Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Rice refining production of pure nanotube fibers

03.09.2004


Pioneering fiber production methods similar to those of Kevlar(R), Zylon(R)

Rice University scientists are refining pioneering chemical production methods used to make pure carbon nanotube fibers. Research appearing in tomorrow’s issue of the journal Science describes the scalable production techniques, which yield highly aligned, continuous macroscopic fibers composed solely of single-walled carbon nanotubes (SWNTs), the type of carbon nanotubes with the best mechanical and transport properties.

Rice chemist Richard Smalley, director of Rice’s Carbon Nanotechnology Laboratory, said the production methods CNL is pioneering for single-walled carbon nanotube fibers are similar to those used in making two of the world’s strongest commercially available fibers, Kevlar® and Zylon®. CNL’s fiber research team expects the development path of pure nanotube fibers to follow a similar track to those two as well, with several years of refinement in processing and a significant investment needed for research prior to commercial availability.



The Air Force and its industrial partners spent a decade and more than $100 million perfecting Zylon, the strongest fiber on the market today. Zylon is about twice as strong as Kevlar, the material used to make much of the world’s bulletproof body armor. Ultimately, CNL researchers believe pure nanotube fibers hold the promise of being 10 times stronger than Zylon.

"The early results are auspicious," said Smalley, University Professor, the Gene and Norman Hackerman Professor of Chemistry and professor of physics at Rice. "We’ve got no impurities, our densities are about 77 percent of what’s theoretically possible, and we’re confident that the strength and conductance will improve as we refine the heat treatment, spinning and other elements of production."

In 2000, a team of researchers centered at Rice in Smalley’s research group began in earnest to spin a fiber from SWNTs dispersed at high concentration in a strong acid. Ongoing work at that time showed that SWNTs interact strongly with sulfuric acid and assemble into endless spaghetti-like domains composed of a myriad of highly aligned, mobile SWNTs. This Science article is the fifth paper reporting the four-year journey that resulted in the current discovery. Researchers at the University of Pennsylvania’s Department of Materials Science and Engineering helped determine the structure of the nanotube acid dispersion. "The SWNT fiber project is one of the ’holy grails’ of nanotechnology -- spin a pure single-walled nanotube fiber with the highest strength of any fiber possible," said paper co-author Wade Adams, director of Rice’s Center for Nanoscale Science and Technology (CNST).

Adams said Rice’s fiber project was one of the factors that enticed him to join CNST in 2002 following his retirement after 32 years of service at the Air Force Research Laboratory at Wright-Patterson Air Force Base in Dayton, Ohio. "The Air Force developed what is now called Zylon fiber from a rod-like polymer, with tensile properties twice that of Kevlar fiber," said Adams. "SWNTs are predicted to have tensile strengths many times that of Zylon or Kevlar, based upon the much greater theoretical strength of the single molecule carbon nanotube. However, unlike Zylon and Kevlar, SWNTs are also excellent conductors of electricity and heat. This unique multifunctionality makes them candidates for many critical applications beyond structural ones."

Nanotubes are hollow cylinders of pure carbon that are just one atom thick. In addition to being very strong, nanotubes can also be either metals or semiconductors, which means they could be used to manufacture materials that are both "smart" and ultrastrong. NASA, for example, is researching how composite materials containing nanotubes could be used to build lighter, stronger aircraft and spacecraft.

Chemically, carbon nanotubes are difficult to work with. They are strongly attracted to one another and tend to stick together in hairball-like clumps. Scientists have developed ways to untangle and sort small amounts of nanotubes but have not found a satisfactory way to achieve stable dispersions suitable for processing. To date, the medium of choice has been detergent and water solutions that contain less than 1 percent of dispersed nanotubes by volume and are processed with polymer solutions. Such concentrations are too low to support industrial processes aimed at making large nanotube fibers. Moreover, it is difficult to remove all the soap and polymer and convert the nanotubes back into their pure form.

Rice’s team believes they have overcome the major hurdle to industrial production of macroscale SWNT objects -- finding a way to store large amounts of nanotubes in liquid form. By using strong sulfuric acid, a team of chemists and chemical engineers was able to disperse up to 10 percent by weight of pure carbon nanotubes -- more than 10 times the highest concentrations previously achieved. This new processing route uses no polymeric additives or detergents, which were used in previous processing methods and are known to be an obstacle to commercial scalability and final product purity.

Jade Boyd | EurekAlert!
Further information:
http://www.rice.edu

More articles from Materials Sciences:

nachricht Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously
17.01.2017 | Sonderforschungsbereich 668

nachricht Manchester scientists tie the tightest knot ever achieved
13.01.2017 | University of Manchester

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Water - as the underlying driver of the Earth’s carbon cycle

17.01.2017 | Earth Sciences

Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

17.01.2017 | Materials Sciences

Smart homes will “LISTEN” to your voice

17.01.2017 | Architecture and Construction

VideoLinks
B2B-VideoLinks
More VideoLinks >>>