The year 1846 became a turning point at the junction of two eras of European civilization: chemists and humanists proposed replacing the good old black gunpowder with two creatures of hell - nitroglycerin and nitrocellulose. The first gave the world dynamite and nitroglycerin gunpowder, the second - high explosive pyroxylin and pyroxylin gunpowder. As a result, the war finally lost its flair of romance and gentlemanliness.
Yuri Veremeev
In 1905, shells from naval guns of 6 inches and larger caliber were stuffed with pyroxylin. Yellow color indicates a charge made from wet (10%) pyroxylin, dark yellow indicates an intermediate detonator made from dry (5%) pyroxylin. The fuse socket is located in the screw bottom of the projectile. This design was determined by the fact that the pyroxylin charge was made according to the shape and size of the internal cavity, inserted into the projectile, and then the bottom was screwed in
During the First World War, pyroxylin was already used only where complete tightness could be ensured - mainly in torpedoes and sea mines
In the First World War, most European countries abandoned the use of pyroxylin as an explosive filling for shells, opting for the poisonous, but safer in the manufacture of picric acid
Pyroxylin in shells remained only in Russia and Switzerland. And only because large reserves of this substance have been accumulated
In 1832, the chemist Braccono decided to see what would happen if nitric acid was used to attack the starch and fiber that make up wood. The acid dissolved these substances well, and when water was added to the solution, a precipitate formed. When dried, it was a powder that burned very well. The Parisian chemist Pelouz (later Nobel’s teacher) became interested in Braccono’s experiments. But, like Braccono, Pelouz did not attach any importance to the discovery of nitrocellulose. This substance was officially reported by the German chemist Christian Friedrich Schönbein in March 1846 at a meeting of the Basel Society; He called the resulting version of nitrocellulose pyroxylin.
First steps
They say that Shenbein invented pyroxylin by accident. After spilling nitric acid in the laboratory, he allegedly wiped up the puddle with his wife’s cotton apron, and then hung it up to dry by the stove. Once dry, the apron exploded. But this is a legend.
In fact, Schönbein was engaged in research on nitrocellulose purposefully, and this version was called Schiebaumwolle (“shooting cotton”; the name remained with pyroxylin in German). And although it was Shenbein who discovered the ability of pyroxylin to explode, his goal was to replace black smoky powder (at present, pyroxylin, along with nitroglycerin, remains the main component of smokeless powder).
When Schönbein made his famous report, the first gun shots with a new type of gunpowder had already been fired at the Kummersdorf training ground. It seemed that the world was on the verge of industrial production of pyroxylin gunpowder. But from the very beginning, pyroxylin, like nitroglycerin, showed its devilish character and rebellion. Making new gunpowder turned out to be just as dangerous as making nitroglycerin. Pyroxylin workshops exploded one after another.
The pyroxylin baton was taken over from Schönbein by the Austrian artilleryman Lenk, who determined that only a poorly washed product decomposes and explodes during storage. But it was too late: the Austrian emperor banned experiments with this dangerous substance. The work was continued in 1862 by the Englishman Friedrich Abel, who in 1868 managed to obtain pressed pyroxylin. The method was reminiscent of paper production. When wet, pyroxylin is completely safe. Abel crushed it in water, after which he formed sheets, bars and checkers. Then the water was squeezed out.
These products could already be used as high explosives. But commercial success was undermined by competition from the newly introduced Nobel dynamite, which was much more powerful than pyroxylin and much cheaper.
Safe explosive
Pyroxylin was appreciated only by the military, whose requirements for explosives were very different from the requirements for commercial use. Pyroxylin is stable in storage, does not decompose, and such dangerous nitroglycerin is not released from it, like from dynamite. Pyroxylin can be stored for decades without the slightest change, which means it is possible to create the necessary supply of shells in advance in case of war. The properties of pyroxylin are not affected by frost, while frozen dynamite becomes very dangerous. When wet, pyroxylin can be screwed, cut, sawed, or shaped into any shape—a property that is especially valuable for use in projectiles. It can be pressed, squeezing the water out of it and bringing it to the desired degree of sensitivity.
From an open flame, pyroxylin only ignites and burns without explosion, which is especially valuable on ships. After all, even black powder sent many ships to the bottom. Even in the days of the sailing fleet, the cruise chamber (the compartment of the ship where gunpowder was stored) was the most protected place from fire and the slightest spark.
Pyroxylin usually does not explode when shot by a bullet, while dynamite does so more than willingly. This property, completely insignificant for commercial explosives, has become extremely important in military applications.
Capricious competitor
In the last quarter of the 19th century, artillery shells, naval torpedoes and mines began to be filled with pyroxylin. However, with the advent of TNT and melinite, pyroxylin quickly disappeared from the arena. But why? The fact is that, despite all its positive qualities, pyroxylin is still significantly inferior to melinite, and especially TNT, in ease of use, safety and preservation.
First of all, pyroxylin is very capricious in terms of humidity. At a humidity of about 50% or more, it completely loses its explosive properties. On the other hand, when the moisture content drops below 3%, the pyroxylin “dries out” and begins to decompose. At a humidity of 5-7%, pyroxylin readily explodes from a standard detonator capsule No. 8; at 10-30%, an intermediate detonator is required for an explosion - a block of pyroxylin with a humidity of 5-7%. Such a strong dependence of explosives on humidity required constant and careful monitoring and the creation of special conditions. Even in warehouse conditions, this task is very difficult: you need warm rooms with good ventilation, with air dehumidifiers, which is often impossible to provide in front-line conditions.
