Nitrocellulose-nitroglycerine double-base

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). 

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). 

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. 

Propellant residues from discharged single base (nitrocellulose) and double base (nitrocellulose/nitroglycerin) smokeless powders were examined by LC [118]. Five analytes were identified and separated (2,4-dinitrotoluene, -nitrosodiphenylamine... 

Trimethylolethane trinitrate (metriol trinitrate) is not satisfactory as a plasticizer for nitrocellulose, and must be used with other plasticizers such as metriol triacetate. Mixtures with nitroglycerin tend to improve the mechanical properties of double-base cast propellants at high and low temperatures. Metriol trinitrate has also been used in combination with triethylene glycol dinitrate as a plasticizer for nitrocellulose. Its physical properties are Hsted in Table 7 (118-122). 

A third type of propellant, the composite modified-double-base propellant, represents a combination of the other two types. These propellants are made from mixtures of nitroglycerine and nitrocellulose or similar materials, but with crystalline oxidizers such as ammonium perchlorate also included in the matrix. 

The approach taken in the development of an analytical model for the combustion of double-base propellants has been based on the decomposition behavior of the two principal propellant ingredients, nitrocellulose and nitroglycerin. The results of several studies reviewed by Huggett (HI2) and Adams (Al) show that nitrocellulose undergoes exothermic decomposition between 90° and 175°C. In this temperature range, the rate of decomposition follows the simple first-order expression... 

According to Sutton, cast double base charges are likely to contain 45-55% nitrocellulose, 25—40% nitroglycerine, 12-22% plasticiser and 1-2% other ingredients such as stabilisers. Typical properties are ... 

Double base propellant. A propellant based on nitrocellulose and nitroglycerine. 

Double-based propellants are a mixture of nitrocellulose and nitroglycerine. This mixture increases the pressure of the gas inside the gun barrel. Double-base propellants are used in pistols and mortars. Some disadvantages of using double-base propellants is the erosion that this mixture causes to the gun barrel due to higher burn temperatures and the presence of muzzle flash. 

Triple-based propellants are mixtures of nitroguanidine, nitrocellulose, and nitroglycerine. The mixture reduces the muzzle flash observed with double-based propellants, reduces the burn temperature, which protects the gun barrel, and increases the gas volume. Triple-based propellants are used in tank guns, large caliber guns, and some naval weapons. 

M55 rockets pose the greatest storage risk because they contain approximately 20 pounds of M28 propellant, a double-base propellant composed of nitroglycerine, nitrocellulose, plasticizers, a bum-rate modifier, and a stabilizer. The exact composition is given in Table 1-4. The propellant slowly decomposes exother-... 

Since the energy contained within double-base propellants is limited because of the limited energies of nitrocellulose (NC) and nitroglycerin (NG), the addition of ammonium perchlorate or energetic nitramine particles such as HMX and RDX increases the combustion temperature and specific impulse. Extensive experimental studies have been carried out on the combustion characteristics of composite-modified double-base (CMDB) propellants containing AP, RDX or HMX parhclesli- l and several models have been proposed to describe the burning rates of these pro-... 

Nitropolymers composed of -O-NO2 functions and hydrocarbon structures are pyrolants that produce fuel-rich products accompanied by exothermic reaction. Typical nitropolymers are mixtures of nitrocellulose, nitroglycerin, trimethylolethane trinitrate, or triethylene glycol dinitrate, similar to the double-base propellants used in rockets and guns. Mixtures of these nitropolymers are formulated as fuel-rich pyrolants used in ducted rockets. This class of pyrolants is termed NP pyrolants. 

Of these, the most successful appeared in 1887 when Alfred Nobel patented a nitrocellulose propellant plasticised with nitroglycerine. Known as a double-base propellant, it is virtually smokeless, with a very high specific impulse as compared to gunpowder. Single-base propellants were developed in 1865 and 1890 by Schultz and Vieille respectively and these took the form of gelatinised nitrocellulose for use in firearms and mortars. 

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. 

Nitrocellulose does not contain sufficient internal oxygen for complete combustion to CO2, H2O, and N2, while nitroglycerine contains excess oxygen [7]. The double base smokeless propellants therefore achieve a slightly more complete combustion and benefit from the substantial exothermicity of NG (1486 calories/ gram) [7]. 

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

These propellants are also called colloidal or double-base (DB) propellants and have nitrocellulose (NC) and nitroglycerine (NG) as their principal ingredients. Some ingredients may also be added in small proportions to serve as stabilizer, non-explosive plasticizer, coolant, lubricant, opacifier and burning-rate modifier or other additives to impart desirable properties to the propellants. These propellants are processed into desired shapes by two methods, that is, extrusion and casting. They find wide applications in anti-tank missiles. 

In order to raise the Q value of single-base propellants and to increase the pressure of the gas inside the gun barrel, nitrocellulose is mixed with nitroglycerine to form double-base propellants. Double-base propellants have a Q value of about 4500 J g 1 and are used in pistols and mortars. The disadvantage of double-base gun propellants is the excess-... 

Double-base rocket propellant Nitrocellulose (13.25% N content) Nitroglycerine Plasticizer Other additives 2000 2500... 

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