Looking for more powerful explosives

  “Boom!” With a loud noise, a sugar refinery in Savannah, Georgia, was wiped out in 2008. The explosion killed 14 people.
  Guess what is the culprit of this accident? sugar! That’s right, it’s a sweet thing to eat!
  I am afraid that few people know that sugar is an explosive. Its explosive power is even four times that of the heavy TNT. This explosion occurred after the fine powdered sugar was accidentally ignited.
  Fortunately, under normal circumstances, you need a lot of fine powdered sugar to pile up together to detonate, so put a hundred hearts on the sugar in your cabinet.
  From yellow to black powder explosives
  Gunpowder is one of the four great inventions in ancient China. As early as a thousand years ago, our ancestors began to use black powder. The component of the explosive action in black powder is saltpeter (chemical name is potassium nitrate). But it was not until the end of the 17th century that British scientists discovered the working principle of black powder by experiment. Since then, human efforts to find better explosives have not stopped.
  After the saltpeter, the explosive that is favored by early blasters is nitroglycerin. But the notoriety of nitroglycerin is that it is very unstable and will explode if given a slight impact. In history, people have thought of many ways to surrender it, and they have paid the price of their lives. It was not until 1864 that the Swedish chemist Alfred Nobel’s nitroglycerin plant exploded. After his brother’s death in the explosion, he continued to test hard to mix nitroglycerin with diatomaceous earth. It is possible to produce a dryer, safer version, although the explosion performance is slightly worse. This kind of explosive is yellow because it contains diatomaceous earth, so it is called yellow explosive. The improved explosives were quickly used to blast mines and tunnels, and to build roads for the construction of railways and canals, making Nobel a rich man.
  The improved explosive safety performance is improved, but at the same time, the explosive power is weakened, far less than nitroglycerin. After the development of TNT and other conventional explosives, although the safety performance continues to improve, but the explosive power has been raised very limited, can not meet the increasingly high requirements of all aspects.
  The demand for more violent explosive power of
  the need for more violent power of explosives, first from military uses. Nuclear bombs are of course powerful and devastating, but everyone knows that nuclear bombs are too destructive and have radioactive pollution that cannot be easily used in local wars. Currently, the most powerful conventional bomb of the US military is called MOAB, which is known as the “mother of all bombs.” It contains more than 8 tons of explosives, which can destroy very solid targets or extensively eliminate ground forces and armor. In 2017, the US military used it to deal with jihadists in the battlefields of Afghanistan.
  However, the military also hopes to use small bombs to equip small drones in the future, requiring bombs to be light in weight, but the power is not lost to large bombs, and existing conventional explosives have not met the requirements.
  If the military demand is scary, let us turn to another peaceful ambition of humanity – space exploration. We know that everything on the planet is constrained by gravity, and the shackles of the gravitational pull of the Earth require a lot of thrust. As early as 1903, after the Russian scientist Tsiolkovsky derived the rocket equation, people have been doing this effort. The core issue that rocket science needs to solve is how to generate a reaction force by injecting explosively expanding gas downwards to propel the rocket into space.
  However, there is a difficulty here: you want to generate more thrust and need more fuel; but the more fuel you carry, the more thrust you need. This contradiction means that if you want the rocket to fly into space, no matter how much conventional explosives you use, it won’t help. The most advanced rockets currently use liquid hydrogen and liquid oxygen mixtures as fuels, which have a higher energy density. Even so, only 2% of the launch weight is the payload (the equipment and systems that the rocket transports are used to perform specific tasks directly), more than 80% of the total is fuel, and the rocket can only reach the weight if it is continuously reduced in flight. track. This is why multi-stage rockets are needed because they can throw empty fuel tanks in time to lift off the load.
  If a better fuel is found, the same size of the rocket can greatly increase the payload, which will greatly save the satellite launch cost, and facilitate the future manned spacecraft to and from the Earth and Mars or the moon base. With better fuels, even rockets and aircraft don’t need to be designed in multiple stages.
  It is these demands that are driving scientists from all over the world to find a new generation of “destructive high-energy materials” that have more explosive power than any previous explosive.
  Unbelievable
  ”The tears of Prince Rupert”
  Let’s first look at a sinuous glass gadget. Its head is a drop-shaped glass ball with a long, curved tail behind it. This stuff seems ordinary and inconspicuous, but it has a nice name called “Prince Rupert’s drops”, a cousin of the seventeenth century King Charles II of England, Rupert. Named after the prince, because the prince first brought it to the UK.
