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new material

Resistant and flexible

Carbon nanotubes incorporated into cement and polymers result in more versatile products


Researchers from the Federal University of Minas Gerais (UFMG) have developed a more durable nanostructure, which contains 0.5% of carbon nanotubes, a cylindrical structure formed by carbon atoms whose diameter is a billionth of a meter. This small amount is enough to improve considerably the mechanical properties of the material, such as its resistance. The process whereby these nanotubes are incorporated into the cement was developed by Professor Luiz Orlando Ladeira, from the Laboratory of Nanomaterials at the UFMG Department of Physics and resulted in an international patent that has already been granted. “It’s a totally original incorporation process that improves the mechanical properties of the material and doesn’t make the end product more expensive,” says Professor Marcos Pimenta, from the same department and the coordinator of the National Institute of Science and Technology (INCT) of Carbon Nanomaterials and of a research group that focuses on developing and producing these materials (see more on this subject in issue 118 of Pesquisa FAPESP). The research is being conducted in conjunction with Cauê Cimentos, a Camargo Corrêa Group company.

Another innovative material obtained by researchers from the Department of Chemistry at UFMG, under the coordination of Professor Glaura Goulart Silva, is a flexible polymer for the manufacture of the pipes used in the oil extraction process. In this case, a polymer traditionally employed in this type of pipe, polyurethane, had 1% of carbon nanotubes added to it. “The addition makes the material stronger, which allows the bending of the pipe to be controlled,” Pimenta relates. Also in this line of innovative materials, the group added carbon nanotubes to epoxy, compounds used as adhesives to improve the tenacity and increase the transition temperature of this material. “The addition of nanotubes enables work at higher temperatures.” The idea is to use the composite material as a glue for coating the pipes that carry the oil in case the original material becomes worn or breaks. The two projects are being conducted jointly with Petrobras.

In the UFMG laboratories, the researchers are managing to produce just a few grams of nanotubes a day. However, this is about to change. “We want to produce a few kilograms a day, which would result in around a ton a year,” says Pimenta. To achieve this new level, they plan to set up a pilot plant for producing nanotubes on a pre-industrial scale in the technology complex in Belo Horizonte (BH-Tec), which belongs to the city administration of the Minas Gerais state capital and to UFMG. “We’re at an advanced stage of the negotiations to build a Nanotube Technology Center (CTNanotubos),”  he says. “Our desire is to start building early in 2011.”  The Department of Science and Technology in Minas Gerais has already made R$ 500,000 available for the initial stage of the undertaking, which includes drawing up a business plan. One of the objectives of this plan, which is being prepared by a specialized company, is to determine the legal structure of CTNanotubos, which will be a not-for-profit organization. Overall, some R$ 30 million will be necessary to build a 3, 000 sq. m modular building, with a nanotube production plant and material development laboratories, plus the purchase of equipment and the hiring of some 20 people, including researchers, directors and technologists.

CENTRO DE MICROSCOPIA UFMGElectronic microscope image of a carbon nanotube and cementCENTRO DE MICROSCOPIA UFMG

Productive partnerships
To make CTNanotubos feasible, the researchers plan to enter into partnerships. The idea is that the center produces devices both for academic researchers and for companies. “Along with the production, we are also focusing on the development of new materials, such as cement and polymers with carbon nanotubes,”  says Pimenta. For these two applications, the materials are strengthened using a device with multiple walls, in which various carbon sheets are rolled up in the shape of a tube. For others, a nanotube with a single wall is needed, such as in applications being carried out in partnership with the UFMG Institute of Biological Sciences, in which the devices are used for gene transfection, a method in which RNA is inserted directly into a cell with no intermediary microorganisms.

The nanotube functions like a very thin needle. One of the projects is being conducted in partnership with Embrapa, (the Brazilian Company of Agricultural and Livestock Research) from Juiz de Fora, for selecting cattle embryos.

A group coordinated by the researchers Clascídia Furtado and Adelina Santos from INCT Carbon Nanomaterials is also working on the development of a compound material of epoxy and nanotubes for use in different parts of aircraft, in collaboration with the Brazilian Aerospace Agency. Another project, in partnership with Magnesita, from Minas Gerais, aims at improving the performance of refractory materials used in blast furnaces. The research is in keeping with the worldwide trend of incorporating nanotubes into various types of products in the fields of energy, electronics, medicine and the chemical and petrochemical industries.

All studies currently under way at the UFMG laboratory will be continued in the Nanotubes Center, as well as others that involve safety issues in the production process, during use and after being discarded. “As there are several types of nanotubes, with a single wall, multiple walls, short, long, added to other devices or dispersed in water, one must be aware of the risks involved and care required for each of these forms,”  says Pimenta. To provide scientific answers to the safety issues, the Minas Gerais research group is developing a safety protocol suitable both for people and for the environment.