It turned out that no firearm could handle successive guncotton loads without buckling, for guncotton burned far faster than gunpowder, creating ferocious pressures that ruptured breeches, burst barrels, and sheared off rifle grooving. Even manufacturing the guncotton proved dangerous: Several European factories blew up, leaving scores dead. By , production of the miracle material had been almost wholly banned in Europe.
Interest did not fade entirely, however. Producing and weaponizing gunpowder required only stirring together its three basic ingredients—sulfur, charcoal, and saltpeter—in standardized proportions. So straightforward was the process that armies often traveled with barrels of each and simply combined them just before battle. Producing guncotton was a much more complicated affair.
Since its constituent parts were bound organically together, manufacturing it for military use required an expensive laboratory, specialized chemicals, heavy equipment, highly skilled technicians, and at least three weeks of intensive monitoring, purifying, and processing, followed by meticulous refining, grinding, sieving, drying, seasoning, blending, and packing of the nitrated cellulose.
Perfecting the process was a tall order, but laurels and fame awaited the chemist who succeeded. The Austrian general Wilhelm Freiherr Baron von Lenk, a confidant of the Habsburg emperor, maintained a secret, officially sanctioned project to investigate using guncotton as a bursting charge in howitzer shells and was soon testing guncotton cartridges for small arms.
But after analyzing the results, Ordnance evidently concluded that Lenk had been far too optimistic, for that was the last anyone heard of guncotton until , when the department confidently reported that it would remain too unstable for military service use in the future. There were, accordingly, any number of red faces when, just five years later, Paul Vieille, a young French military chemist, unveiled Poudre B—guncotton that had been gelatinized by ether-alcohol and shaped into small slabs for easy cartridge loading.
Soon afterward, a state-owned French manufacturer introduced a new rifle designed specifically to work with Poudre B. Called the Lebel, it was the first smokeless service weapon, and it astounded the world. Within a few years, most had managed to catch up by hook or by crook—mostly crook, as Alfred Nobel, inventor of dynamite, discovered to his chagrin.
Abel soon produced a knockoff called cordite. Nobel, livid at the betrayal, sued unsuccessfully for patent infringement. When in the Russian naval ministry asked Dmitry Mendeleev, inventor of the original periodic table, to develop a smokeless powder, he traveled to France to visit its government explosives experts, only to have every door closed to him for reasons of national security.
Fortunately for Mendeleev, France and Russia were at the time negotiating a military treaty to counter the threat posed by the Triple Alliance of Germany, Austria-Hungary, and Italy.
In the spirit of bilateral friendship, the Russian ambassador prevailed upon the French war minister to allow the scientist to witness a demonstration and take home a two-gram sample of the precious substance.
Unable to procure any guncotton abroad by fair means or foul, the Americans lagged behind their European rivals. In , the Ordnance Department grimly confessed that its every attempt to produce a viable smokeless powder had failed.
In the early s, U. Navy chemist Charles Munroe came close to saving national face by deriving indurite, otherwise known as naval smokeless powder, but it could not be put into production owing to scaling-up problems and other issues. In small arms ammunition, particularly where progressive burning powder is used as the propellant, it often happens that the propellant charge does not completely burn inside the barrel and that combustion thereof is prolonged even after the projectile or shot charge has left the barrel.
This prolonged combustion is objectionable because the burning particles of powder are expelled from the barrel of the arm behind the projectile, and the energy which would otherwise be imparted to the projectile is lost. Spherical smokeless powder is generally made from nitrocellulose as the base material.
The nitrocellulose may be derived from purified cellulose, such as from cotton linters or wood, which is then nitrated by being treated with nitric and sulfuric acids Olsen Olsen F, inventor; Aug In the manufacture of nitrocellulose, it is necessary to subject the nitrated cellulose to extensive purification treatments in order to remove the residual acid and unstable esters from the nitrocellulose fibers. A large amount of water is required for these purification treatments, and a considerable consumption of heat is necessary Olsen Olsen F, inventor; Aug In order to convert nitrocellulose, which has been purified, into gelatinized or colloided smokeless powder grains, it is customary to replace the water contained in the nitrocellulose with alcohol by means of a displacement process Olsen et al.
Nitrocellulose which has deteriorated or contained centers of high acid concentration, as is frequently present in aged cannon powder, may be purified and stabilized to an extent sufficient to for use as propellant.
This may be rendered suitable by grinding the deteriorated nitrocellulose powder in water slurry and thereafter agitating the slurry in a sufficient quantity of a solvent, such as water, to wash out and disperse the centers of high acidity. Regarding the production of the smokeless powder, Olsen and his co-workers developed a process to manufacture a smokeless powder in a manner so as to secure a superior product irrespective within limits of the base.
