Frequently Asked Questions (FAQs)
- What are carbon nanotubes?
- Are carbon nanotubes really new?
- How are Baytubes® produced?
- What is so special about Baytubes®?
- What are the potential benefits of Baytubes®?
- Where are Baytubes® already used?
- What is Bayer’s contribution to safety research?
- How is Bayer supporting the global effort towards safety research in nanotechnology?
- What does Bayer do to ensure the responsible production and use of Baytubes®?
- Are Baytubes® safe for human health and the environment?
Q: What are carbon nanotubes?
A: Carbon nanotubes are regarded as one of the prime examples of nanotechnology. Scientists are really excited by their properties and potential applications. Carbon nanotubes (CNTs) consist of rolled up sheets of graphite. Depending of the number of sheets and their structure, size and properties may vary.
Structures consisting of one sheet of graphite (called graphene) are single wall carbon nanotubes (SWCNT), those consisting of two sheets double wall carbon nanotubes (DWCNT) and those consisting of multiple sheets are generally known as multi wall carbon nanotubes (MWCNT).
These different structures show different properties (conductivity / semi conductivity / thermal conductivity, mechanical strength) and morphology (length, diameters, shape, …). Typically they measure a few nanometers in diameter and several microns in length. Parameters such as processability and handling, exposure potential as well as toxicological and ecotoxicological profile may also differ widely.
topQ: Are carbon nanotubes really new?
A: Above all, CNTs have been present in the world for a long time. Indeed, they can be produced from natural processes such as global combustion resulting from forest fires.
(Ref. Water Research 38 (2004) 4282-4296, Murr et al.)
They can also be formed from non-natural processes such as propane and natural gas flame emissions from domestic stoves.
(Ref. Nanosci. Nanotechnol. 2004 Sep; 4(7):716-18, Bang et al.)
Moreover CNTs have been used for a long time without suspecting the “nano” nature of the products. In India traditional cosmetics for example, it was recently discovered that CNTs are one of the main component of the eyeliner “kajal”.
(Ref. http://in.news.yahoo.com/051210/48/61hau.html)
New stories of the legendary Damascus swords revealed the presence of carbon nanotubes. According to legend, the blades can cut a piece of silk in half as it falls to the ground and maintain their edge after cleaving through stone, metal, or even other swords. CNTs might explain these unique features.
(Ref. http://news.nationalgeographic.com/news/2006/11/061116-nanotech-swords.html)
Q: How are Baytubes® produced?
A: Carbon nanotubes were officially discovered about 15 years ago and have since then turned out to be a highly versatile material thanks to its remarkable properties. Until the end of 2005, however, the price of up to EUR 1,000.00 per kilogram and the fluctuating production quality prevented a more widespread use of nanotubes. What is new is Bayer’s innovative development of a new method for synthesizing carbon nanotubes, which paves the way for these high potential nanomaterials to be used in large scale industrial applications. In addition to cost-effective production, it ensures constant material purities of more than 95 percent. This constitutes a small revolution in the field of nanotechnology. Bayer MaterialScience is marketing the nano sized materials under the trade name Baytubes®. Bayer MaterialScience recently set up a second pilot production plant with an annual capacity of another 30 tons expanding the capacity to 60 tons in 2007, which will make Bayer MaterialScience one of the top 3 carbon nanotubes producers worldwide.
topQ: What is so special about Baytubes®?
A: Baytubes® differ from other natural or engineered nanotubes in many ways. They are of high purity (>95% standard grade, >99% can be achieved in high purity variations) and show no other residue than from the catalyst. and catalyst carrier. In particular, TEM analysis indicates the absence of carbon soot in the product. They show a high bulk density consistent with the large agglomerate structure seen already with the naked eye whilewith electron microscopy. the entangled nature of the Baytubes® can only be observed with electron microscopy. The size of the agglomerates (>100µm) in Baytubes® facilitates the handling at the workplace by reducing the potential of exposure via inhalation.
topQ: What are the potential benefits of Baytubes®?
A: Baytubes® are typically used as additives to a polymer matrix or in metal systems. The benefits of Baytubes® are based on a set of three properties which confer a unique advantage to the materials in which they are incorporated. These are greatly improved mechanical strength, electrical conductivity and thermal conductivity.
topQ: Where are Baytubes® already used?
