Nitroglycerin powders -> double base

In the German Army nitroglycerine powders (double base powders) possessed the following calorific values 1250, 1150, 950 and 820 kcal/kg. 

Nitroglycerine powder ( double base powder ) is tested at 120°C, the duration of the test being the same. 

Centralite I, II and III are used as -> Stabilizers in gunpowders, especially in nitroglycerine powders (- Double Base Propellants). It is insoluble in water, but soluble in organic solvents. 

The same author [27] gives some data on a propellant which is intermediate between composite and double base propellants. It is composed of ammonium perchlorate and a nitroglycerine-nitrocellulose powder (double base powder). 

Uses In gelatinized form as the basis of all propellants either alone, particularly for cannon powder, or in mixture with guncotton in the small er-caliber guns (See Smokeless Powder), or in mixtnre with nitroglycerine in double-base powders (See),... 

DuPont in the U.S. developed about 1909, a smokeless powder from cotton of relatively low nitrogen that was quite soluble in ether alcohol. A small amount of diphenylamine was used as a stabilizer. After forming the grains and removing the liquid, a coating of graphite was added to make the smokeless powder that was used in the U.S. Other double-base types contain about 25% nitroglycerin. Cotton lint for nitration has been replaced by purified wood cellulose. 

In the simpler version of this method, a double based powder of small size is made by conventional solvent methods and thoroughly dried. The required amount of this powder is then placed in a beaker of cellulose acetate or ethyl cellulose and the voids are all filled with desensitised nitroglycerine. The curing process consists of heating to temperatures of the order of 80°C for a prolonged period and on cooling, the mass becomes a gelatinous body similar to cordite or ballistite. 

Single base" smokeless powder, developed mainly in the United States, uses only nitrocellulose. "Double base" smokeless powder, developed in Europe, is a blend of nitrocellulose and nitroglycerine. "Cordite," a British development, consists of 65% NC, 30% NG, and 5% mineral jelly. The mineral jelly (a hydrocarbon material) functions as a coolant and produces substantial amounts of CO 2, CO, and H 2O gas to improve the propellant characteristics. "Triple base" smokeless powder, containing nitroguanidine as a third component with nitroglycerine and nitrocellulose is also manufactured. 

Double base A smokeless powder that contains both nitroglycerin and nitrocellulose. 

The choice of material for use as inhibitor depends mainly upon the type of propellant, that is, DB, CMDB, Composite and Fuel-rich and also on the ingredients in their formulations. For double-base propellants, cellulosic materials such a cellulose acetate, ethyl cellulose and different filled or unfilled flexible polyesters are used while fuel or binder material filled with inert substances such as asbestos, mica, silica, etc. in fine powder form is used for composite propellants. Since nitroglycerine is present in CMDB propellants also as in DB propellants, the materials used for DB propellants may also be used with minor modifications for the inhibition of CMDB propellants. 

Nitroglycerine or nitrodiglycol powder was known in the U.S.A. as double base powder . 

J. Taylor [27] drew up the following table of the heat of explosive decomposition, the gas volume and rate of burning of British nitroglycerine (double base) and American nitrocellulose (single base) powders (Table 166). 

Double base powders, i.e. nitroglycerine powders without a volatile solvent also include modem flashless powders containing nitroguanidine. 

Transport of liquid nitroglycerine from the nitroglycerine factory to another plant is not allowed in Europe. It can be transported only in mixed forms as dynamites or semi-finished mixtures ready to be used for the manufacture of mining explosives or of double base powders. Only in U.S.A. is the transport of nitroglycerine in special trucks allowed. 

Dinitrodiglycol is as toxic as nitroglycerine. It explodes at a temperature of 200°C developing a relatively small heat of detonation that amounts to 1070 kcal/kg. Advantage is taken of this property in the manufacture of flashless and non-errosive low calorific smokeless ( double base ) powder. 

High explosives may be class d according to their physical properties as powdery, meltable, semi-meltable and plastic. Propellants may be grouped on the basis of chemical composition into gun powder and similar mixtures, nitrocellulose (single base) and nitroglycerine (double base) powders, With respect to their uses and some properties they are divided into black powder, smokeless and flashless powders, and rocket propellants. 

A-E = single base powder A nitrocellulose powder D DNT added F-M = double base powders F = nitrocellulose nitroglycerine G = nitrocellulose-diglycol dinitrate K = ball powder N-P = triple base powders V-W = porous powders (german) TMEMT = trimethylenetrinitrosamine 71... 

Diglycol dinitrate was used extensively in the Second World War by the German side as one of the main components of -> Double Base Propellants. The explosion heat of diglycol in powder form can be kept lower than the heats of the corresponding nitroglycerine powders they represented the first step towards the so-called cold powders. Diglycol dinitrate and triglycol dinitrate are also employed as rocket propellants. 

This term denotes propellants containing two main components nitrocellulose and nitroglycerine or other liquid nitrate esters. Double base powders are important solid rocket propellants. 

The acid-free product is very stable, but exceedingly sensitive to impact. The transportation of nitroglycerine and similar nitrate esters is permitted only in the form of solutions in non-explosive solvents or as mixtures with fine-powdered inert materials containing not more than 5% nitroglycerine. To avoid dangers, internal transport within the factories is made by water injection (- Water-driven Injector Transport). Transport of pure nitroglycerine and similar products outside factory premises is difficult in the U.S., special vessels have been developed in which the oil is bubble-free covered with water without air bubbles which raise the impact sensitivity considerably. The nitroglycerine produced is ideally processed immediately to the products (e.g., explosives double base powders). 

Abel and Deware patented a double-base powder (Cordite) composed of nitrocellulose and nitroglycerine, colloided with acetone. 

Uses Addition of 3-5 per cent camphor to blasting gelatine rednces the sensitiveness to detonation and makes it more resistant to mechanical influences. It is used for the same purpose in double-base powders containing nitroglycerine, where it also acts as a stabilizer. 

Composition Compound propellants containing nitrocellulose and nitroglycerine (15—40 per cent) as principal constituents. Some double-base powders also contain small percentages of potassium or barium nitrate, which salts serve the purpose of reducing flash and rendering the powder more ignitible. 

Composition A double-base powder composed of both soluble and insoluble nitrocellulose, nitroglycerine, and castor oil. 

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