Ballistites

ballistic powders; one of the types of smokeless powder, consisting of cellulose nitrates (usually collodion cotton) and plasticized liquid nitroethers (frequently mixed with other explosive substances). The usual composition of ballistites is 50–60 percent collodion cotton and 25–40 percent nitroglycerin (nitroglycerin powders) or diethylene-glycoldinitrate (diglycol powders) or a mixture of both. In addition, the composition of ballistites includes aromatic nitrocompounds (for example, dinitrotoluene), stabilizers (for example, “centralite”), as well as vaseline, camphor, and other admixtures. Ballistites used as solid rocket fuel frequently contain about 10 percent of powderlike aluminum or magnesium, which increases the heat of combustion; they also contain combustion catalysts (salts or oxides of metals). A comparatively high collodion cotton content is used to achieve the powder grain strength essential for stable, relatively slow burning of ballistites in the bore or rocket chamber.

Ballistites are manufactured by mixing the components of the powder as a suspension in hot water (“cooking” the powder). The water is squeezed out, and the wet powdery mass is passed through hot rollers numerous times. This converts it into powder “cloth” from which, by pressing, extrusion, or calendering, the so-called powder elements are manufactured—that is, plates, ribbons, “vermicelli,” tubes with one or more channels, and so on. The technology of ballistites makes it easy to obtain cylindrical (grain) charges up to 1 m in diameter for rocket engines. Another advantage of ballistites is their high heat of combustion (up to 5–6 megajoules/kg or 1,200–1,400 kilocalories/kg), which is caused by the nitrogylcerin and aluminum or magnesium content. Ballistites are used in firearms (infantry mortars, artillery guns, and others) and as solid rocket fuel. They were introduced by A. Nobel in 1888.