Will the Armocom Center start using nanotechnologies, which today, as they say, are widely known in the manufacture of personal protective equipment? Is it even possible to effectively use them in this area? These and other questions of the Krasnaya Zvezda correspondent are answered by the general director of the Arkomok Center for High-Strength Materials, the winner of the USSR State Prize and the RF Government Prize, Professor Evgeny KHARCHENKO.
- Yevgeny Fyodorovich, for a start, help determine the concepts. What are nanomaterials and nanotechnologies that have been talked about so much lately?
- By nano-substances usually imply small particles, the size of which is smaller than 0,1 micron (micron is 0,001 millimeter), that is, does not exceed 100 nanometers. In the simplest representation, it is a finely ground powder. For example, many paints are nano-substances, since the pigments in them are crushed to very small sizes. However, the most common nanoparticles that are specifically grown in a gaseous environment are carbon nanotubes. They got this name because these small particles are several times longer than the diameter. Although in shape they can be fibers.
The world's carbon nanotubes are widely used, there is enough information about this ...
- Have you tried to use non-substances for the manufacture of personal protective equipment?
- The basis of all body armor equipment is aramid fiber. Its diameter is about 12 microns, which is 1 / 6 of the diameter of a human hair. Due to the small diameter and special structure of its molecules, it has a very high strength and lightness. Today, conventional aramid fiber with a 1 section of mm2 is able to withstand 500 kg load.
- Do you mean longitudinal stress?
- Yes. In the transverse direction, this fiber does not hold the tensile load as well as in the longitudinal direction, and if it is tied in a knot, the strength will be reduced by half. Nevertheless, it will hold a quarter of a ton, which, you see, is also a lot.
Threads are made of these fibers, fabrics are made of threads, helmets and body armor are formed from fabrics.
- Is this just Russian technology or do personal protective equipment in the same way abroad?
- Not all countries have this technology. But where there is this technology, it is not much different from ours. True, the final product is different in its characteristics everywhere ...
- Can this product be improved through the use of nanomaterials?
- In Mytishchi, at the “Heat-resistant Textile Research and Production Enterprise”, which is headed by Igor Vladimirovich Tikhonov and which produces aramid fibers, several years ago we tried to connect carbon nanotubes with aramid fibers. Fiber is a collection of very small fibrils, or packs of macromolecules. There are no chemical bonds between the fibrils, because all the molecular chains run along the fiber axis, therefore it does not have a large transverse strength. So, at the fiber spinning stage, we tried to introduce nanoparticles into them, assuming that these particles, as if holding the longitudinal fibrils together with bricks, would improve the properties of the fibers, ensuring transverse strength. The bullet hits across the fibers.
- The hypothesis was confirmed?
“As a result, on the samples we obtained an 20-percent increase in strength and about a quarter increase in the elastic modulus, that is, the stiffness that does not allow the fiber to stretch (the ability of the fiber to stretch, but withstand a large load, is called strength. - Auto.) . Thus, we have seen the main point: there are great opportunities in this direction, but it is extremely technologically complex. After all, it is necessary with the utmost clarity to choose the sizes of nano-additives, their very precise concentration, the stage of introduction into the fiber in the process of its formation ...
On this point of view, in practical terms, we suspended the case and put the obtained results in reserve, now clearly presenting the existence of such a method.
- How can the use of aramid fibers reinforced with nanoparticles affect the performance of personal protective equipment?
- The stronger the unit cell of the protective equipment, that is, the fiber (and millions of fibers in a bulletproof vest), the greater the chances of obtaining the best protective properties. Body armor can be made thinner and lighter while maintaining the same class of protection. Or, while maintaining weight and size, increase the level of protection.
“Why did you put aside the results of your research?”
- As I have already said, to create advanced materials on their basis is very difficult technologically. This requires great effort and money. The technology of mass production of nanofibers, whose diameter is hundreds of times smaller than that of aramid polymers, is not yet available. The existing technology, which is used in pilot production, is very expensive.
In general, in applied science it happens that it is expedient (or necessary) to leave some innovative ideas for later. As for fundamental research, our Armokom center is still not the Academy of Sciences.
“Since you and your colleagues have established that nanomaterials are capable of enhancing the protective properties of body armor and helmets, will it be appropriate to postpone the use of these materials to protect the lives of our soldiers and officers?” And if tomorrow is war, if tomorrow is a hike?
- To this day, more than half of the army wears steel helmets of the 1968 model of the year! Everything costs money ... Recently we began to massively supply 6B7-1М helmets from the new materials to the Ministry of Defense. They were created on the instructions of the Main Directorate of the Ministry of Defense of the Russian Federation when they were led by generals Nikolai Svertilov and the head of the department Boris Ruchkin. We manufacture these helmets from aramid composite materials. If we began to make them using nanosubstances, they would become twice as expensive, although at the same time, perhaps, percent on 20 is easier.
