Colloided smokeless powder

L. A. Burrows G. A. Noddin, 36, 2725 (1942) Ignition composition suitable for blasting explosives comprised of finely divided colloided smokeless powder mixed with 15-25% of the Pb salt of a dinitrophenol such as 4,6-dinitro-cresol-[CH3. C6H2(N02)2O] 2 Pb USP 2268372 (1941)... 

Figure 71. Sweetie Barrel. (Courtesy Western Cartridge Company.) The moist and mixed ingredients of bulk powder, tumbled in this apparatus, take on the form of grains. Similar equipment is used for sugar-coating pills and for applying a deterrent coating or a graphite glaze to grains of colloided smokeless powder.

Schuitze s Explosives and Powders. Schultze, an artillery captain in the Ger army, in 1867 patented a series of propints based on Nitro-lignin (nitrated woodmeal or sawdust). The smokeless powders antedated by at least 20 years colloidal smokeless powders developed independently by P. Vieille in Fr and M. Dutton-hoffer. Two examples of Schuitze s powders are given by Daniel (Ref, p 707) as follows ... 

M. von Duttenhofer (1843-1903) nitrated brown charcoal (used for prepn of C/82) by Schultze s method to obtain colloided rifle powder RCP (Rottweiler Cellulose Pulver) which was adopted by the German Army in 1884, but its compn was kept secret until 1887 (See also Vol 5 of Encycl, p D1581, under Duttenhofer s Smokeless Propellant ) (Ref 44, p 244)... 

Soon after the manufacture of nitrocellulose smokeless powder began it was established that the powder obtained by the partial dissolution of nitrocellulose in a mixture of alcohol and ether (partly colloidal powder) has a chemical stability inferior to that of the nitrocellulose from which it derived. Thus Vieille [11] reports that on heating to a temperature of 110°C CPj guncotton undergoes denitration with the evolution of 0.04 cm3 NO/hr/gramme whereas the powder obtained from these substances without a stabilizer undergoes denitration at more than twice the rate, namely 0.10-0.15 cm3 NO/hr/gramme of substance. 

After World War I the influence of sea water on the stability of smokeless powder was examined. It was found that nitrocellulose powder submerged in the sea during military activities did not suffer any perceptible deterioration as a result of immersion in sea water for several years, neither in its colloidal properties nor in its stability. 

Nitroglycerine powders can be classified into two groups with and without a volatile solvent. Semi-colloidal nitrocellulose powders and nitroglycerine solventless powders are the most important types of smokeless powder. 

Smokeless powders containing nitroglycerine are classified into two types those produced with the use of a volatile solvent and those produced without such a solvent. In both types nitrocellulose is in a completely colloidal form. 

Esters and ethers of cellulose, and especially nitrocellulose, are most widely used in the form of a colloidal solution. This technique is applied in the manufacture of smokeless powder, nitrocellulose varnishes, film and celluloid. 

Accdg to Ref 4, Cannonite was a smokeless propint manufd in the 1890 s by the War and Sporting Smokeless Powder Syndicate, Ltd. It consisted of NC(mostly insol in eth-alc) 86%, some Ba nitrate and small quantities of K nitrate, charcoal, lampblack, vaseline, rosin, stearine, DNB, TNT, K ferrocyanide graphite. For rifles the propint was fully colloided. The compn given in Ref 5 is nitrocotton 86, Ba nitrate 6, K ferrocyanide 2, lampblack 1 vaselin 3%... 

An account of smokeless powder is, in its main outlines, an account of the various means which have been used to regulate the temperature and the rate of the burning of nitrocellulose. After the degree of nitration of the nitrocellulose, other factors which influence the character of the powder are the state of aggregation of the nitrocellulose, whether colloided or in shreds, the size and shape of the powder grains, and the nature of the materials other than nitrocellulose which enter into its composition. 

Figure 73. Smokeless Powder Manufacture. (Courtesy E. I. du Pont de Nemours and Company, Inc.) Dehydrating Press. The nitrocellulose comes from the dehydrating press in the form of a cylindrical block, impregnated with alcohol, ready for the mixer where ether is added and where it is colloided.

Calcium carbonate, either powdered limestone or precipitated chalk, is used as an anti-acid in dynamite where it serves as a satisfactory stabilizer. Urea is used in dynamite and in celluloid. It reacts with nitrous acid to produce nitrogen and carbon dioxide, and is unsuitable for use in smokeless powder because the gas bubbles destroy the homogeneity of the colloid and affect the rate of burning. The small gas bubbles however commend it for use in celluloid, for they produce an appearance of whiteness and counteract the yellowing of age. 

Uses In uncolloided form as flame carrier in central tube of shrapnel shell to connect the fuze with the base charge of black powder. Formerly the principal charge for torpedo war heads and sea mines, now being replaced by TNT. In colloided form in the manufacture of high-grade smokeless powder, in mixture with pyro-cotton (See). 

Composition A smokeless powder, formerly used in the U. S., consisting of 40 per cent guncotton, colloided with 60 per cent nitrohenzene,... 

In 1886, Vieille placed the art of smokeless-powder manufacture on a real foundation by producing the first thoroughly colloided nitrocellulose powder in the form of square flakes of uniform size and thickness. 

Properties White, pulped fibers. 12.6 per cent nitrogen. Soluble in ether-alcohol (2 1) and in acetone. Less corrosive on bore of gun than guncotton. For conversion to smokeless powder it is colloided with volatile solvents with or without addition of some non-volatile solvents. 

---