Double-Base Powder

Tensile Strength of Cast Double-Base Powder as a Function of Nitrocellulose Content P 423 Elongation of Cast Double-Base Powder as a Function of Nitrocellulose. Content. .. P 423 Modulus of Elasticity of Cast Double-Base Powder as a Function of 1 1 ... 

Methyl Violet Paper Test for Double-Base Powders , PATR 1652 (1947) 5) S. Helf,... 

The formulation for use in the Swedish Army rifle contained Guncotton 96.2, sol cotton 1.8, resin, a stabilizer and other materials 2.0%. These propints were very stable, nearly hygroscopic, and produced much lower temps than corresponding double-base powders such as Cordite, Ballis-tite, etc. As a result, gun barrel life was lengthened... 

CA 31,5165 (1937) 4)P.Hayard, Vacuum Stability Tests on Solventless Double Base Powders Containing Various Stabilizers OSRD 5959 (20 Nov 1945), 28 Fig 32 5) J.G. Grasselli ed, Atlas of Spectral Data and Physical Constants for Organic Compounds ,... 

Fig 2 Tensile strength of cast double-base powder as function of nitrocellulose content... 

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. 

Crawford, B. L, Huggett, C., and McBrady, J. J., Observations on the Burning of Double-Base Powders, National Defense Research Committee Armor and Ordnance Report, No. A-268 (OSRD No. 3544), April 1944. 

The above estimate at least partly explains why early 12-bore gun cartridges, containing 82 grains (5.3 g) of black powder, could alternatively be loaded with 26 grains (1.7 g) of double-base powder to give similar ballistic performance. 

Germans used cylindrical casings made of double-base powder instead of bags. Such casings burned ust as completely as the propellant... 

Nonpolymerizable, castable, gel-type (cast double base powder) ... 

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). 

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

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

Mechanical properties of double base powders mainly for large rockets will be discussed later (pp. 675 and 678). 

Jolles and Socci [57] also examined the distribution of sodium nitrite in various layers of an Italian tubular double base powder (Polvere C). According to their estimation the distribution of sodium nitrite along the tubes is practically the same whether on the surface or in an internal layer. The distribution varies from the surface to the inside of the tube. In young powders the quantity of nitrite on the surface is higher than inside. With time this may be reversed and in old powders the internal layers may be richer in nitrite. This is shown in the diagram (Fig. 195)... 

VIOLET TEST OF ITALIAN DOUBLE BASE POWDER (POLVERE C)... 

German double base powders are also marked with figures or letters indicating their calorific values. Nitrocellulose powders had no such marks, as their calorific value is approximately the same in all types of powder. 

The German nomenclature for double base powder is given in the appropriate chapter — p. 660. 

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

The manufacture of solventless double base powder began in Japan in 1924. 

It appears that the Japanese Army and Navy used two types of double base powders [33] (Table 186). 

Much attention is now paid to the mechanical properties of smokeless rocket powder [52], This stems from the requirement for physical integrity during manufacture, storage and firing. Any imperfection, such as a crack or deformation or a stress which may lead to a crack in the course of burning can cause serious ballistic malfunction. This defective behaviour is particularly liable to occur in large double base powder grains, hot extruded under pressure. 

Powder casting process. This is the most versatile process for manufacturing double base powder charges of any size and shape. 

Grosse [55] indicated that a typical NG double base powder on static testing should produce a maximum stress of 200 kg/cm2. When the loading rate is increased to 0.23 sec and 0.15 sec until fracture, the stress is 360 and 442 kg/cm2, respectively. 

Pauling, f Changes in the Percentages of Di-phenylamine in Single and Double Base Powders Which Had Been Subjected to Vacuum Stability Tests at 110°, 100°, 90° and 80°C , OSRD 5957 (Nov 1945) 24) A.B. Wester,... 

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

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. 

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