Chemical code on the parade

On the morning of October 1, a military parade to celebrate the 70th anniversary of the founding of the people's Republic of China was held in Tiananmen Square, Beijing In the battle field, soldiers of the Third Army march with their heads held high, camouflage chariots rumble forward, and planes roar past With its military prowess, the people's army has shown the world its military strength and achievements in military science and technology At the military parade, all kinds of military equipment with camouflage function "invisible war clothes" appeared on the stage, becoming a powerful scenery So do you know the chemical codes of these "war clothes"? Let's have a look The camouflage clothing of the soldiers is the second skin of the soldiers It is also the robe and armor of the soldiers and an important symbol of the image of the army and the soldiers At the parade, 31 members of the party team appeared in a new "star sky" camouflage suit, attracting everyone's attention It is understood that the pattern color of this camouflage suit is a new design Compared with the past, the camouflage pattern is more delicate Moreover, with the change of the intensity of the ground light, the color will also produce subtle adjustments, with better concealment and anti detection performance At present, the latest camouflage clothing not only uses the color change to form the protective color pattern, but also adds special chemicals such as photochromic polymer materials into the color dye, so that the infrared light reflected by the camouflage clothing is roughly the same as the light reflected by the surrounding scenery, which can not only confuse the enemy's visual detection, but also make it difficult for the enemy's modern detection instrument to capture, with a certain degree The camouflage effect of infrared reconnaissance So, how does photochromic polymer realize the function of color change? Simply speaking, under the action of light or other electromagnetic waves, the chemical structure of this polymer material will have some reversible changes, and the color will change correspondingly from the appearance Photochromic polymer materials are a large family According to the reaction properties, they can be divided into photoisomerization reactions, such as p-dimethylaminoazobenzene, photodifferentiation reactions, such as bis triphenylimidazole, photooxidation recovery reactions, such as sulfurviolet, etc At first, this material was mainly used in optical information storage and other high-tech fields, and then gradually applied to military, anti-counterfeiting and other fields The camouflage clothing with photochromic polymer material has the characteristics of three-dimensional sense of hierarchy, multi-color gradual change, optical illusion and so on It can adapt to the camouflage requirements of forest land, desert, city and other terrain or the battle background with a variety of terrain characteristics mixed In actual combat, the soldiers of special forces not only wear camouflage clothes, but also paint camouflage oil on their faces This is because soldiers are easy to be exposed due to the reflected light of exposed skin when they are concealing After applying military camouflage paint, the skin color is in harmony with the main color of the surrounding environment, so as to avoid the enemy's reconnaissance This military camouflage oil paint is made of special chemicals It is delicate, stable, insoluble in water, safe, non-toxic and non irritating to the skin, and has excellent spreading, covering and adhesion In addition, some military oil paints are added with special chemical ingredients, which can camouflage skin color and prevent mosquito bites Other military oil paints are added with special chemical materials, which can protect soldiers from high temperature burns caused by explosion The soldiers and men of the third army of the "invisible war clothes" of chariots should wear the "invisible war clothes", and large-scale military equipment such as tanks and military vehicles should also wear the "invisible war clothes" After spraying camouflage coating made of special chemical materials, these military equipment can meet the needs of concealment in a variety of environmental backgrounds The main purpose of camouflage is to minimize the differences between military equipment and its surrounding background in optical, thermal infrared, radar wave and other aspects, reduce the probability of being found, and make it difficult for reconnaissance instruments to detect and distinguish Camouflage is an important military camouflage method to improve the use value of various weapons and equipment and carry out self-protection Generally speaking, camouflage coating should meet the functional requirements of color and background, reflection spectrum and background, no light or flat light, weather resistance, wear resistance and chemical resistance At present, the new digital camouflage coating is widely used in China, and its raw materials are composed of base materials, pigments and auxiliary materials The base materials commonly used are nitrile rubber, chloroprene rubber, butyl rubber, polyisobutylene, PVC, polyurethane, etc.; the pigment is generally composed of magnesium oxide, iron oxide, zinc oxide and other metal oxides, as well as conductive materials such as soot, graphite, carbon black, scaly aluminum powder, etc; Auxiliary materials are special materials which can improve the physical and mechanical properties, construction performance and surface state of coatings This digital camouflage