Editor's Blog
What do a clown’s makeup and a spinning wheel have in common? Boron nitride is the white material found in clown makeup and face powder. Old meets new as the ancient art of spinning is used to produce a very modern material: a boron nitride nanotube (BNNT) yarn. Researchers have long been able to make nanotubes out of carbon — super-tough carbon nanotube fibers are suitable for weaving into electronic cloth, are four times tougher than spider silk, and 17 times tougher than the Kevlar used in bullet-proof vests. Here’s a video that shows the spinning process for carbon nanotubes:
Creating such fibers from boron nitride has proved elusive. Carbon and boron nitride are about the same strength, but BNNTs can survive temperatures that are twice as high as carbon nanotubes can survive –- 800°C and higher. Up until now, researchers have only been able to create high-quality BNNTs a micron long. Larger versions have been perforated with defects in the crystalline structure.
These problems now appear to be largely resolved. In a recent paper published in Nanotechnology, A team of materials scientists at the NASA Langley Creativity and Innovation Program, the NASA Subsonic Fixed Wing program, DOE’s Jefferson Lab and the Commonwealth of Virginia, describe the ability to create high-quality, uniformly crystalline BNNTs in large quantities. "Other labs can make really good nanotubes that are short or really crummy ones that are long. We’ve developed a technique that makes really good ones that are really long," said Mike Smith, a staff scientist at NASA’s Langley Research Center.*
A cotton-like mass of nanotubes is finger-twisted into a yarn about one millimeter wide. "They’re big and fluffy, textile-like," said Kevin Jordan, a staff electrical engineer at Jefferson Lab. "This means that you can use commercial textile manufacturing and handling techniques to blend them into things like body armor and solar cells and other applications."
The “spinning” process involves a laser aimed at a cake of boron inside a chamber filled with nitrogen. This forms a plume of boron gas that shoots upward. A cooled metal wire is then inserted into the gas, causing the gas to cool and form liquid droplets. The droplets combine with the nitrogen to self-assemble into BNNTs. "It’s like fuel-air-spark in an engine," says NASA aerospace scientist Michael Smith. "The reaction advances violently, creating the superlong tubes in just milliseconds."
Why boron nitride rather than carbon? Building large amounts of inexpensive boron nitride nanotubes opens the door for lighter, faster car frames; affordable space vehicles and ultralightweight armor. Because of their excellent thermal and chemical stability, boron nitride ceramics are traditionally used as parts of high-temperature equipment. Boron nitride has great potential for nanotechnology applications –- BNNTs are more thermally and chemically stable than carbon nanotubes. And BNNTs can be produced with a structure similar to that of carbon nanotubes. However, their properties are very different –- carbon nanotubes can be metallic or semiconducting depending on the rolling direction and radius, whereas BNNT is an electrical insulator with a wide band gap of ~5.5 eV (the same as diamond). Chemical resistance is better for BNNTs, which are able to survive in air up to much higher temperatures. According to ScienceNOW, BNNTs also offer the potential for “pinpoint precision to attack cancer cells by sticking to tumors, absorbing neutrons from a targeted beam, and generating localized alpha radiation to kill the cancer.”
Building large amounts of inexpensive boron nitride nanotubes opens the door for lighter, faster car frames; affordable space vehicles and ultralightweight armor.
"This is the start of a revolution in materials," says Dennis Bushnell, a NASA engineer who has hopes of using BNNTs for space vehicles. "Just about everything can be made lighter, and hopefully, cheaper. You’re talking about energy savings all over the place."
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12 Comments
Been searching for this article for lengthy time in the past and finally discovered here. thanks for sharing this post. value!
Does this mean that it can be used for the space elevator?
My, my. I really had not looked into BNNT’s. I will have to change that.
While I can see where CNT’s are a far more widely useful material due to their electronic properties, I can indeed see enormous numbers of uses for this material. I wonder if it is sufficiently strong enough to replace the current generation of ceramics used for re-entry heat shielding? That they would be highly useful in space based applications in which thermal stability is needed is obvious. Particularly as we continue to make progress towards a space elevator.