  Why is it able to get this honor? Because it is an incredible thing! This glass thing, you hit it with a hammer, not only can not break, the hammer bounces instead; but if you break its tail, it will instantly break into glass powder. This process, there are video demonstrations on the Internet, interested readers can look for it.
  The physicist explained this: “The tears of Prince Rupert” was formed by the rapid cooling of molten glass into cold water. During the formation process, huge strain energy is stored (the energy formed by the internal tension, such as the tightened spring also has a large strain energy), so even the hammer will bounce down, just like a swell The bulging thing is the same; but after its tail is broken, it is like a balloon leaking, the strain inside can be released instantly, and the shock wave generated makes it break into powder.
  This process has the characteristics of an explosion, but the explosive force is not from the release of chemical energy, but from the release of mechanical energy (strain energy).
  Burning diamonds as fuel – unrealistic
  At the US Army Research Laboratory, Jenny Jenkins and her colleagues have been using nanodiamonds for the same experiment. Diamonds can only be formed under extreme conditions of high temperature and high pressure. In nature, they are generally formed deep in the earth’s mantle. Diamond is a “meta-stable” structure of carbon. That is to say, although it seems to be stable during our lifetime, its stability is slightly worse than that of another form of carbon. On the time scale of the universe, in hundreds of millions of years, they will eventually break into more stable graphite, so don’t believe anything like “Diamonds are long-lasting, one is forever.”
  From a physics point of view, diamonds can be thought of as graphite that stores a large amount of strain energy inside. However, this strain energy is not easy to release, so the diamond is quite stable.

  But if the diamond is very small, it will be easier to break. Clinically, medical researchers have used nanodiamonds to kill cancer cells. They let the nano-diamonds close to the tumor and then use ultraviolet light, which will cause them to rapidly expand and break, thus achieving the purpose of killing cancer cells.
  The experiments done by Jenny Jenkins and others are slightly different. Instead of letting the nano-diamonds burst and explode, they put a lot of nano-diamonds into a hexagonal carbon structure “net pocket” like soccer olefins, applying high pressure; then using The high-power laser blasts the football olefin; thus, the strain energy stored by the elastic football olefin under high pressure is instantaneously released to form the first explosion (this explosion is the release of mechanical energy).
  In the explosion, the shock wave will cause the nano-diamonds in the football to be sputtered at a very high speed like popcorn. When they rub against the air, they burn quickly, producing high-temperature, high-pressure gases; the gas expands rapidly, creating a second explosion (this time the release of chemical energy).
  The equivalent of this kind of explosion is much higher than the equivalent of the current rocket fuel, the hydrogen-oxygen mixture, so in theory, nano-diamond is the ideal material for rocket fuel in the future.
  However, it has been pointed out that to achieve this, high-power lasers are needed to detonate; and if it is to be used on a scale such as rocket fuel, the required laser power is beyond the current state of the art, so this idea is unrealistic. In my opinion, the idea of ​​”burning diamonds” alone is already unrealistic.
  ”Modern version of nitroglycerin” is a
  bit more realistic. They don’t want to make a surprise, they just want to explore the old road honestly. So what is the old road?
  The main component of our currently known chemical explosives, whether it is saltpeter (potassium nitrate), nitroglycerin or TNT (trinitrotoluene), has a characteristic that it contains a large amount of nitrogen. Why do these explosives so favor nitrogen? Because in all molecules, only the nitrogen molecules are connected by two nitrogen atoms through three chemical bonds. We know that energy is stored in chemical bonds. In general, the more chemical bonds, the more energy is stored. When these chemical bonds break, they release considerable energy. Due to the nature of the chemical bonds of nitrogen molecules, the nitrogen content of existing explosives has a significant impact on the explosive power. Nitrogen is an important indicator to measure the power of explosives.
  So, according to this logic, polynitride is an ideal candidate for more powerful: take a group of nitrogen atoms, connect them to a macromolecule, and then break their chemical bonds when needed… So Boom! In theory, the power of polynitride should be more than five times that of TNT.
  This idea is still very down to earth? However, making polynitrides is not an easy task.
  Theories show that they are like diamonds and can only be formed under extreme conditions of high temperature and high pressure. At about 60,000 atmospheres, the gaseous nitrogen will become solid. However, to further produce polynitride, the model shows that at least about 2 million atmospheres are needed! Moreover, there is no guarantee that this polynitride will be stable when the pressure is lowered.
