Bulletproof T-shirts?

ResearchBlogging.orgWhile it might sound science fiction or comic book fodder, scientists have actually developed a kind of wearable protective cloth from T-shirts that contains the same ultra-strong material used to armor tanks.

ResearchBlogging.orgModern high-impact military vehicles and bulletproof vests are reinforced with a substance called boron carbide. It's the third hardest material known to man at room temperature, with a hardness of 9.3 on the mohs scale, just a hair behind diamond's hardness of 10. It's hard to imagine how such a rigid material could be comfortable to wear, but scientists have recently developed the technology to use cotton T-shirts to create boron carbide nanowire cloth.

i-8bee6b28678575c3c9eea2992a7b6bb5-nfig001-thumb-250x209-46908.jpgTo turn cotton bulletproof, researchers from the University of South Carolina and their collaborators from China and Switzerland dipped sections of regular T-shirts (Fig 1a) in a special mix of nickel and borate. After allowing the cotton to absorb the mix for 2 hours (Fig 1b), the textile was dried quickly in an oven and cured at a high temperature for 3 hours. Once ready, the pieces of cotton were placed in a furnace and headed at 1160°C for 4 hours while continuously aerated with argon. Finally, the resulting fabric pieces (Fig 1c) were cooled and analyzed using electron microscopes and a barrage of strength tests.

You can see in Fig 1d what the material looked like once it was made. Figures 1e and 1f are further Scanning Electron Microscope (SEM) images of the nanowires themselves, and figures 1g and 1h are Transmission Electron Microscop (TEM) images. Lastly, figure 1i is a cartoon of the cross-sectional structure of the boron carbide nanowires.

The end result was a fairly elastic and flexible fabric with the strength of boron carbide but the flexibility of cloth.

"The boron-carbide nanowires we synthesized keep the same strength and stiffness of the bulk boron carbide but have super-elasticity," explained Xiaodong Li co-author of the recent paper which published online first in Advanced Materials.The researchers are hopeful that this new technique will revolutionize not only personal body armor but also the protective coating on planes, tanks and other military vehicles. "We should be able to fabricate much tougher body armors using this new technique. It could even be used to produce lightweight, fuel-efficient cars and aircrafts."

Although the scientists have high hopes for their nanowires, the new tech isn't ready to replace Kevlar in bulletproof vests any time soon. The actual performance of the material wasn't quite as high as they had hoped, and further refinement of the technique will be necessary before it can replace current body armor materials. Still, the idea that T-shirts may be the future of bulletproofing is incredible!

Tao, X., Dong, L., Wang, X., Zhang, W., Nelson, B., & Li, X. (2010). B4C-Nanowires/Carbon-Microfiber Hybrid Structures and Composites from Cotton T-shirts Advanced Materials DOI: 10.1002/adma.200903071


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Hmm, interesting but think what it would do to your sewing machine needle! I wonder if it would require some sort of special technique to actually sew it into something.

Shouldn't be too much of an issue with a sewing needle. Precise penetration between threads is quite different from blunt application of high energy.

Speaking of which, without the stiffness I'm relatively confident the bullet would do enough damage from the kinetic energy alone (no penetration) to seriously wound or possibly kill regardless.

Good point Mike. If you are wearing a flexible shirt like this and get shot it may not technically penetrate the shirt but the shirt+bullet will still penetrate your skin. I wonder if the application would be more for a soft fabric outer coating on a more rigid vest.

I wondered about that watching one of the Lord Of The Rings movies. Frodo (I think) had some kind of thin, silken shirt that would protect him from anything. When a giant tried to stab him with a huge spear, he survived.

Apparently it's best (or so I was informed) not to speculate about such things while watching a movie.

hopefully the makers of this shirt don't get any lawsuits when people try to shoot themselves with their shirt on and die...

This will be useful as personal body armor for about two seconds. Until people start putting steel needles in the middle of the bullets. Tanks and such, probably will work better.

Frodo (I think) had some kind of thin, silken shirt that would protect him from anything.

Well, not exactly. The shirt was made of mithril, also known as "truesilver", which was a metallic substance. I believe it was basically a mail shirt, but particularly light and thin. Not as light as fabric, however.

Well, that's why dilatant properties are so useful. Back the boron carbide cloth with something that increases rapidly in viscosity when stressed, like d3o.

I live in South Africa. I want one! How reassuring it would be. I wouldn't be surprised if it were only good for quite small calibres. But I guess that's what a private citizen would want one for - to avoid pointlessly losing your life to a hand-gun.

It's highly unlikely, imo, that criminals would obtain armour piercing rounds to counter armour like this. After all, they always risk encounters with armoured police and have not so far begun using AP rounds.

In South Africa, organised criminals in cash-in-transit heists use rifles. But for the kind of crime you're most at risk from, it's hand-guns.

