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Ultra-Strong Nanotube Composites
TheMatt writes "In a story that makes you say "Cool!", Nicholas Kotov and co-workers have
created a nanotube composite material six times stronger than carbon-fiber composites. Their final product is a crosslinked material which appears to be just as strong as silicon carbide and tantalum carbide!"
Here's the closing words of the article... ...so don't expect to see such stuff outside of small-quantity/cost-no-object uses anytime soon.
"But carbon nanotubes are still expensive to produce, and several teams are looking for production methods that would be viable on a commercial scale."
The "as hard as some ultrahard ceramic materials used in engineering." description (also from the article) suggests that it won't be much good for space elevator cable anyway. I'd bet than an elevator cable needs to flex some under loads ranging from tidal forces to microimpacts.
It's easy to make up & spread cool- and credible-sounding stuff. Finding & checking hard facts is hard work.
Not...tantalum carbide...?
- undoware.ca
They don't give much detail on anything. They seem to be saying the material is both strong and stiff, but you might be able to play with the properties
Flexibility isn't an issue. imagine eachnanotube as a molecule. like steel or carbon, it can probably be patterened in such a way as to make it have enough flexibility.
Sig (appended to the end of comments you post, 120 chars)
nanotubes are of course still too expensive to produce, but still, the idea to make something 6 times stronger than traditional carbon fibers just makes me really want these science-geeks figure out how to make a computer chassis out of it so i can throw it at someone at my next lan party.
.cig - what you do after winning a good flame war
(or at least, "data *I* can't understand) can be found by following the "references" link at the bottome of the linked page.
It lead me to a nature.com, where, after registering with them (and opting out of EVERYTHING, which was easy), I read the Far More Technical nature article. It went way over my head.
WAY over:
"
The mechanical properties of the layered composites were tested on a custom-made thin-film tensile strength tester (McAllister) recording the displacement and applied force by using pieces cut from ((PEI/PAA)(PEI/SWNT)5)6 and ((PEI/PAA)(PEI/SWNT)5)8 freestanding films. The tester was calibrated on similar pieces made from cellulose acetate membranes and nylon threads. ((PEI/PAA)(PEI/SWNT)5)6 and ((PEI/PAA)(PEI/SWNT)5)8 samples had an average thickness, measured by TEM, of 0.75 and 1.0 m respectively.Their typical stress ( ä) versus strain ( å) curves differed quite markedly from stretching curves seen previously for SWNT composites10 and for LBL films made solely from polyelectrolytes, (PEI/PAA)40, obtained by the same assembly procedure (Fig. 4b). They displayed a characteristic wave-like pattern,a gradual increase of the d ä/d åderivative, and the complete absence of the plateau region for high strains corresponding to plastic deformations (Fig. 4a).The latter correlates well with the enhanced connectivity of SWNT with the polymer matrix (Fig. 2).
"
And that's the relatively clear stuff. I could actually follow some of it. Yow!
Fooz Meister
...they are far stronger and stiffer than those used to make carbon-fibre tennis-rackets...
...maybe that simile could use a little work?
Yeeaaaa... Usually tennis rackets are designed to bend. They do make rackets that are intended to be stiff, but even those are supposed to bend a little...
Also, pro players brake their rackets a lot... so do amatures... I broke about 3 "carbon-fibre" rackets just by dropping them.
Anybody have any more information or links that explain how flexible this new material is?
Yup. If the nanotubes are chemically bonded to the matrix, as the article suggests, and it is comprised of 50% nanotubes, it would be extremely stiff. Far stiffer than any carbon fiber composite.
As far as flexibility of a physical shape (thread, cable) goes, anything is flexible if it is thin enough that opposite faces don't develop significant compressive/tensile stresses on bending. This is one reason why most cables are a bundle of smaller wires/threads. (Reliability is another issue, since if one goes it doesn't take the others out with it, as would happen if a cable was a solid piece of material (e.g., metal)). You can bend a multifilament line easily, whereas a solid cable of the same diameter would either be too stiff to bend easily, or would break or permanently deform as a result of the bending.
So, tethers or cables made from these nanocomposites would most likely be multifilament, making them flexible enough to be spooled easily, while still being very strong.