Market Hype

Production and Synthesis

The Chemical Vapor Deposition (CVD) technique is the most commonly used for making nanotubes. Companies such as CNRI, Nanocyl, NanoLab, Nanoamor, and Shenzhen Nanotech use CVD; MER, Nanocarblab, NanoLedge use arc discharge; ILJIN uses both CVD and arc discharge. The production methods have not yet been mastered and thus nanotubes have yet to be produced in mass quantities. Some SWNT producers may be moving away from the older methods and using fluidized beds and other high throughput methods, in order to scale production with relatively low costs.

Raymor Industries utilises a hybrid of existing CVD and Arc processes which uses specially designed plasma torch (design cannot be revealed for competitive reasons) to explode molecules in highly efficient way. It is a clean process; there is no emission of toxic gas. Hydrogen molecules can be recycled for environmental purposes. The process creates a large quantity of nanotubes compared to the original mass. The single-walled nanotubes formed are of a high quality and high purity.

Depending on the method of synthesis, impurities in the form of catalyst particles, amorphous carbon, and non-tubular fullerenes are also produced. Thus, subsequent purification steps are required to separate the tubes from other forms of non-tubular carbon. Purification involves chemical processes like acid reflux, filtration, centrifugation, and repeated washes with solvents and water. Typical nanotube diameters range from 0.4 to 3 nm for SWNTs, and from 1.4 to more than 100 nm for MWNTs. It has been established that a nanotube's properties can be tuned by changing its diameter.

The main driving force for investment in carbon nanotubes R&D is their promise to offer improvements in materials capabilities across a wide range of applications. This is of huge strategic importance to sectors which historically leverage technological advancements. Carbon nanotubes enable radical design changes for a wide variety of markets by permitting combinations of properties not previously possible in materials design and affording multi-functionality for increased efficiency. The challenge is translating the excellent combination of nanotubes properties on the nanoscale to structural properties on the macroscale. Current hindrances include: inconsistent quality of carbon nanotubes supply; dispersion; characterization of carbon nanotubes nanocomposites; and scaling down processing equipment to work around the low CNT supply.

The majority of current global revenues for carbon nanotubes are generated by relatively large-scale manufacturing of bulk materials for applications where electrical conductivity, increased mechanical performance and flame retardancy are primary design drivers. Composites, field emission devices and batteries are the most prominent and commercially viable current applications. Next generation products will incorporate sensing capabilities and multi-functionality and lead to greatly increased revenues over the next 3-10 years. Prices will also fall over the next few years as large companies begin to produce commercial-scale volumes of nanotubes. Large multi-nationals such as Arkema, Bayer and Showa Denko have significantly ramped up production levels; companies in China and Russia are also producing significantly cheaper nanotubes.

Main markets at present for nanotubes are aerospace, automotive, defence and electronics & data storage; generally as multi-purpose compound enhancers. In aerospace, nanotubes already find application as additives for ESD and EMI shielding; as electrostatic coatings and component reinforcement additives in the automotive sector; in various defence applications; and as conductive polymers and composites for field emission displays. This represents the first generation of nanotubes products; the next generation will be based on controlled fabrications leading to multi-functional and sensory capabilities.

The electronics and data storage market is likely to see the biggest penetration to 2015, with the performance enhancing properties of carbon nanotubes allowing electronics manufacturers to meet demanding market needs across a variety of applications. Their incorporation into the displays applications will also increase demand, with a conservative revenue forecast of $1.07 billion by 2015.

There is a great demand in the market for carbon nanotubes, especially in the electronics and polymers sectors; production and price are restraints at present but this is changing. A kilogram of carbon nanotubes used to cost up to $1,000, but now, as a result of targeted research and development activities, companies has managed to significantly lower the price-per-kilogram, thereby enabling the development of new, industrial applications. For example, the automotive industry will soon be able to reduce the cost of painting plastic fenders: adding just minimal amounts makes the semi-finished parts electrically conductive, and this new material property supports more efficient and environmentally friendly coating processes based on counter charged, solvent-free powder coating particles.

In most cases, CNTs are used as an additive to add value to existing products or to develop new products such as Field Emission Displays displays. The advantage as an additive is usually an enhancement of the properties with a low loading of nanotubes. This low loading also offers new possibilities like transparency in coatings. Other advantages can be lower manufacturing cost using a CNT-based technology.

One of the biggest challenges facing the carbon nanotube producers is the ability to obtain significant quantities of the desired type of carbon nanotube. High throughput experimentation is one possible approach that holds promise for searching the best catalyst for growing the desired nanotube. Other issues that assume significant importance is identifying the most likely nanomaterial and then setting up a large infrastructure for a scalable mass-manufacturing process. Some techniques that are used to build electronic components with carbon nanotubes are inappropriate for mass production.

Expensive, small scale production of nanotubes as well as clumping, lack of binding to the bulk material, and temperature effects are therefore key barriers to their application in the industry. Although there are challenges ahead, carbon nanotubes have opened up a host of practical applications in the nanometre scale.

Дата добавления: 2014-10-31