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In order to defeat a threat, armor systems are designed to: deform/deflect the threat; dissipate energy; and prevent residual debris penetration. Most anti-ballistic materials used in bullet-proof jackets or explosion-proof blankets are made of Kevlar, Twaron or Dyneema fibers, which stop bullets from penetrating the surface by spreading and absorbing the impact of the bullet’s force. These products were a significant step forward, but often still result in the target suffering from blunt force trauma, severe bruising or damage to vital organs. This is because the force from the bullet reaches the wearer even when the bullet itself is stopped.
Current body armor is great against most rifle, submachine gun, and pistol fire, but it’s far from perfect. It’s heavy, adding as much as 40 pounds to troops’ loads, and it cracks under repeated hits. Against high-velocity and high-caliber rounds, it will typically give way, allowing the rounds to pierce the target anyway.
Researchers are engaged in development on better materials that could dramatically decrease weight while maintaining or increasing the level of protection as well as improve levels of comfort and fit. Because reduced weight would lighten the soldier’s load and increase performance, soldier survivability as a whole could improve significantly. Cost reduction is also a commercial driver, especially when standard body armour systems can be priced as high as several thousand dollars per set. Each of these challenging requirements are being met through
development of new materials, innovative designs and lighter weight systems.
The combat capability of the future soldier will be largely enhanced using nanotechnology. His protective suit will be ultra- light weight and flexible protecting him against all kinds of threats (ballistics, bio, chemical and biochemical agents). Improved nano-properties include reduced weight, higher strength, increased durability, increased reactivity, and the ability to vary or “tune” certain properties. These properties allow for great potential when it comes to reducing the weight of Soldier equipment and improving lethality and survivability.
Research has often focused on graphene’s electronic properties and tensile strength, but this new finding shows graphene’s ability to be stiff, strong, and elastic simultaneously. These characteristics could offer applications in body armor and aerospace shielding.
Beehive
Carbon nanotubes have also been used extensively in the pursuit for nano-bulletproof materials. With a beehive shaped structure and cylindrical nature, these nanotubes have demonstrated incredible strength. They are capped at each end and linked together with covalent bonds to produce nanofibers hundreds of times stronger than steel. The bonds themselves are stronger than those found in diamonds, the hardest substance known to man.
Carbon Nanotubes
A team of researchers from the University of Wollogong have succeeded in developing a new graphene composite material which is stronger than spider silk and Kevlar
Finding the optimal ratio of graphene to carbon nanotubes is a key factor in the development of bullet proof composites. The new graphene composite can be fabricated easily using a wet-spinning method, producing fibers with potential applications in bullet proof armor and reinforcement materials.
RICE & MIT University discover a nanostructured material that could stop bullets
IN 2013, A team of researchers of RICE and MIT University Jae-Hwang Lee, and others have found an extremely light, paper thin nanocomposite material polystyrene-polydimethylsiloxane diblock-copolymer, that could stop bullets as effectively as heavy weight armor like steel.
The team developed a 20 nanometer self assembling polymer which is structured as nanometer thick alternating rubbery layers, providing the reseliance and glassy layers providing the strength. The research was supported by the U.S. Army Research Office.
The team also developed a laser pulse based technique called laser-induced projectile impact test (LIPIT) for producing laboratory scale high speed ballistic impacts and observing their effects precisely. It involves shooting 3 nanometer glass beads at the material at high speed and observing its effects on the material using electron microscope. Using this technique they found that for sufficient high velocities the material melted into a homogeneous liquid that arrested the projectile and sealed its entry path.
The nanomaterial and the testing technology could accelerate the development of applications like materials for vehicle and body armor, protective coatings for satellites to shield from micrometeorite impacts; and coatings for jet engine turbine blades to protect from high-speed impacts by sand or ice particles.
New production technique for high-performance polymer could make for better body armor
A team of researchers has found a new way to produce a polymer material called PBO, a product known commercially as Zylon that’s used in bulletproof vests and other high-performance fabrics. The new approach could be useful in making PBO products that resist degradation, a problem that has plagued PBO-based materials in the past.
“We show that using a nanoparticle catalyst, we can produce PBO in more environmentally friendly conditions and without using a chemical that’s known to cause these materials to degrade unexpectedly,” said Shouheng Sun, a professor of chemistry at Brown University and co-author of a new paper describing the research. “We think this could be a path toward making more robust PBO materials.”
The traditional way to make PBO (its full name is polybenzoxazole) involves the use of polyphosphoric acid (PPA) as both a catalyst for necessary chemical reactions and as a solvent. PPA is a strong, highly corrosive acid and has been pinpointed as the source of PBO degradation. Molecules of the acid become lodged in the polymer chain, leaving the fibers susceptible to degradation when exposed to light and moisture over time. That degradation has led to the recall of PBO-based body armor in the past.
Sun’s lab at Brown has been working extensively with composite nanoparticle catalysts capable of performing the new reactions required to make PBO, and they do so without using PPA. Catalyzing the reactions with nanoparticles would also require less energy and can be performed using renewable formic acid as a hydrogen source. All of that makes the production process greener.
An alloy composition of close to 40 percent gold and 60 percent palladium was shown to be optimal for controlling the rate of reactions needed to make PBO. Particles around 8-nanometers in size produced a reaction speed that maximized the molecular weight of the PBO polymers.
To find out if the PBO was indeed resistant to degradation, the team worked with researchers in Brown’s School of Engineering to perform mechanical testing. Those tests showed that the PBO polymers made with the nanoparticle catalyst were more resistant to degradation than commercially available Zylon — even after being boiled in water and acid for days.
References and resources also include:
https://www.azonano.com/article.aspx?ArticleID=3934
https://www.nanowerk.com/nanotechnology-news2/newsid=53777.php