  A team led by Crist, the chief scientist of the US Defense Advanced Research Projects Agency, has been studying how to make polynitrogen compounds since the 1990s. In 2002, they successfully isolated a cation N5+ with five nitrogen atoms. But if you want to go one step further and synthesize pure, electrically neutral polynitride molecules, it will be difficult.
  However, in early 2017, a group led by Professor Hu Bingcheng from Nanjing University of Science and Technology in China reported that they synthesized a considerable amount of polynitride, the total nitrogen anion salt. This all-nitrogen anion salt has a decomposition temperature of up to 116.8 ° C, so it is stable at room temperature, which facilitates application at room temperature. More valuable is that the price of synthetic raw materials is quite low.
  Shortly thereafter, Jenny Jenkins and others at the US Army Research Laboratory synthesized another electrically neutral polynitride in a diamond pressure chamber that produced a large high pressure. This polynitride is a blue liquid with a density three times that of water and 50 times that of liquid hydrogen. In theory, this material can store more energy in the same volume. However, in practical applications, the liquid is unstable at room temperature and explodes in contact with air. At present, this polynitride has a total of only 3 grams and is stored in a low temperature environment of 77K. Its explosive power is not yet tested, because at least 10 grams per test, and it has to be repeated many times. In theory, its explosive power can reach 3 to 10 times that of TNT.
  It can be said that this is a modern version of nitroglycerin – powerful, but it is too dangerous to use directly.
  Perhaps the most powerful “green explosive”
  , polynitride is not the most powerful explosive.
  As early as 1935, scientists predicted that hydrogen also has a metallic state called metal hydrogen. Like diamonds and polynitrogen compounds, metal hydrogen can only form under great temperature and pressure. In nature, the center of a gaseous giant planet such as Jupiter may have conditions for the production of metallic hydrogen.
  Scientists predict that once formed, metal hydrogen can be metastable, even at room temperature and constant strength, to maintain metal characteristics; and most importantly, when it sublimes (directly from solid to gas), the volume expands dramatically. Can produce a violent explosion. The explosive power per 1 gram of metal hydrogen is more than 50 times that of the same quality TNT.
  Earlier in 2017, a team led by Isaac Silvera of Harvard University claimed that they used a diamond anvil to compress solid hydrogen to make a little bit of metal hydrogen. The sample is approximately 15 microns in diameter and a few microns thick. Unfortunately, the anvil suddenly failed, and the tiny sample that was just created disappeared. Of course, other researchers are skeptical about this statement unless the team repeats the experiment.
  Even if it is made of metal hydrogen, figuring out its properties at room temperature and constant strength is also crucial for its large-scale manufacturing.
  If the metal hydrogen is metastable under normal pressure, it will not be easily decomposed once it is formed like a diamond. Then you don’t need to make a lot at first; if you have a sample at room temperature, you have the seed of metal hydrogen. “You can make the sample grow as long as you keep filling the hydrogen, because its surface can adsorb and condense more hydrogen atoms.” Otherwise, it is impossible to achieve the purpose of practical application by making a small amount in the laboratory alone.
  Can it be made into metal hydrogen? Is metal hydrogen stable under normal pressure? All of this is still suspense, and we leave it to the scientists to solve. For us, if metal hydrogen can be used as rocket fuel, the prospects are very attractive.
  First of all, it is the most powerful explosive that scientists can imagine in addition to nuclear bombs. In theory, its power can reach about 35 times that of TNT, and this use is very big. China’s current most powerful 3 ton cruise missile can only be mounted by a 6K strategic bomber. Once the explosive power is increased by 35 times, it means that the weight of the cruise missile can be reduced to the original 1/35 with the same power. The 3 ton cruise missile can even reduce the weight to 100 kg after using metal hydrogen. Within.
  Secondly, if you use metal hydrogen as the rocket fuel, you only need a small rocket of 100 tons to reach the delivery capacity of several tons. At that time, you don’t need a fixed launch tower. You can use the vehicle to carry it at any time and anywhere. The problem of most satellite launches can even allow a single-stage rocket to break through the atmosphere, greatly reducing the difficulty of human exploration of space.

  Finally, it is a very environmentally friendly “green bomb” and fuel. Ordinary rocket fuels, like ammonium perchlorate, produce by-products such as toxic and corrosive hydrochloric acid, so they must be cleaned once every launch in the launch pad area. After the nano-diamond burns, it turns into carbon dioxide. Although carbon dioxide is non-toxic, it is a greenhouse gas. The toxic gas is also released after the polynitride is burned. But the burning of metal hydrogen produces only water vapor.
  What happened to the explosion?