The situation was partially resolved this way: after manufacturing, the checkers were brought to the required humidity, and then carefully covered with a layer of paraffin. However, even in this case, careful control was required. The dependence of pyroxylin on humidity played a cruel joke on the Russian squadron, which in 1905 sailed from Kronstadt to the rescue of Port Arthur, besieged by the Japanese.
Sinister contribution
Everyone believed that the pyroxylin in the shells was sufficiently protected from moisture. However, for safety reasons, the shells were stored without fuses, and moisture penetrated into the pyroxylin through the fuses. And in conditions of many months of sailing across two oceans, it was simply impossible to maintain the required humidity.
The Japanese shells were equipped with the then newfangled melinite, called shimose after the name of the inventor (Shimoze). Melinite is completely insensitive to dampness and explodes reliably in any conditions. In addition, when a shimosa explodes, a large amount of poisonous gases with a suffocating effect is released, in fact, a real chemical warfare agent.
After the Battle of Tsushima in Russia, it was fashionable to blame for this severe defeat at sea, unprecedented for the Russian navy, “mediocre admirals, stuck in the era of the sailing fleet,” “evil officers,” whose “only means of training and educating sailors was the fist ", incompetent royal shipbuilders. But a careful examination by specialists of the combat maneuver schemes of both squadrons each time led to the conclusion that Admiral Rozhdestvensky did not make significant mistakes, and the level of design of the Russian ships was approximately equal to the Japanese ones. But more than 60% of the shells filled with damp pyroxylin did not explode when they hit Japanese ships, while the Japanese ones, with shimosa, exploded when they hit the water, showering Russian sailors with fragments and enveloping them in poisonous gases.
Many historians, without bothering to study the design of the shells, argue that the explosive charge of Russian shells was too small. In fact, the Japanese, not having enough armor-piercing shells, simply shot with what they had - mostly high-explosive fragmentation shells, the charge of which was, naturally, much larger. Other authors blame the supposedly bad fuses of Russian shells, not knowing that the fuse of an armor-piercing shell should fire with a delay when the shell penetrates the armored space, where the explosion is especially destructive and terrible, since it destroys the mechanisms and destroys the crew. It is worth noting that the “Filimonov pipe” of the 1884 model, reviled after Tsushima, subsequently proved itself to be excellent during the First World War.
Japanese "shimozas", exploding at the sides and on the decks of Russian ships, incapacitated sailors on the decks, destroyed superstructures and caused fires, but if not for damp pyroxylin, then the explosions of Russian armor-piercing shells inside vital compartments protected by armor would have caused much more terrible destruction. And although pyroxylin in Russian shells was not the only or even the main reason for the defeat, it made a fairly significant contribution to the tragedy of the Russian fleet.
This was one of the reasons that pyroxylin began to disappear from the stage very quickly. As the patriarch of explosives, the German professor Kast, wrote in his book Spreng und Zuendstoffe, published in 1921 in Berlin, already during the First World War, pyroxylin was used only in torpedoes and sea mines (where complete tightness was ensured), and only in Switzerland and Russia used it in shells of large calibers (152-210 mm), and only because at one time too large reserves of them were created.
Russian way
Why did pyroxylin turn out to be a more popular high explosive in Russia than in European countries? Why did both Japan and Europe choose to use poisonous picric acid (melinite)? Everyone who worked with melinitis noted that within a few hours headaches, shortness of breath, rapid heartbeat and even loss of consciousness were observed.
Ironically, one of the culprits of the Tsushima defeat turned out to be the great Russian chemist D.I. Mendeleev. He solved the main problem of making pyroxylin - how to make it dry safely. The great Russian chemist proposed dehydrating pyroxylin with alcohol, after which the alcohol evaporated on its own in the open air. In this way, the most dangerous stage was avoided, and already in 1880, according to the project of M. Cheltsov and naval lieutenant Fedorov, a plant for the production of pyroxylin using the Mendeleev method was launched.
First of all, this explosive was needed by the navy, where by this time there had been a clear discrepancy between the power of battleships and the range of naval guns with the lethality of shells filled with black powder. Thus, at this moment Russia was ahead of Europe in artillery affairs.
In addition, Colonel A.R. Shulyachenko, studying the properties of dynamite in 1876, came to the conclusion that its use in sapping was dangerous due to its tendency to detonate from an air shock wave during close explosions of other charges or artillery shells. According to his proposal, back in 1896, the Russian military engineering department decided to exclude dynamite from the explosive materials supply sheets for sapper battalions and replace it with pyroxylin.
In Europe, where attempts to produce pyroxylin began much earlier than in Russia, and where numerous explosions of pyroxylin production took place, these explosives were treated with distrust and preferred to begin production of picric acid, albeit poisonous, but safe to make (in England in 1888 under the name "lyddite", in France in 1886 under the name "melinite"). However, it cannot be said that pyroxylin was not used at all in Europe.
In England, the so-called tonite was made (a mixture of 51% pyroxylin and 49% barium nitrate). This explosive was used as a sapper and in naval demolition cartridges. Belgian tonite contained 50% pyroxylin, 38% barium nitrate and 12% potassium nitrate. And during the First World War, the British made sengit (50% pyroxylin and 50% sodium nitrate).
