油酸、正辛醇、正十二醇、正十六醇修饰碳纳米管。初步结果表明,油酸修饰能够提高碳纳米管在基础油中的分散能力,而且比硬脂酸修饰更能提高基础油的减摩抗磨能力。第四,运用氨水和柠檬酸两步修饰碳纳米管,成功地把氨基官能团和柠檬酸分子引入碳纳米管的表面,提高了碳纳米管的活性和分散性能。在此基础上,采用溶胶凝胶法进行氧化锌和氧化锡包覆多壁碳纳米管。透射电镜、扫描电镜和红更多还原

【Abstract】 Carbon nanotubes (CNTs) have attracted great interest to be made use of for the preparing composite material because of the inimitable structure and the outstanding properties. However, the key to develop the CNTs modified composite material’s superiority is whether the CNTs can be dispersed into the matrix in nano-scale and combine with the matrix fast and hard. For this purpose, the CNTs have to be modified effectively based on the interface structure and property design. This research aspect is a new field developed recently, and it is in primary stage. The further experimental and theoretical studies are needed in modification material, modification methods, interface structure, property and application etc. In this dissertation, the research work of CNTs ranging from the preparation, purification, grafting the hydrophile and lipophilic groups onto the surface of CNTs, the coated CNTs with oxide, to the ability of dispersion in water or oil after the modification, interface structure and property, composite technology of molecule level, microstructure, testing and analysis of correlative properties, especially the properties about tribology has been carried out. Moreover, the correlative modified mechanism are discussed and analysed. This research is fundamental and pioneering, and is of great significance on theory and extensive application.Firstly, the technics of high yield preparation of CNTs was studied by the method of catalytic chemical vapor decomposition. Moreover, the technics of purified CNTs was investigated. The experimental results of scanning electron microscope (SEM), transmission electron microscope (TEM), Raman spectroscopy and XRD, show that after the as-prepared CNTs are purified with the mixture of sulfuric acid and nitric acid, not only the CNTs are purified, but also the structure of CNTs is not destroyed. Furthermore, the results of Infrared spectroscopy illuminate that the hydroxyl groups, carboxylic groups are introduced onto the surface of CNTs.Secondly, the CNTs were modified by the cetyl trimethyl ammonium bromide (CTAB) and citric acid (CA), respectively, and the dispersion properties in aqueous solution were studied. The experimental results illuminate that the dispersion of CNTs in aqueous solution is improved by modification. Furthermore, the dispersed mechanism of MWNTs in de-ionized water was discussed through the study of Zeta potential analyzer and viscosity meter.更多还原