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Nitrogen doped single-walled carbon nanotubes has been prepared using the arc discharge method. The material contains in average more impurities like pristine (pure) carbon nanotube material produced with the same method. We have tested several purification methods like the oxidation in hot air. First tests have shown that nitrogen-doped nanotubes exhibit a higher reactivity and are therefore less inert towards oxidative purification methods used for carbon nanotubes. We want to present a new purification method. It is based on the oxidation of the carbon impurities, homogeneously dispersed in boiling tertrachloroethan under airflow. The purity of the sample was investigated using scanning electron microscopy and transmission electron microscopy. Another part will present the characterization of chemically modified nitrogen-doped nanotubes after purification and first steps of the functionalisation of the hetero-nanotube material. Because of already existing model systems with hetero fullerenes, we have chosen a ‘Mannich’-like reaction for the modification of nitrogen-doped nanotubes. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR] more...

The main issue in the research field of NT composites is the load transfer and homogeneity of the composites. Our investigations open a route to reach this homogeneity by functionalizing these nanotubes. We have tested several functionalisation methods and here, we want to focus on the addition of amines to the oxidized nanotube sidewalls. Using bi-functionalities, a chemical link between the nanotubes and polymer should result in more stable and homogeneously dispersed composites. The chemistry behind the modification of the nanotubes and the process in lab scale will be discussed in detail. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR] more...

The question of possible technological applications quickly aroused after the discovery of the unique physical properties of single-walled carbon nanotubes (SWCNTs). In this context, a wide range of initial approaches towards organic nanotube chemistry have been developed within the last few years. This also includes the covalent functionalization of the SWCNT sidewalls with nitrenes, carbenes or radicals, to increase solubility in organic solvents. With the use of bis-alkoxycarbony-lazides to create in-situ di-nitrenes, it should be possible to link individual SWCNTs and small bundles. The purpose of these experiments is to give the possibility for increasing the understanding of the chemical behaviour of SWCNTs and to provide further proofs for the occourance of this type of reaction. This can also be seen as a new way for forming nanotube materials for exploiting their unique mechanical properties. The results obtained are discussed in this presentation. SEM, XPS, XRD and Raman spectroscopy are used as characterization tools. © 2003 American Institute of Physics [ABSTRACT FROM AUTHOR] more...

A new synthesis method has been invented for the production of carbon nanotubes. We have called this method the aerosol method since the fundamental synthesis routine is to create aerosols of organic solvent and metal particles by atomising a solution of a metal salt in a solvent using pure hydrogen gas. This method enables us to easily control the size of the catalyst particles. Reactions have been carried out at 700°C and 1000°C and in both cases multi-walled carbon nanotubes have been produced. The tubes are characterised using scanning and transmission electron microscopy, and X-ray diffraction. [ABSTRACT FROM AUTHOR] more...