In Russia, mass production of pyroxylin began in 1880 and large reserves were accumulated, so during the First World War it was used as sapper explosives. Pyroxylin was supplied to the troops in the form of pressed blocks that looked like hexagonal prisms. The large checker (250−280 g) had a height of 50.8 mm and fit into a circle with a diameter of 82 mm, the small checker (120 g) was 47 mm and 53 mm, respectively. So-called drill blocks (56 g, 70 mm high) were also made, the diameter of which coincided with the diameter of the hole punched by the drill in the stone (30 mm). They were used to crush stone and loosen frozen soil.
All these checkers were divided into ignition and working ones. The first contained 5% moisture and had drilled holes for the detonator cap. For the latter, the humidity reached 20-30%, and they did not have slots for detonator capsules. The charge was made from working blocks, and one ignition block was placed in its center. The incendiary tube (a detonator capsule with a piece of fuse cord) was inserted into it - this ensured the safety of blasting operations. And yet, the time of pyroxylin was already running out; it was being replaced by melinite and TNT.
Today, few people remember about pyroxylin, with the exception of historians studying the military events of the late 19th and early 20th centuries. The author came across the latest mentions of pyroxylin in the Soviet manual on enemy mine explosives, published in 1943, where it is written that Italian sappers on the Soviet-German front used cylindrical bombs (weighing 30 g, diameter 3 cm and length 4 cm) made of dry pyroxylin, wrapped in paraffin paper. The Finnish army used cylindrical charges made of wet pyroxylin as demolitions. The coincidence of sizes suggests that these were explosive charges removed from obsolete large-caliber artillery shells of the tsarist army. The Red Army apparently last used pyroxylin as a sapper explosive at the beginning of World War II. This is mentioned in the Soviet book on explosive means, published in 1941, and in the German leaflet on captured mine-explosive means, published in January 1942. Judging by the shape and size of the checkers, these were also remnants of pre-revolutionary pyroxylin stocks.
A.A. Corned beef Laboratory preparation of explosives. Manual for practical exercises in the laboratory (1925)Methodology:
Pyroxylin is obtained by the action of nitric acid HNO 3 on fiber (C 6 H 10 O 5) x. For laboratory experiments, you can take cotton wool; to enhance the effect of nitric acid, add sulfuric acid H 2 SO 4 the effect of sulfuric acid is primarily explained by the fact that the latter removes water from the circle of interaction of nitric acid on fiber; depending on the strength of the acids, their ratio to the amount of fiber, etc., pyroxylins are obtained containing varying amounts of nitrogen.
Taking x=4 according to Viel, i.e., C 24 H 40 O 20, the effect of nitric acid can be expressed by the following equations:
C 24 H 40 O 20 + 12 HNO 3 = C 24 H 28 O 8 (ONO 2) 12 + 12 H 2 O
C 24 H 40 O 20 + 11 HNO 3 = C 24 H 29 O 9 (ONO 2) 11 + 11 H 2 O, etc.
We will, if possible, carry out the laboratory preparation of loose pyroxylin under the same conditions as it is produced in Russian factories; Let us describe the production of 2 types of pyroxylin: insoluble and soluble, a mixture of which is currently used for the manufacture of smokeless gunpowder in our factories. We took the factory preparation of pyroxylin at the Okhtensky powder factories as a sample and changed the details in accordance with laboratory conditions. All laboratory production of pyroxylin can be divided into the following five operations:
1) preparation of cotton (in this case, cotton wool);
2) preparation of an acid mixture (nitrogen and sulfuric);
H) nitration of cotton;
4) washing pyroxylin;
5) drying of pyroxylin;
1) Preparing cotton.
The cotton wool, which is used to prepare loose pyroxylin, is carefully sorted by hand to separate random impurities. It is good to take white absorbent cotton for this purpose.
The cotton wool is dried continuously for 2-3 hours in a drying cabinet at a temperature of about 100°C; When drying, the cotton wool is placed in a thin layer in a porcelain cup or other open vessel. Cool the dried cotton wool in a desiccator over sulfuric acid for an hour.
2) Preparation of the acid mixture.
During drying, you can prepare an acid mixture. We will calculate for 5 g of cotton wool. To obtain insoluble pyroxylin, at the Okhtensky pyroxylin plant they take a mixture containing HNO 3 monohydrate - 21.5% by weight, H 2 SO 4 monohydrate - 70.5% by weight and water 8% by weight; for soluble pyroxylin 18% monohydrate - HNO 3, 68% H 2 SO 4 monohydrate and 14% water. The mixture is taken at the factory in 1 kilogram (when working with a small amount of cotton, you can take less). The density of acids is usually quickly determined using 1) Mohr-Westphal balances or less accurately 2) using a hydrometer.
So for insoluble pyroxylin: A=70.5%; B = 21.5% then if you took 100 g of sulfuric acid containing 95.6% H 2 SO 4 monohydrate or a density of 1.84 g/ml, then using equations (1) and (2) it is calculated that you need to add 35.6 g of nitric acid containing monohydrate 81.8%, which corresponds to a density of 1.463 g/ml; to prepare 1 kg of a mixture of 737 g of sulfuric acid, density 1.84 g/ml, and 263 g of nitric acid, density 1.46 g/ml.
3) Nitration of cotton.
