Carbon nanotubes manufactured materials

From the data obtained so far one could conclude that work with nanotubes should be done with precaution, and certain safety actions need to be considered working with nanotubes in laboratories and during their manufacture. The success of nanotechnologies will depend on continuing research in the area of toxicology of carbon nanotubes and the materials based on them. 

Semiconductor A generic term for a device that controls electrical signals. It specifically refers to a material (such as silicon, germanium or gallium arsenide) that can be altered either to conduct electrical current or to block its passage. Carbon nanotubes may eventually be used as semiconductors. Semiconductors are partly responsible for the miniaturization of modem electronic devices, as they are vital components in computer memory and processor chips. The manufacture of semiconductors is carried out by small firms, and by industry giants such as Intel and Advanced Micro Devices. 

Carbon nanotubes (CNTs) have shown exceptional stiffness, strength and remarkable thermal and electrical properties, which make them ideal candidates for the development of multifunctional material systems [22], Nowadays, CNTs are dispersed within polymer in order to improve their mechanical and electrical properties [23], Therefore, reinforcement of PB films by CNTs might be a strategy for manufacturing mechanically robust ion-... 

Globally, carbon nanotubes have a positive effect on the mechanical properties of all the composites with PVA matrices described in the previous sections. However, the enhancement of mechanical properties differs substantially from a material to another, depending on the type of nanotubes, or on the process used to manufacture the composite. The Young s modulus and the strength are deduced from usual tensile experiments. As depicted in Figure 11.4, PVA/nanotube composites generally follow the same tensile behavior, with a short elastic regime on the first percent strain, followed by a more or less extended plastic behavior. 

Since Iijima reported carbon nanotube (Figure 9.16) preparation and its microstructure in 1991, [98] carbon nanotubes have attracted enormous attention. Because of their unique structures, these materials exhibit a variety of interesting physico-chemical properties, and they may play an important role in manufacture of nanodevices. 

Most processes in the fine chemical industry are typically carried out in batch mode, where the powdered catalyst is suspended in the reaction medium. For the production of bulk chemicals extruded or granulated carbon-supported catalysts are used in fixed-bed reactors. To date, the most important carbon supports from an industrial point of view is activated carbon and carbon black. The main reason for the success of those materials is their commercial availability and variety of different grades, so that the final calalyst can be lailored to the end user s requirements. On a worldwide basis, 908,000 metric tons of activated carbon was produced in 2005 [5], Only a small fraction of that is used as catalyst support. Other carbon supports, such as carbon aerogels and carbon nanotubes, are in the focus of modem catalytic research but so far have not been used in commercial processes. Since there are various scientific pubhcations in the field of carbon and its use as catalyst support, the focus of this contribution is on the industrial importance of carbon supports for precious metal powder catalysts, their requirements, properties, manufacturing, and industrial applications. 

The characteristics of ECPs can be significantly increased by the formation of composites between ECPs and other materials, for example, carbon (including carbon nanotubes), inorganic oxides and hydroxides, and other metal compounds. Examples of some such composites and their electrochemical characteristics are given in Table 28.4. Such electrodes can be used to manufacture symmetrical devices (type I or type in) of the same positive and negative electrodes. Composite materials... 

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