Ultra-Strong Nanotube Composites 29
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!"
Flexibility? Tech usefulness? (Score:2, Interesting)
Re:Flexibility? Tech usefulness? (Score:3, Insightful)
Re:Flexibility? Tech usefulness? (Score:2, Informative)
The strength of this material will be suffice for space "tethers" that can work as slings to catapult loads into higher orbits, or even give them escape velocity.
Genuine space elevators require a strength several orders of magnitude greater, but the maximum strength of individual nanotubes makes it theoretically possible to get there.
For details, see an article in American Scientist (NOT Scientific American) 5-7 years ago. It discussed the minimum strength required, and the reasons carbon nanotubes just might work.
Ironically, Buckminster Fuller, the discoverer of Buckminsterfullerene (carbon nanotubes can be seen as tubular extensions of these molecules), was a friend of Arthur C. Clarke, the author of the first space elevator novel "The Fountains of Paradise".
Neither Fuller nor Clarke suspected that Fuller's discovery one day might serve as the foundation to high-strenght materials that could make space elevators possible !
Yours Birger J.
Re:Flexibility? Tech usefulness? (Score:2, Informative)
R. Buckminster Fuller did not discover Buckminsterfullerene.
Buckminsterfullerene was named after him because it resembles a geodesic dome, which R. Buckminster Fuller invented.
Re:Flexibility? Tech usefulness? (Score:2, Informative)
The name Buckminsterfullerene was picked because Richard Buckminster Fuller created the geodesic dome, which is essentially what a half of a buckyball looks like.
Following the buckyball's discovery, people all over began to create other things: different-sized buckyballs, bucky-ears, bucky-heads, and the famous buckytube. The buckytube gradually became renamed "nanotube" and that's where we are today!
JoeRobe
Re:Flexibility? Tech usefulness? (Score:3, Informative)
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.
No big uses soon... (Score:3, Insightful)
"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.
Re:No big uses soon... (Score:4, Insightful)
A space elevator would be very long, and over that length it would have a lot of flexibility. I'd say that this stuff is quite promising.
Re:No big uses soon... (Score:3, Insightful)
The article lacks a lot of "crucial detail" about the material itself. Understandable, since it *is* written for the general public. Hopefully we'll see some hard engineering data for the material listed sooner or later.
As for uses... cost never means much to the military. If testing shows it a suitable replacement for mor expensive, heavier materials (for example, aircraft skin), then we'll see an industry grow to satisfy the military demand for it, and eventualy spill over into the civilian market.
=Smidge=
Re:No big uses soon... (Score:5, Informative)
Materials have the following attributes (and others of course):
Now, stiffness is one of the important ones. High Young's modulus (stiffness) good, low Young's modulus bad. Stiff and light is better; stiff, light and tough really attracts attention.
For a very readable introduction to this, I recommend The New Science of Strong Materials (or why you don't fall through the floor) by J.E. Gordon [nous.org.uk], also his Structures [nous.org.uk].
Re:No big uses soon... (Score:2, Interesting)
Graphite composite structures tend to be limited by static strength (ie they will break before they deform too much) and metallics are limited by fatigue strength.
Glass fibers actually have a very high strength but most of the time you cant use it all because of the felxibility. Graphite was going to replace aluminum in airplanes until we found out its vulnerable to impact damage (though that's changing with newer resins). Kevalar was going to change the world until we found out it has no compression strength (I once had to certify a Kevlar wing on a surveillance drone: Kevlar is like designing with chain...you can pull on it but don't push).
I'm sure eventually the pro's and cons of this new stuff will come out. Personally I'd like to know about it's damage tolerance.
Re:No big uses soon... (Score:1)
That may be true over the entire length of the cable, but, in all scenarios with which I am familiar, the cable must be wound on a coil small enough to fit in the cargo hold of the Space Shuttle or other spacecraft.
Now, if there were an alternate method of deployment that did not require such a tight radius (such as orbital manufacture), this problem would not occur.
It may also be possible to manufacture a more flexible cable by using a different polymer, different proportions, etc.
Re:No big uses soon... (Score:1)
You answered your own question. Lots of people are thinking about building the thing from an asteroid. The cable grows from the asteroid until it touches the surface of the Earth. No coiling needed.
It's not realistic to think that a rocket can launch the cable. It's going to be massive - billions of metric tons. No rocket could lift that.
Re:No big uses soon... (Score:1)
Actually, that's not the case.
See here [highliftsystems.com].
Re:No big uses soon... (Score:3, Insightful)
Dear god! (Score:4, Funny)
How do you work with it? (Score:4, Interesting)
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
Re:Nanometers (Score:1)
Re:Nanometers (Score:1)
too expensive, but cool nontheless (Score:3, Funny)
Re:too expensive, but cool nontheless (Score:2, Insightful)
Re:too expensive, but cool nontheless (Score:3, Funny)
All the data you can't understand (Score:3, Informative)
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!
Re:All the data you can't understand (Score:4, Informative)
Checking out the stress-strain curves, the peak is around 160 MPa. A typical modern graphite composite might give you 4 or 5 times higher than that. It just goes to show that high fiber properties are just a portion of the final composite strength.
Another thing I notice about the stress strain curves is the non-linearity. It looks like there is some internal damage maybe happening in the material before failure. This is a concern for repeated loading (fatigue).
umm.... strong? (Score:3, Interesting)
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.
Ultra strong girls blouses? (Score:4, Funny)
igottaask... (Score:2)