A sample of cotton wool (5 g), cut into as small pieces as possible, is gradually lowered into a glass into which an acid mixture cooled to room temperature is poured, and then mixed with a glass rod. Cotton wool, saturated with the above amount of acids, is then covered with a glass plate and left to stand in the glass: 12 hours - when preparing insoluble pyroxylin and 4 hours when preparing soluble pyroxylin.
4) Washing pyroxylin.
After nitration, pyroxylin is squeezed out of acids as much as possible and after this is washed. First, rinse with cold water for 1/4 hour.
To do this, pyroxylin is moved into a large glass cup or glass and a small stream of cold water is released into the vessel with pyroxylin from the tap using a rubber tube; The water changes all the time, so a siphon adapts to the dishes. During washing, it is recommended to stir the pyroxylin with a glass rod.
After cold washing, the pyroxylin is wrung out and washed with hot water. To do this, in a flask, or better yet, in a tin cylinder, heat water to a boil and steam, using a tube, is carried into a glass or conical flask with pyroxylin, into which such an amount of water is poured in advance so that all the pyroxylin is covered with water.
Hot rinsing is repeated 8 times; 1st, 7th and 8th without any impurities, and during the 2nd, 3rd, 4th, 5th and 6th washings, 0.2 is added to the conical flask where washing is carried out g (calculated for 5 g of pyroxylin) soda. The passage of steam continues for at least one and a half hours at a time; then the water is poured out of the flask, 0.2 g of soda is added if necessary, and steam is passed through again, etc.
5) Drying pyroxylin.
The water is squeezed out as much as possible, using a hand press, the pyroxylin is placed between sheets of filter paper and dried in an oven at a temperature not exceeding 50°C. Pyroxylin must be dried for at least 6-8 hours until it reaches a constant weight. Cooled in a desiccator over sulfuric acid and weighed. The yield of pyroxylin is usually such that from 5 g of cotton wool about 8 g of pyroxylin is obtained.
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Nitro vs polymer
Guitar polish is very often underestimated. It seems like it's just the finishing touch on a guitar, but it's very important and in this article we'll figure out why. The main types of coating are nitrocellulose varnish, polyurethane and polyester. Each of these types has its fans. Varnish protects your guitar from changes in humidity and, in fact, when used correctly, both types of coating perform their functions perfectly.
Nitrocellulose
In order to understand guitar varnishes, let's start with nitrocellulose, we will call it nitro for short. This varnish was first produced in the 20s of the 20th century. Nitrocellulose mixed well with paint, so car companies like Ford quickly adopted this varnish and cars became multi-colored. Previously there were only black and gray ones.
Nitrocellulose is a varnish based on a solvent and resin (mostly cotton), they are mixed with sulfuric and nitric acid and so-called nitration occurs. The same process is used to make nitroglycerin or trinitrotoluene - explosive things, you know. Therefore, nitrocellulose requires very careful handling and is highly flammable. After applying the varnish on the surface of the guitar, the solvent evaporates, and the resin remains on the guitar, it is polished and the guitar acquires that gorgeous shine.
When nitrocellulose first appeared, it was a breakthrough - it dried very quickly, but today polyurethane has overtaken it. When you play a new guitar with a nitrocellulose finish, you can literally smell it. This ends with the evaporation of solvents. It won't last forever, so enjoy the moment. By the way, these chemicals are harmful to nature.
In addition to its pleasant smell and shine, nitrocellulose also has other positive properties - it combines well with other substances and materials. For example, it is used when mixing car paints, the same thing in guitars. Nitrocellulose coating is very easy to restore, unlike polyurethane. This way, if your guitar has any chips or scratches, you can get rid of them quite easily. In fact, nitrocellulose does not dry completely, it is less rigid and does not tighten the wood like other coatings, which is very good for the resonance of your guitar.
Although this is a plus for sound, for reliability it is a minus. Nitrocellulose wears out, for example, when you place the guitar on a rubber-coated stand. You've probably seen guitars with a right-hand mark on the body - where the hand usually rests when playing - this is all because nitrocellulose reacts to fats much more strongly than other harder coatings. Although, many guitarists believe that scars decorate the guitar - this is a sign that you play and practice a lot. Vintage coating with a lot of scratches and chips is especially valued now; many manufacturers even make it artificially. In general, all cracks in varnish are caused by sudden temperature changes, which cause expansion and contraction of wood fibers under the varnish.
In general, this varnish is harmful to the health of those who use it, and to nature in general, so it will most likely be abandoned sooner or later. Interestingly, in the United States, guitars are produced in states with more or less lenient air pollution laws. There you can save on expensive ventilation systems and fines. In general, there is a noticeable transition to polyurethane and polyester simply because it is cheaper for manufacturers.
Polyurethane
This type of coating has been used in guitar manufacturing since the 60s, but has become especially popular in the last 20 years, proving itself both reliable and shiny in appearance. The resin in this varnish is artificial and does not smell anything when the solvents evaporate. Few volatile organic compounds harmful to health. Once applied to the guitar, the varnish hardens and does not react to solvents. When applied to the guitar, this varnish is mixed with hot water, due to which a chemical reaction occurs, the components of the varnish mix and harden without evaporating. Polyurethane coatings are resistant to scratches and wear from friction, and in general, such varnish retains its shine for a long time. If you like your guitar to shine like new no matter how old it is, this type of finish is for you. Unlike guitars with a nitrocellulose finish, which immediately shows their age, guitars with a polyurethane varnish do not age in appearance.
