Study On The Modified Carbon Nanotubes With Small Organic Molecule And Composite Coating

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.