The base may be nitrocellulose, and its kind and character, as well as composition, may be varied; it may be wholly or partially purified fibrous nitrocellulose; it may be dense colloided nitrocellulose in the form of existing powder, or of good, poor or indifferent stability Silk Silk CE, inventor; May 1.
Smokeless powders process. Also, during the course of operations, the product is purified and stabilized, and the incorporation of additional ingredients, such as stabilizers and modifying agents burning regulators or accelerators , are added Olsen et al. In accordance with Olsen's invention Olsen et al. If the nitrocellulose is impure and in an unstable condition, it is treated with a suitable solvent to form a lacquer from which the impurities are then removed by agitation in a suitable non-solvent bath, such as water.
By distilling off a sufficient amount of the solvent during continued agitation, the gelatinized nitrocellulose becomes converted to preliminary grains.
If the solvent for the powder base is selected so that it will be substantially immiscible with the non-solvent bath, and conditions tending to produce an emulsion with the powder base in the solution as the internal phase are maintained, the preliminary grains may be resolved into globular form and may, if desired, be completely solidified and employed as a propellant powder in this shape, without further operations of grain formation Olsen Olsen F, inventor; Aug To protect the resulting powder against autocatalytic decomposition, one of the usual stabilizers as, for example, the centralities or diphenylamine, may be added to the lacquer so that the desired amount becomes incorporated within the individual particles of lacquer Olsen Olsen F, inventor; Aug The stabilizer is not only uniformly distributed throughout the globules formed within the medium and the grains thereafter formed from globules, but any acidic or deteriorated elements present will be distributed throughout the vehicle or medium Olsen et al.
The modifying agents such as deterrents or accelerators may also be incorporated with a grain and distributed throughout the grain in a manner similar to that of incorporating the stabilizer. In general, the desired formation of the grains is accomplished by dispersing globules of the base such as nitrocellulose in a medium.
This is accomplished by subjecting the base and a solvent to agitation in a non-solvent medium such as water so as to produce globules that are individually consolidated in order to form grains which are spherical Carlucci and Jacobson Carlucci DE, Jacobson SS Ballistics: theory and design of guns and ammunition.
A volatile solvent may also be used to produce globules, being before vaporized by heating Olsen et al. Suitable solvents include ethyl acetate, isopropyl acetate, methyl isobutyl ketone, as well as other organic liquids which are solvents for nitrocellulose not completely miscible with water Coffee Coffee RE; inventor; Jan Particulate nitrocellulose coated with sorbitan trioleate. The treatment with the solvent is preferably carried out to an extent sufficient to convert all of the nitrocellulose present in a lacquer Olsen Olsen F, inventor; Aug The desired amount of solvent may be added to the slurry of nitrocellulose dust in the form of a spray and, in this manner, small globules of the solvent may be readily distributed throughout the mixture.
During agitation and heating, the surfaces of the particles of nitrocellulose dust become softened due to the gelatinizing action of the solvent and tend to coalesce, forming clusters comprising a number of dust particles. This action may be explained since all liquid or plastic two-phase systems tend to a condition of minimum surface energy which can be accomplished by coalescence Olsen et al.
The production of globules or the production of the quasi-emulsion may be secured in various ways. The protective colloid performs the function of effecting a quasiemulsion between the base and solvent and the non-solvent medium, with the base and solvent as the internal phase. The base is agitated with a solvent distributed in the non-solvent vehicle so as to form an emulsion with the medium as the internal phase; upon the addition of the protective colloid the emulsion is broken and under agitation inverted with the medium as the external phase.
The neutralizer is added to remove the highacidity centers. A suitable neutralizer is calcium carbonate in the form of purified prepared chalk Olsen et al. The globules, which are distributed throughout the medium, are then subjected to treatment to extract the solvent, through distillation of the solvent secured by heating the medium to near the vaporizing point of the solvent.
The distillation is so carried out as to effect a gradual vaporization of the solvent from the several globules; the process is preferably carried out by effecting vaporization at a rate decreasing from the beginning to the end of the vaporization period and at a rate less than the rate of diffusion of the solvent from the interiors to the exteriors of the globules.
Such a distillation secures a solid grain as distinguished from one which is hollow and porous Olsen et al. After formation of the globules in the medium or vehicle, and after distillation of the solvent from the several globules to form grains, the medium is permitted to cool to a temperature sufficiently low to permit any modifying agent or stabilizer dissolved in the normally non-solvent medium to separate out at the lower temperature.
In the case of the modifying agent, such as deterrent, it will become deposited on the grains so as to provide a surface treatment in the form of a coating or impregnation Olsen et al. Figure 1 represents a manufacture process of spherical grains of smokeless powders.
Figure 1 Spherical powder manufacturing process. The finishing operations are similar to the ones that are usually carried out during the manufacture of a single-base smokeless powder. After cooling of the medium, and when the grains have become consolidated or hardened, they may be subjected to a screening operation, in which the oversizes can be sent back for reworking and the screened grains can be subjected to a wringing operation and thereafter to a drying operation.