Although polyurethane is generally more expensive than nitrocellulose, it is cheaper to produce because This results in significant savings on ventilation systems. Polyurethane also dries faster than nitrocellulose. This is especially important in mass production, where guitars are boxed straight off the assembly line and sent to stores. Today, large companies use ultraviolet lamps to dry varnish. This takes literally a few seconds. It took years to perfect the process of such artificial drying, but now it takes seconds. A component is mixed into the varnish that reacts to ultraviolet radiation. It causes the necessary reaction. Thanks to this, it was possible to make the coating thinner, which had a better effect on the sound.
A thick coating, regardless of its composition, stifles the sound. No matter how your guitar is coated, the varnish should maintain the resonance of the wood. Nitrocellulose coatings are almost always thinner than polyurethane coatings. Requires fewer layers to finish. Apparently this is why nitrocellulose is still highly valued by professionals. The more layers of varnish on a guitar, the more compressed and constrained the sound, this is especially audible on acoustic guitars, where the entire sound is in the wood. Many electric guitars with a thick layer of varnish and not connected do not sound at all. This, of course, can be heard when you plug such a guitar into an amplifier.
Don't be fooled by the matte finish. In most cases, this type of coating is not thinner than gloss, it simply uses a certain additive in the varnish, due to which it is less shiny. Polyurethane coating, when applied correctly, does not ruin the sound of a guitar, just like proper circuit boards do not ruin the sound of amplifiers. Any coatings affect the sound, and although this can be considered a trifle, for example, a rocker will not notice any noticeable differences, but a jazzman, who cares about natural, clear sound, will.
In general, thanks to the development of technology, coatings are becoming thinner and more reliable. Nitrocellulose remains only in the piece production of expensive guitars, however, its days are already numbered. It costs producers too much.
What type of coverage you choose is up to you. The most important thing is that you like the way your guitar sounds and looks. Remember that your sound is in your fingers.
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SMOKELESS POWDER. Until the 19th century They used saltpeter-gray-coal gunpowder, otherwise called smoky gunpowder, as an explosive. The 19th century was marked by the discovery and invention of a number of new explosives, among them the most important place should be given to pyroxylin, the main substance. Nitrocellulose was first obtained in 1832 by the French chemist Braconneau by the action of strong nitric acid on flax, starch and sawdust. In 1846, Schönbein (Switzerland), by treating cotton with a mixture of nitric and sulfuric acids, obtained nitrocellulose, which had constant chemical properties, which was named due to its explosive properties pyroxylin. In 1872, Volkmann first used an alcohol-ether solvent to process pyroxylin grains from alder wood. In 1884 in France, engineer Viel discovered a method for producing smokeless pyroxylin powder, the ballistic properties of which made it possible to apply it to guns of all calibers and replace all existing black powders in military affairs; he used an alcohol-ether solvent to gelatinize pyroxylin into a plastic mass, from which, by pressing, he obtained powder belts of various thicknesses depending on the purpose of the gunpowder, i.e., the caliber and length of the gun.
The absence of smoke during shooting, although Viel had foreseen, when developing gunpowder he did not set this goal, and the smokelessness of pyroxylin gunpowder was an additional very valuable quality along with other physical and chemical advantages of this gunpowder. Soon in Russia, as well as in Germany, England, Austria and Italy, first pure pyroxylin gunpowder was adopted, and then some states began to use nitroglycerin-pyroxylin gunpowder; the latter was proposed by Alfred Nobel in 1887 under the name ballistite, made from equal parts of soluble pyroxylin and nitroglycerin. In 1889, the English chemist Abel and Professor Dewar proposed another type of nitroglycerin-pyroxylin powder, called cordite, which is made from insoluble pyroxylin, a solvent for it - acetone, nitroglycerin and petroleum jelly; the latter is added to lower the decomposition temperature of gunpowder in order to reduce the heat of the gun channel. In the last 10-20 years, various impurities began to be introduced into the composition of smokeless gunpowder (powder mass): 1) to increase durability, or chemical strength, - diphenylamine and other chemicals, 2) to make the shot flameless - centralite, petroleum jelly, etc. To increase progressive combustion, powder grains from the surface are treated with camphor, dinitrotoluene and centralite, which in powder technology are called phlegmatizers . In Russia, experiments on the production of samples of smokeless gunpowder began at the end of 1887 at the Okhtensky powder plant. By the end of 1889, a completely satisfactory sample of rifle powder was obtained. The material for its manufacture was insoluble pyroxylin, and acetone was taken as a solvent. Since 1890, at this plant, a bulk production of smokeless powder of the lamellar type, adopted in France, was established, for the production of which a mixture of two types of pyroxylin was taken: one - insoluble No. 1, or “A”, with a nitrogen content from 12.91 to 13.29 %, and the other is soluble, No. 2, or "B", with a nitrogen content of 11.91 to 12.29%. An alcohol-ether mixture consisting of 1 part ethyl alcohol and 2 parts sulfuric ether was used as a solvent. Factory-made insoluble pyroxylin No. 1 contains nitrocelluloses soluble in the alcohol-ether mixture from 3 to 7%, and factory-made pyroxylin No. 2 contains them from 94 to 97%. We cannot ignore the research of our scientist D.I. Mendeleev, who in 1890 proposed a special type of nitrocellulose, which he called pyrocollodium, with a nitrogen content of 12.5 to 12.75%. This type of pyroxylin dissolves in an excess of an alcohol-ether mixture (1 part of alcohol and 2 parts of ether), “like sugar in water,” i.e., without swelling, and in the quantities necessary for powder making, it gives a completely gelatinized mass. At one time, the technical advantages of Mendeleev pyroxylin were not recognized by the artillery department as sufficient to replace two types of factory pyroxylin - No. 1 and No. 2, while America established and introduced the production of pyroxylin of the Mendeleev type for the fabrication of smokeless gunpowder. For the navy, smokeless gunpowder was made from pyroxylin of the pyrocollodion type, which met the following basic requirements: nitrogen content 12.92% ±0.05% and solubility in an alcohol-ether mixture 87% ±5%. Thus, pyroxylin smokeless powder is a colloidal substance obtained from pyroxylin by treating it with an alcohol-ether solvent. Thanks to the action of the solvent, pyroxylin is transformed into a dough-like mass, which, using a hydraulic press, is pressed through the holes of the powder matrix and, depending on the shape of the hole, takes the form of a tape, tube or cylinder with several channels. Before the World War, the usual form of gunpowder was either a ribbon of some length or a long hollow tube. As for gunpowder, this form was a 4-angled plate. During the World War, gunpowder, adopted in the United States, came into widespread use, having the form of small cylinders with a known number of holes. Depending on the ballistic requirements of the artillery system, gunpowder is manufactured in different sizes and differs in ch. arr. thickness of the burning layer. Each grade of gunpowder is designated by letters that characterize its purpose.