A: Baytubes® are extremely resilient. They might only have a quarter of the mass of steel, but they are 5 times stronger when subjected to mechanical loads. They also conduct electric current as effectively as copper. The tiny tubes can be used to produce extremely robust plastics that are constructed in the same way as reinforced concrete. Baytubes® are already used in epoxy systems, thermoplastic systems and coating systems. Final products are typically high-tech sport equipments; injection molded and extruded parts as well as conductive coatings. An excellent example is the current use of Baytubes® in skis, ski poles, hockey and floorball sticks, baseball bats or surfboards. In those cases, Baytubes® help to improve the mechanical strength of some of those articles as well as reducing weight in some others. Baytubes® can be used to make rotor blades for wind turbine plants lighter, longer and thus more efficient. And in the automotive industry, the use of Baytubes® in plastics can avoid the need for expensive production steps. These examples will open the door to more demanding applications in energy and aircraft industry.
topQ: What is Bayer’s contribution to safety research?
A: Nanotechnology is one of the key technologies of the 21st century. Nanomaterials are being used increasingly in many different spheres of our lives, and for this reason their safe use must be ensured by way of detailed, accompanying research into the potential related risks. After all, the economic success of nanomaterials depends to a great extent on the acceptance of nanotechnology in society. In addition to its innovative activities, Bayer for many years now has been researching safety in the field of nanotechnology . We want to help gather and document fundamental knowledge on this subject. In line with our Responsible Care principles, we commit ourselves to ensure the safety of our products.
A key aspect of nanomaterial safety is the improvement not only of measurable methods required to characterize nanomaterials and determine workplace exposure, but also of toxicological test methods (in-vitro and in-vivo). The NanoCare and TRACER projects funded by the BMBF – to which Bayer is making significant contribution – are pursuing these objectives.
topQ: How is Bayer supporting the global effort towards safety research in nanotechnology?
A: Bayer MaterialScience identified related risk areas early on and initiated the necessary safety research. For example, Bayer is founding member of the DECHEMA Responsible Production and Use of Nanomaterials Working Group (December 2003) as well as being a founding member of PACTE (Producers’ Association of Carbon Nanotubes in Europe) since September 2006. Within PACTE Bayer MaterialScience works for example to ensure an efficient exchange of good practices for the production and processing of CNT with other producers of CNTs. Aspects such as safety research, regulatory questions as well as broader societal dialogue are also of primary importance. In close cooperation with other companies in the Chemical Industry Association of Germany (VCI), we are currently developing a Code of Conduct for the safe handling of nanomaterials.
In addition to the active dialogue within associations, Bayer MaterialScience strongly supports a number of government-funded projects devoted to safety research issues. One priority project addresses the safe handling of nanomaterials in manufacturing and processing, as well as the safety of consumer products, in terms of both human health and the environment.
In Germany, examples include three-year NanoCare and TRACER projects supported by the WING (Material Innovations for Industry and Society) group of the Federal Ministry of Education and Research (BMBF). Bayer is participating in both projects (TRACER focuses on CNTs). Within the framework of NanoCare, stakeholders are to be included in a discussion of the projects results.
topQ: What does Bayer do to ensure the responsible production and use of Baytubes®?
A: In manufacturing Baytubes®, we take all technical, organizational and personal protective measures necessary to ensure the safety at the workplace. This applies both to plant equipment (closed and automated systems, extraction systems, waste gas combustion) all the way down to personal protective clothing to employees.
Moreover, together with our technical departments, we have elaborated a Product Stewardship Program specifically for Baytubes®. In this context, we also make a vital contribution to advancing the necessary test methods. Only in this way can toxicological studies be carried out effectively and salient conclusions drawn from them concerning human health and the environment. No toxicological testing performed so far on Baytubes® has shown any adverse effects.
In addition to strict internal safety processes, Bayer MaterialScience maintains close contacts with its customers and supports them to ensure the safe handling of its products. The primary tool for safety communications with our customers is the Safety Data Sheet which is provided to each customer. Any new information relevant for the safety of human health and the environment is used to regularly update the SDS when necessary.
topQ: Are Baytubes® safe for human health and the environment?
A:
Safety for consumers
Baytubes® are not sold to consumers. They are intermediates chemical substances that are typically used as additives in polymer systems where they achieve an improvement in the properties of the end-product. There is no direct contact of nanoparticles with consumers because Baytubes® are embedded in the polymer matrix to form the nanocomposite in the final products.
Safety for the environment
At Bayer MaterialScience we regard it as our responsibility to current and future generations to continually improve our environmental performance (BMS values) Activites towards ensuring safety for the environment with Baytubes® include the minimization of the potential exposure on the one side, and the testing activities to clarify the ecotoxicological profile of the substance on the other side. Concretely, a release of Baytubes® from the production into the air is prevented by using high efficiency filters as well as burners to ensure that the carbon material is entirely degraded to combustion. As the production process is a gas process and does not involve water of solvents, a release into the water is also prevented. Additionally an internal testing program has been implemented to determine the ecotoxicological profile of the substance. No ecotoxicological testing performed so far on Baytubes® has shown any adverse effects.