Fireproof clothing would also be a theoretical use, especially for firefighters who need mobility as well as heat shielding. Lightweight body armor with superior thermal resistance would make an improvement over the rather cumbersome outfits they wear now, especially if it could be incorporated as part of a HULC or HAL exoskeleton. Firemen would far better able to cope with the hazards of a burning building in a lightweight, fireproof, powered armor suit with self contained breathing apparatus and a cooling system. Many of the dangers of backdraft, collapse, and so-on could be minimized.
Maybe Ozzy will write a new version. I AM FIREMAN!!! *giggle*
I don’t think we want the cord for the space elevator to be conductive.
This is a insulator dear. Not conductive. That’s pointed out in the article
lmao
Great – except that carbon nanotubes, at least long strait ones(they can be made ‘curly’ apparently), are as dangerous to inhale as asbestos particles, for the same reason. They can skewer your cell, and be too long for any cellular waste disposal process to have a hope of removing them. There they interfere with the cells workings and give you cancer (in 30 years). See links:
http://www.scientificamerican.com/article.cfm?id=carbon-nanotube-danger
http://www.newscientist.com/article/dn13946-nanotubes-toxic-effects-similar-to-asbestos.html
http://www.nanotechproject.org/news/archive/mwcnt/
I have read that carbon nanotubes “may theoretically be strong enough” for space elevator under earth gravity. Hopefully even stronger structures can be produced, that would give a nice big margin for error. This is definatly a step in the right direction!
Ah, good. . .you passed the test.
Carry on.
Hate to tell you this hun, but that’s not carbon nanotubes, that’s pretty much the truth for any form of pure carbon.
Look up the dangers of coaldust, soot, lampblack, etc. We’ve been dealing with this “danger” for centuries.
CNT’s however, are not “free floating particles” They are specifically for use in FIXED forms, with each individual tube placed precisely.
So… your post is pointlessly panicmongering, and like too many panicmongers, you simply leap before you look.
Just a quick comment: CNT’s are not free-floating particles but can be released as free-floating particles with wear and tear from a fixed-form application like cable. I doubt that this will be a problem for long, as I’m sure someone will invent an inert cross-linked coating that can not only contain any sloughed-off material, but have some kind of indicator of damage to the structure … if it’s not already on the market … my point is that there is always a legitimate concern for health when new and hazardous materials are used in any application, simple engineering and human factors controls can be implemented to stave off risk
I never thought of this before but if a CNT ribbon was built for a space elevator wouldn’t this thing be charged with a high electrical field due to spanning a long distance through the earths magnetic field? And if so why couldn’t any vehicle traveling on the ribbon not siphon this electricity to use for power rather than beaming power from the ground?
My, my. I really had not looked into BNNT’s. I will have to change that.
While I can see where CNT’s are a far more widely useful material due to their electronic properties, I can indeed see enormous numbers of uses for this material. I wonder if it is sufficiently strong enough to replace the current generation of ceramics used for re-entry heat shielding? That they would be highly useful in space based applications in which thermal stability is needed is obvious. Particularly as we continue to make progress towards a space elevator.
Fireproof clothing would also be a theoretical use, especially for firefighters who need mobility as well as heat shielding. Lightweight body armor with superior thermal resistance would make an improvement over the rather cumbersome outfits they wear now, especially if it could be incorporated as part of a HULC or HAL exoskeleton. Firemen would far better able to cope with the hazards of a burning building in a lightweight, fireproof, powered armor suit with self contained breathing apparatus and a cooling system. Many of the dangers of backdraft, collapse, and so-on could be minimized.
Maybe Ozzy will write a new version. I AM FIREMAN!!! *giggle*
http://www.scientificamerican.com/article.cfm?id=carbon-nanotube-danger
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