  The explosives used in our lives come from the release of enormous chemical energy in an instant. These chemical energies are originally stored in the chemical bonds of the molecules. When the chemical bonds are broken (such as burning), a large amount of thermal energy is released and high-temperature, high-pressure gas is generated. They work on the outside world with extremely high power and throw the surrounding materials. , compression, etc.; if the gas expands faster than the speed of sound, it will produce a powerful shock wave, causing solid debris to rush out at high speed, hitting people or buildings with great power.
  The explosion is not limited to explosives. In fact, the combustion of gasoline and diesel in internal combustion engines of motor vehicles is also an explosion. After the sparks of fuel vapor, the gas in the internal combustion engine expands sharply, pushing the slide bar to work, and the slide bar drives the wheels to roll forward. explosion. In addition, the rocket also relied on a fuel explosion to lift off. These explosions are achieved by intense combustion and release of chemical energy.
  But the explosion is not just dependent on the release of chemical energy. Explosions like atomic bombs and hydrogen bombs rely on the instantaneous release of nuclear energy; while some explosions rely on even the instantaneous release of mechanical energy. In short, as long as the “huge energy is released in a very short period of time” is satisfied, it can be said that it is an explosion. It is not important as to what energy is released.
  Further Reading
  explosives Brief History of
  explosives originated in China. At the latest in the Tang Dynasty, China has invented black powder. Its active ingredient is potassium nitrate, which is the world’s first explosive. In the Song Dynasty, black powder was used in war. It needed to be ignited by an open fire, and the power of the explosion was not great. In 1831, the British Bickford invented the safety fuse to create convenience for the application of explosives. The more powerful yellow explosive originated in Sweden and was invented by Swedish chemist, engineer and industrialist Nobel.
  In 1846, the Italian Sobrero synthesized nitroglycerin, which is a very explosive liquid explosive, but it is extremely unsafe to use. After 1859, the three sons of Nobel and his son conducted a lot of research on nitroglycerin. They used the “warm method” to surrender nitroglycerin and built it in 1862. However, shortly after the production, the factory exploded, his father was seriously injured, his brother was killed, and the government banned the reconstruction of the factory. In order to reduce the risk of moving nitroglycerin, Nobel had to experiment on a barge on the lake. Once, he stumbled upon the fact that nitroglycerin was adsorbed by dry diatomaceous earth and the mixture was safely transported. In 1865, he invented the thunderbolt detonator and used it with a safety fuse to become a reliable detonation method for advanced explosives such as nitroglycerin. After unremitting efforts, he finally developed a safe and reliable yellow explosive, diatomaceous earth explosive. Subsequently, a more powerful type of explosive, the explosive glue, was developed. About 10 years later, he developed the first nitroglycerin smokeless gunpowder – ballistic explosive.
  Other conventional explosives include TNT, black gold and C4 plastic explosives.
  Many people regard TNT (trinitrotoluene) as a synonym for explosives. In fact, TNT is only the most widely used explosive. It was a powerful and fairly safe explosive invented by the German chemist Wilbrand in 1863. It was widely used in the early 20th century to fill a variety of ammunition and explode. Before the end of World War II, TNT has been the best comprehensive explosive, known as the “king of explosives.” The power of TNT is 14 times that of heavy black powder.
  Hessian was invented by the German Henning in 1899. Before the atomic bomb appeared, it was the most powerful explosive, also known as the “Cyclone Explosive.” After World War II, TNT was replaced by the throne of the King of Explosives.
  C4 Plastic Explosive (C4) is a highly effective explosive agent made of gunpowder (high-performance explosives such as TNT and white phosphorus) mixed with plastic. If you attach an adhesive material to the outside, you can stick it like a chewing gum, so it is called “cruel gum.” This type of explosive can easily escape the X-ray examination, and it is difficult for a police dog without specific olfactory training to recognize it. It is these two points that have made terrorists more aware of it. In recent years, several incidents of assassination with C4 plastic explosives have occurred. For example, at a banquet in Iraq in 2013, a female killer was made of C4 plastic explosives. Assassinate the incident together.
  Diamond anvil
  which is a small laboratory apparatus for producing pressure. It consists of two pointed-to-point diamonds. Place the sample between the two tips and then constantly reduce the distance between the two tips. Since the contact faces of the two diamonds are small, and the area of ​​the externally pressurized portion is large, the final pressure is concentrated on the two pointed ends of the diamond. This allows the pressurized portion of the sample to achieve a high pressure of approximately 1 million atmospheres – the limit of the high pressure currently available to manpower.