Properties of pyroxylin smokeless powders:
1) Smokeless powders, due to their colloidal structure, have the ability to burn progressively in the bore of a firearm, in parallel layers, and in this they differ from explosives that decompose almost instantly, i.e., having high explosive properties. The time for complete combustion of gunpowder in the weapon channel and, consequently, the ballistic qualities of gunpowder depend to a large extent on its shape, i.e., on the thickness of the belts, the thickness of the walls of the tubes and the thickness of the “arches” of American-type gunpowder. The width of the belts is determined by the convenience of manufacturing and using gunpowder; The outer diameter of the tubes and grained powders (American type) depends on the thickness of the burning layer and is established by special experiments. The length of belt and tubular gunpowder is set equal to the full length of the chamber or a multiple of it, thereby achieving the possibility of assigning one brand to different guns that differ in chamber length. For American-type powders (with 7 channels), the following size ratios are established: the channel diameter should be equal to 0.5 the thickness of the burning arch, the outer diameter of the grain should be 5.5 times the thickness of the arch, and the length of the grain should be 12 thicknesses of the arch. 2) The color of smokeless powder is dark yellow, turning into brown, reminiscent of the color of wood glue. The greenish-gray, dark gray, or even dark green color that gunpowder is sometimes colored comes from diphenylamine, which is added to the gunpowder to increase chemical resistance. Powders with thinner ribbons, tubes and grains are lighter and more transparent than thicker powders. The transparency and color of gunpowder depend on the processing conditions at various gunpowder factories and do not affect the properties of gunpowder. In small quantities there are ribbons, tubes and grains with a dirty whitish tint; On some tapes and tubes you may notice narrow stripes of a whitish color or small interspersed lumps of ungelled pyroxylin and other random impurities, such as pieces of wood. When looking at the light in some tapes, as well as in tubes, you can notice round or oblong dark spots, which are bubbles of air that were not displaced during pressing. The listed disadvantages in gunpowder in small sizes do not affect its chemical and ballistic qualities. 3) Pyroxylin smokeless powder has the hardness and elasticity of the horny substance, therefore it is almost not subject to grinding into dust - a great advantage compared to black powder. Belts and tubes of gunpowder have significant elasticity and, when bent beyond a certain limit, give a horn-like fracture of a dirty gray color. 4) The finished smokeless powder contains a different percentage of volatile substances: solvent residues not removed from the gunpowder by soaking in water and drying, as well as moisture drawn in by the gunpowder from the atmospheric air. The hygroscopicity of smokeless powder is generally very low; the normal moisture content is considered to be 1.3-1.5%. Under unfavorable storage conditions in humid air, in non-hermetically sealed gunpowder can absorb up to 2.5-3% moisture, which is easily released from it in dry air. An increase in moisture makes the gunpowder burn slower and reduces the initial speed and range of the projectile; a decrease in moisture increases the burning rate and initial velocity of the projectile and increases the pressure of the powder gases in the gun channel, which is highly undesirable in order to avoid dangerous pressures. The amount of volatile substances that must be contained in each type of gunpowder when it is put into service is strictly determined by the standards established for the acceptance of smokeless gunpowder. To avoid changes in volatile substances in the powder, smokeless powder and charges made from it must be stored in a hermetically sealed container. 5) The specific gravity of pyroxylin powder is from 1.550 to 1.630 and depends on the content of volatile substances in the gunpowder. 6) All smokeless powders burn entirely into gases and water vapor. Combustion products of pyroxylin powders: carbon monoxide, carbon dioxide, hydrogen, nitrogen, water vapor and a small amount of methane. The composition of various grades of smokeless powder is expressed by the formula: C 24 H 30 O 10 (NO 3) 10 +kC 3 H 8 O, where C 3 H 8 O corresponds to a solvent that cannot be removed by drying, and k is a variable coefficient; for example, in plates about 2 mm thick k = 0.87. The decomposition of gunpowder at this value of k in a bomb with a loading density (see Ballistics) of about 0.02 is expressed by the equation:
C 24 H 30 O 10 (NO 3) 10 + 0.87 C 3 H 8O =
=5CO2 + 21.41CO + 9.42H2 + 5N2 + 9.06H2O.