However, for this, you first need to completely refine the technology. So far we have only shown the fundamental possibility of improving the protective properties of aramid armor through the use of nano-substances. Fundamental research is needed in this area.
- It turns out that the locomotive of the domestic production of personal protective equipment - the Arkomok center is now forced to stop?
- No, we do not stand still and continue to improve personal protective equipment for our fighters. We have developed a new helmet for equipping a fighter according to the “Warrior” program and a new protective kit for the crews of combat vehicles. Compared to the 6B7-1M helmet, this helmet is lighter by almost a third, it weighs only 1 kg. It has the same level of protective properties as its predecessor. Reducing the mass of the helmet without loss in the class of protection is very important for the soldier, since night vision equipment, radio communication equipment, etc. should be placed on the helmet.
Preliminary tests of the helmet have been successfully completed, state tests are now underway, and I hope the army will receive it next year as part of the Ratnik outfit.
- As I understand it, you managed to reduce the weight of the helmet without using nanotechnology?
- Yes, we used in this case the possibilities of fiber-composite technology and constructive technologies of our enterprise for the manufacture of products.
- Is it possible that you postpone the topic of nanotechnology in individual means of protection for the future, and in other technologically and technologically advanced countries, for example in the USA, they will invest huge amounts of money in this direction, and as a result Russia will not happened in storiesagain have to catch up?
- This is if the Americans do something. And if not? Can you imagine at what level - almost at the molecular (!) - it is necessary to improve the material, which already has a fairly perfect structure. By the way, American Kevlar is still significantly inferior to our “Ruslan”. Fabrics from domestic aramid fibers possess unsurpassed ballistic characteristics, this has been proven experimentally (read more about this in the article “Golden Helmet for the Queen of the Fields”, published in the December 7 Red Star 2011 of the Year. - Auth.). So while our overseas colleagues are in the role of catching up in the production of ballistic aramid fibers. And the use of nanotechnology to enhance them is the next, even more difficult level.
- Evgeny Fedorovich, at the beginning of our conversation you gave an example of the use of nanoparticles in paints ...
- It is obvious that the dyeing of the uniform of a soldier is of great importance on the battlefield. A soldier must always merge with the terrain, so any armored suit must be camouflaged. In particular, a protective kit for the crew of combat vehicles, which we developed and produce for the Armed Forces. Indeed, in the event of a hit tank or IFV crew, if left alive, leaves the car, and it is important for him to immediately merge with the environment.
It is also obvious that this kit should not burn. And to make it incombustible, we used fibers of special fire resistance for the production of the fabric from which the sets are made. But the trouble - these fibers, this fabric did not take the dye. That is, after painting faded under the sun for three to four days (in the photo on the right). But when they began to apply nano-dyes, which penetrate into the structure of the fibers themselves and are fixed there, the coloring became stable and did not burn out in the sun (in the photo on the left). At the same time, the flame retardant properties of the fabric did not decrease.
- What colors can be painted uniform nanokrakraski?
- In different. For example, in white, which allows the fighter to merge with the terrain in winter.
- Are there any other areas of application of nanomaterials in the production of personal protective equipment?
- There is. The most effective armor to date - composite ceramic. It consists of a very solid screen made of ceramic (boron carbide, silicon carbide, aluminum oxide) and a substrate of aramid organoplastic. On the screen, comparable in hardness to diamond, a bullet is shattered (in the picture - what remains of the bullet after it gets into ceramic armor). These broken pieces have enormous kinetic energy, but they are effectively absorbed by the aramid substrate.
The total specific weight of the composite ceramic armor is 2,5 g / cm2. And steel armor of the same class of protection is about 8 g / cm2, that is, more than three times heavier. True, steel has a slightly higher survivability, and the second bullet, hitting almost the same place in a steel bulletproof vest as the first one, may not pierce it. But show me the shooter who, from an assault rifle in a feverish battle at a distance of 100 and more than a meter, will put two bullets or the entire automaton burst into a cigarette pack! In real combat with the use of the now existing mass rifle weapons it is almost impossible. So the advantage of personal protective equipment made of composite-ceramic armor in less weight is undoubted. Agree, there is a difference: wear a chest panel weighing 3,2 kg of steel or 1,7-kilogram of composite ceramics.
- I agree, especially since in battle one of the main conditions for survival and achievement of victory is the maneuverability of forces and means. Protected by heavy armor, but at the same time a barely moving soldier is a convenient target for the enemy.
- And composite ceramic armor, protecting against all handguns, including from armor-piercing incendiary bullets of caliber 7,62 mm, at the same time, due to its lightness, allows to maintain maneuverability. However, there is a small nuance - it is not easy to make this pottery. In order to obtain a uniform and durable ceramic material, it must be very carefully, at the nanoscale level, crushed at the production stage. Then it dries, burns and gains amazing hardness. The smaller the original products of this ceramics - and in a simplified representation this is clay, although it is special, in which several components are mixed, the better protective properties will be provided by its products. And we produce products with such ceramics.