The grains may be surface treated prior to drying with a suitable modifying agent, such as a deterrent or an accelerator. The coating may comprise nitroglycerin which acts as an accelerator; in that it allows the powder to be more readily ignitable and also acts as a waterproofing agent, rendering the powder non-hygroscopic. A suitable deterrent such as dibutylphthalate may be used along with the nitroglycerin or other accelerator and waterproofing agent.
The grains may be then dried and glazed in the usual manner and thereafter blended if desired Olsen et al. The size of the grains is a function of the extent and the violence of the agitation as well as the amount of protective colloid and the viscosity of the dissolved base Olsen et al. The grain size decreases with the increase of rotor speed, the increase of percentage of the colloid and the viscosity of the nitrocellulose.
Furthermore the amount of solvent employed affects not only the size, shape and surface of the resultant grains, but also the gravimetric density thereof Schaefer Schaefer HF, inventor; May Small amounts of solvent give a small rough cluster of particles as the grains while larger amounts of solvent give more spherical smoother grains.
The rate at which the temperature is raised during evaporation of the solvent affects both the granulation and density of the resultant powder Schaefer Schaefer HF, inventor; May The process for the manufacture of spherical powder, which Olsen and his co-workers have devised, combines nicely with Olsen's process for the quick stabilization of nitrocellulose to form a sequence of operations by which a finished powder may be produced more rapidly and more safely than by the usual process.
It supplies a convenient means of making up a powder which contains nonvolatile solvents throughout the mass of the grains or deterrent or accelerant coatings upon their surface Urbanski Urbanski T Chemistry and technology of explosives. Warszawa: Polish Scientific Publishers. Although the spherical powder starts as pure nitrocellulose, the finished product is a double-base propellant, since nitroglycerin is added after shaping and its content is created by surface impregnation.
Table 1 provides a comparison between spherical powders and other common double-base smokeless powders with respect to manufacture process, characteristics and uses.
It aims to briefly compare spherical powders against other double-base propellants. In most cases, it was cut into small strings and packed into a cartridge case like spaghetti. This material was naturally given the name " cordite ". It is also a double-based explosive like ballistite and later, a triple-base cordite was also invented. Abel and Dewar were the target of a lawsuit by Alfred Nobel, who felt that they had merely modified Ballistite slightly.
The case took several years to be resolved and eventually reached the House of Lords, where the court ruled in favor of Abel and Dewar. Disassembled cartridge. Note the light brown strings of cordite which were packed inside it. An interesting feature of cordite and some other smokeless powders as well is that if the strings are burnt outside the cartridge, then they burn rather slowly with a yellow flame and no explosion.
Cordite only explodes if it is lit in a confined space such as a cartridge packed with cordite. It is also very resistant to shock. For example, it is possible to shoot cordite with a rifle bullet and still not explode it. The first version of cordite was labelled Cordite Mk The original version was the cause of early gun barrel erosion and so a new version was invented.
This version did not damage the barrels as much, but exploded with lesser force than Cordite Mk This was made by combining cordite with nitroguanine, which is another explosive. Cordite N was the first triple-base explosive. Despite all the improvements, cordite started to lose popularity around the middle of WW-II when newer propellants were invented. By the end of the 20th century, the last cordite manufacturing plant closed down.
They are made of nitrocellulose, but contain dinitrotoluene DNT to slow down the burn rate of nitrocellulose to a low explosive. Graphite is also added to minimize static electricity and a small amount 0. The powder is extruded out in the form of sticks. Different IMR powders were used to manufacture such famous cartridges as the. IMR powders are still used to this present day and are sometimes known as "stick powder" because the process of extrusion creates sticks of the propellant.
In , another invention was the ball-powder propellant. This is made by dissolving guncotton in ethyl acetate and then forming the round grains under water. This process is similar to how round oil droplets are formed when mixing oil in water and shaking the contents of the bottle. Nitroglycerine is added to the grains to increase the explosive force and dinitrotoluene or a similar substance is added to slow down the burn rate.
Like IMR powders, there are a number of ball powders as well using slightly different proportions and different substances to slow down the burn rate. Ball powders started to gain popularity in the s. The advantages of ball powder over other types of smokeless powder are many. For one, it takes a lot less time to manufacture than other types. Most other smokeless powders take a few months to manufacture. Dupont did manage to get one IMR powder type to be manufactured in 2 weeks.
In contrast, one production lot of ball powder could be made in under two days. Ball powder can also be stored longer than other types. Excess acids during the manufacture of smokeless powder cause the powder to deteriorate more quickly.
The ball powder manufacturing process is more efficient in eliminating most of the excess acid and it doesn't produce much acid as it ages either.
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