If through R designate the amount of residual solvent per 100 parts of dry mass and take into account the values characterizing pyrocollodion, then for different types of pyrocollodion powders the following relationship will be obtained:
These formulas can serve for approximate calculations up to R= 5. The combustion of smokeless gunpowder in the open air occurs calmly, without explosion, and there have been cases of combustion without explosion of even very significant masses of gunpowder, reaching several tens of thousands of kg. Under the action of a highly explosive detonator, smokeless powder explodes and detonates with its entire mass. When subjected to strong friction or impact, smokeless powder will ignite, so sudden movements should be avoided, as heavy charges have been observed to ignite, for example, when moving them along a laboratory bench. Dust from smokeless powder, which is nitrocellulose and has the properties of dry pyroxylin, is especially sensitive to friction and impact. The nature of the combustion of gunpowder changes completely with increasing pressure under which the gunpowder burns - the higher it is, the more energetic the combustion occurs. In the gun channel, in the first moments, combustion occurs slowly, progressively increasing as the pressure of the powder gases increases. The greater the loading density, the higher the gas pressure, and, consequently, the greater the burning rate of the gunpowder. 7) Rifle pyroxylin smokeless powder, designated grade B and adopted for the 3-line rifle of the 1891 model, in the form of rectangular plates 1.7-1.8 mm long, 1.2-1.7 mm wide and 0.36 thick -0.38 mm with a charge of 2.40 g should have given a bullet (stupid) weighing 13.75 g an initial speed of 615 ± 5 m/sec with an average pressure of powder gases of 2500 atm. After pressing and drying, this gunpowder was not subjected to any additional processing and had a yellow color characteristic of pyroxylin gunpowder. In 1908, a new grade of rifle pyroxylin smokeless powder was developed in Russia, designated VL. With a charge of about 3.20 g, it imparted to a pointed bullet weighing 9.5 g an initial speed of 850-865 m/sec with an average pressure of powder gases of no more than 2750 atm.
The gravimetric density for this gunpowder was set at 0.800-0.820, and the weight of the charge could not be greater than the product of the gravimetric density by a factor of 4.0, where 4.0 is the volume of the cartridge case in cm 3. VL gunpowder was made of the plate type with grain sizes: length 1.5-1.8 mm, width 1.2-1.5 mm, thickness 0.31-0.33 mm. To increase the progressiveness of combustion of the powder grain, the gunpowder, after pressing and cutting, was soaked and dried to a minimum content of volatile substances in it, and then treated in special drums with camphor solution and polished with graphite, causing the surface to acquire a shiny black color. Such processing of powder grains in order to slow down the burning rate or reduce the increase in pressure of powder gases (in the first moments) was called “phlegmatization” in factory terminology. Microscopic examination of phlegmatized lamellar powder showed that to satisfy the ballistic instructions, the penetration depth of the camphor solution should be about 5% of the thickness of the powder grain, and fluctuations are permissible within very narrow limits.
In fig. Figure 5 shows VL gunpowder at 4x linear magnification. In the microphotographic photograph of Fig. Figure 1 (made at 35x linear magnification) shows a cross-section of a powder grain prepared for treatment with a phlegmatizer solution. Torn edges characterize unsatisfactory cutting, but this drawback is largely eliminated during subsequent processing - phlegmatization and polishing, because chips and burrs are erased and smoothed out. In fig. 2 and 3 (pictures taken at 35- and 70-fold linear magnification) show a cross-section of phlegmatized VL grain that meets ballistic requirements. In the photo Fig. 4 (obtained at 35x linear magnification) - cross-section of overphlegmatized gunpowder that does not meet ballistic requirements. Powder with an American grain form - a cylinder with one channel - is shown in Fig. 6 (at 7x linear zoom). Grain size: length 2.15 mm, channel diameter 0.17 mm, vault thickness 0.3 mm, gravimetric density 0.900. American VL gunpowder is phlegmatized with dinitrotoluene (travelin), but it can also be phlegmatized with camphor solution. 8) Pyroxylin smokeless powder for revolvers and pistols. quickly burning so that no unburnt grains remain in the short channels of this weapon. Plate type grain size: thickness 0.10mm, square side 1.25mm. 9) Blank smokeless powder. With black powder there were no difficulties in making charges for dry firing. Its burning rate at atmospheric pressure is so high that the blank charge quickly turned into gases and produced a sound similar to the sound of a combat shot. Pyroxylin powder burns very slowly at low pressures, and in order to obtain a loud blank shot with charges of smokeless powder, one has to resort to artificial measures to increase the gas pressure in the first moments after the charge is ignited. The necessary increase in pressure is achieved by using a wad, which replaces the projectile of a combat shot, and by using a very quickly burning type of gunpowder, i.e., thin, for dry firing. Due to the small thickness of the plates and the insignificant content of volatile substances, blank gunpowder loses its chemical resistance more quickly than combat gunpowder, and, consequently, the service life of blank gunpowder is generally shorter than that of combat gunpowder. The serviceability of smokeless blank powder with respect to its chemical resistance is determined by control tests every 2 years. 10) Smokeless powder decomposes under the influence of elevated temperatures: the nitrocellulose from which it is made begins to denitrate with the release of nitrogen oxides. In the initial stages, the decomposition of gunpowder is very slow, and there are no external signs of deterioration. With severe deterioration, light, lemon-yellow spots appear on the gunpowder, sometimes transparent to light, and if you break the powder ribbon or tube at the spot, you can smell the smell of nitrogen oxides. With such signs of decomposition, gunpowder is dangerous for further storage, etc. immediately removed from service. At a temperature of 165°, the decomposition of gunpowder occurs almost instantly and it ignites; at 110°, the chemical resistance of gunpowder decreases significantly after just 50 hours of heating, and then vigorous decomposition begins with the release of brown vapors of nitrogen oxides. At a temperature of about 75°, gunpowder can withstand continuous heating until vigorous decomposition begins for several weeks, and at 40° for many months. At temperatures not higher than 31.2° (25° R) under conditions of official storage in military units and powder storage facilities, the duration of its service until damage is determined by many years (12-25 years). The experience of long-term storage of gunpowder has shown that well-made gunpowder can quickly be spoiled when stored in non-hermetically sealed containers, at elevated temperatures, in damp rooms and when placed in dirty containers. In view of the fact that spoiled gunpowder with a greatly reduced chemical resistance can ignite during storage, all low-resistant gunpowder must be promptly removed from storage, for which constant monitoring of all batches of gunpowder is established, from which samples are taken at certain intervals for chemical tests.