I'd rather have a broken rib and a bit of ruptured tissue compared to a great big hole right through me.

The point made earlier about needles going through the fabric without much difficulty brings to mind another issue. The ability of a bulletproof vest to stop a bullet does not mean it will stop any sort of attack. In fact, the "Weird News" collections often include stories about someone who decides to test their bulletproof vest by having someone attempt to stab them. Guess what? Knives can go through Kevlar better than bullets, in many cases, and the test winds up with the vest-wearer dead.

Be interesting to know if boron carbide fabric has the same drawback; I suspect it would.

And, as someone else mentioned, just because a bullet doesn't penetrate doesn't mean it won't do serious damage; you're still talking about a lot of momentum in a small object.

This will be useful as personal body armor for about two seconds. Until people start putting steel needles in the middle of the bullets.

armor-piercing ammo; invented as such, oh, almost a century ago i think. available to military and law enforcement easily enough, but (in the USA) only available to regular civilians in rifle ammunition, not for handguns. the logic behind that is that high-power rifles (which is most of them) can punch through most forms of body armor anyway. handguns usually can't, and most body armor is meant to stop mainly handgun rounds in any event.

and yes, the issue of deforming armor enough to kill the wearer even without penetration is quite real. body armor is usually tested by wrapping it around a clay or ballistic gelatin form before shooting it, since armor often depends on your body to deform with it to dissipate the bullet's energy; shooting armor when it's empty, or wrapped around something too soft or too hard, doesn't make a fair test. seeing photos of clay forms with six-inch-deep craters in them where a shotgun slug dented the armor makes for disquieting thoughts.

By Nomen Nescio (not verified) on 14 Apr 2010 #permalink

This is a very interesting development. I haven't been following armor technology very actively for years now, but when ultra-hard nanofibres (e.g. aggregated diamond nanorods and tungsten sulfide nanotubes) first started popping up I knew it was just a matter of time before cheaper, quicker production methods would be devised. With news like this, we're getting closer and closer to that point.

If thin, flexible and incredibly tough materials do break through in a big way, the effect on warfare will be very significant. Together with smart materials that can turn rigid quickly enough to react to a supersonic projectile impact, this would mean complete bodysuits capable of defeating most common types of small arms threats as well as providing excellent protection against fragmentation. We live in exiting times for terminal ballistics.

As for body armor in general, there's plenty of actual science out there, if people here are interested. In particular, the National Institute of Justice publishes a commonly used standard for Ballistic Resistance of Body Armor (currently at version 0101.06), along with Stab Resistance of Personal Body armor (0115.00). Skimming through these, with plenty of cross-referencing from Wikipedia if you're new to the subject, should help with understanding what makes for good body armor, and what their limitations are.

The Kevlar Survivors' Club also makes for interesting reading, and demonstrates exactly how good this stuff is at protecting people from all kinds of threats. Just in case someone thinks knives, hammers or shotguns somehow render body armor moot.

And as for armor-piercing ammunition, there is indeed plenty of it around, in the military at least. Common rifle caliber ammunition with subcaliber tungsten carbide cores (e.g. US M993 and M995 for 7.62mm and 5.56mm NATO) can defeat many types of body armor, even some of the ones with boron carbide plates -- so one would assume boron in T-shirt form wouldn't fare too well. Hell, assault rifles capable of defeating any conceivable body armor for at least the next 15 years already existed back in 1989.

But the fact that it is possible to penetrate such armor doesn't make the armor _useless_, just like the existence of warhammers did not make plate armor useless in a 15th century melee. Compared to no body armor, when anyone with a deer rifle can crush a hole yay big in your thorax at 300 meters, being able to force your enemies to use very expensive, hard to get ammunition just to be able to seriously threaten you is a massive advantage.

Like most things combat-related, terminal ballistics is a subject where one is better off not trusting random net people. Guns pretty much anywhere on the internet is like evolution on AnswersInGenesis. Plenty of netizens have firm beliefs on such matters, formed purely out of third-hand anecdotes and ridiculously inaccurate media portrayals. For all you know that might include me, so Google away.

By Grim Redeemer (not verified) on 14 Apr 2010 #permalink

Hrmmm...I think I'll stick with wearing Dragon Skin on my everyday me-versus-bullet excursions.

Are the nanofibres likely to break off and migrate into the skin during wear? There are some real concerns about nano-particles in cosmetics at present, regarding their absorbtion into human tissue.

It doesnt matter if the blunt force would break ribs, getting shot is getting shot and if Im going to get shot against my will, I will take every advantage I can get. I have read police reports of women getting shot 6 times in the chest, point blank with .45acp ball ammo and still surviving. She had a collapsed lung due to deep penetration and still lived...if she had a bullet proof or resistant tshirt the penetration would not have been nearly as deep. For hangun rounds this is a great idea, get shot sucks and Ill take somthing over NOTHING!