coating, combined with the digital camouflage technology, further improves the performance of camouflage color types, chromaticity coordinates, visible light, near-infrared brightness factors, etc., not only further improves the camouflage performance, but also greatly improves the chemical performance and practical performance of the coating, which has the effect of preventing the penetration of toxic agents, which can be said to represent the highest in the field of chemical coatings today Level Fighter's "covert battle suit" soldiers and chariots on land need to be camouflaged, as do those flying in the sky The principle of fighter "stealth" is to use various technologies to weaken radar reflection, infrared radiation and other information, so that the enemy's radar and other electronic detection systems "turn a blind eye" To be exact, the "stealth" of the stealth fighter is only for radar and other electronic detection means, and it is not really invisible to the naked eye In the aspect of anti radar detection, the stealth fighter mainly adopts anti radar camouflage coating, which is a kind of coating that can absorb electromagnetic waves It mainly adopts the mixed conductive coating, that is, the special treated metal oxides such as ferrite are mixed into the adhesive When the radar wave meets this kind of chemical coating containing ferrite, through the change of chemical properties such as magnetism, electricity, light and activation area, the magnetic loss will be increased, which will play the role of absorbing wave, transmitting wave and polarizing wave, so that the fighter can escape the tracking of radar wave and achieve the purpose of stealth In addition to iron oxide, there are also carbonyl iron, ultrafine metal powder, ceramics, radioisotopes, conducting polymers, Schiff base, rare earth elements and other absorbing materials for radar coatings Anti infrared detection is another stealth function of stealth fighter In fact, all objects emit infrared radiation all the time, and the higher the temperature is, the stronger the infrared radiation is The infrared detector is based on this characteristic of infrared The infrared radiation of the aircraft is mainly concentrated in the engine The stealth fighter is coated with ultra-high density carbon absorbing materials on the outside of the engine, which can not only absorb radar waves, but also control the heat emitted from the inside of the engine, so as to escape the search of the infrared detector and make the aircraft invisible The "invisibility cloak" of warships the air force has stealth fighters, and the navy has stealth warships The appearance of stealth warship is a little later than that of stealth fighter At first, stealth technology of stealth fighter was transplanted to warship In addition to radar stealth and infrared stealth, stealth technology of stealth warship should also be used in noise reduction and vibration reduction Because there are many sources of vibration in the ship itself, and it will be excited in the course of navigation and produce strong vibration, which will produce large noise Using the technology of vibration reduction and noise reduction to reduce the noise of warship can improve the concealment and attack and defense ability of warship The noise reduction and stealth technology of stealth warship is realized by controlling the acoustic characteristics of warship to reduce the detection distance and accuracy of enemy sonar system At present, the warships in service in the navies of various countries mostly use diesel engines, which make a lot of noise and are easy to be detected by enemy submarines The invisible warship designed a rubber "coat" for the engine to eliminate the noise of the engine and achieve the purpose of noise reduction and invisibility In the aspect of vibration reduction and isolation, rubber vibration isolators were used before, but in recent years, polyurethane vibration isolators have been gradually replaced because of its low vibration isolation performance and narrow bearing range Based on the excellent dynamic and static mechanical properties and environmental resistance of polyurethane materials, a large number of polyurethane materials for ships have been developed in the world, which are mainly used to reduce the vibration of equipment in ships and maintain the stability of vibration isolators Polyurethane vibration isolator has small damping ratio, good vibration isolation effect in most working conditions, and strong adaptability The influence of vibration frequency, amplitude and fatigue number is smaller than that of rubber vibration isolator In terms of silencing tile, polyurethane silencing tile has a high molecular material of acoustic structure, which can not only absorb the detection sound from the active sonar of the enemy, but also resist the noise of the hull from spreading out, reducing the probability of detection by sonar These chemical materials become an effective means of noise reduction and vibration reduction for submarines, greatly improving the concealment, combat effectiveness and survivability of naval equipment These "invisible battle vests" in various forms are just the tip of the iceberg in the application of chemical materials in military equipment In fact, chemistry is everywhere in the military field The application of black powder and explosive is the sign of human entering the era of thermal weapons Nowadays, chemical science has penetrated into all fields of military It can be said that the development of military science and technology is closely related to chemistry.