Nitroglycerin smokeless powders are made from a mixture of nitrocellulose with nitroglycerin and come in two types. To the first d.b. gunpowders in which nitrocellulose (pyroxylin) has the property of dissolving in nitroglycerin are classified as ballistite and filite. The second type includes gunpowder in which nitrocellulose (pyroxylin) has a higher nitrogen content, but has incomplete solubility, which is why to obtain good gelatinization it is necessary to introduce an additional solvent (for example, acetone), which is removed during subsequent processing of the gunpowder; these include cordite, solenite and some varieties of German nitroglycerin powders. The production of nitroglycerin-pyroxyline powder mass is carried out by mixing the above components while heating and rolling the mass with hot rollers (50-60°) into sheets that are cut into plates or cubes (ballistite), or the gunpowder is pressed out of a press in the form of strings or tubes (filite, cordite and others). Nitroglycerin powders with good gelatinization are a completely homogeneous elastic mass of light and dark brown color. Ballistites and cordites do not have the hardness of pyroxylin powders and are quite easily cut with a knife. The main advantage of nitroglycerin powders compared to pyroxylin powders is that they have greater strength, i.e., with charges of the same weight, they give high initial velocities. But at the same time, they significantly wear out the bore of the firearm, causing severe burnout of the metal. To increase the service life of guns, it turned out to be necessary to reduce the amount of nitroglycerin and introduce impurities (for example, Vaseline) that lower the decomposition temperature of gunpowder.
Over the last 15 years, Western European countries have developed many other types of nitroglycerin powders with a significantly lower nitroglycerin content, produced using various solvents. Representatives of gunpowders containing nitrohydrocarbon compounds are: “plastomenite”, consisting of 68% nitrocellulose, 13% trinitrotoluene, 6% dinitrotoluene and 13% barium nitrate, and “indyurite”, proposed in America. This type of gunpowder (indyurite) is made from insoluble pyroxylin with a high N content, gelled with nitrobenzene. The mass is rolled between rollers, cut into grains and treated with hot water to remove most of the solvent, after which the gunpowder is dried. Due to the significant technical inconveniences of producing smokeless powders using volatile solvents, several years before the World War, experiments were carried out on the use of non-volatile solid solvents for gelatinization, and the latter were tested: trinitrotoluene, centralites (urea derivatives), orthoni-trophenyl-nitromethane or the dinitrotoluene isomer and etc. The most important task of smokeless powder making is to enhance the chemical strength of smokeless powder. Over time, sometimes determined by tens of years, smokeless gunpowder goes into a state of decomposition, which, under unfavorable conditions, can turn into a violent reaction with such a release of heat that self-ignition of the gunpowder is possible. This circumstance requires very careful monitoring of the manufacturing conditions of both pyroxylin and gunpowder in order to avoid the acceptance of low-quality gunpowder into service and, in addition, the strictest chemical control over its condition. A careless attitude to such an important issue and a lack of proper control lead to disasters such as the loss of the French battleships: in 1907 - “Jena”, and in 1911 - “Liberte”. In order to slow down the processes of decomposition of nitrocellulose and nitroglycerin, various impurities began to be introduced into the composition of smokeless powder soon after its invention, for example: amyl alcohol, urea, its derivatives, castor oil, aniline, petroleum jelly, etc., called “stabilizers”. In 1907-08 The chemist of the Okhtensky powder plant V.A. Yakovlev proposed diphenylamine as a stabilizer, which showed the best results and was accepted in all countries. Introduced into the powder composition in an amount of 0.5-2%, it absorbs nitrogen oxides released during self-decomposition, giving strong nitro derivatives that do not affect the gunpowder. To protect smokeless powders from adverse influences in order to preserve their physicochemical and ballistic qualities, they are stored in hermetically sealed closures, in powder storage facilities that protect against sudden temperature fluctuations, for which, for example, refrigeration machines and ventilation are installed on ships.
