Nitroglycerin Brisance

Nitroglycerine is a very powerful secondary explosive with a high brisance, i.e. shattering effect, and it is one of the most important and frequently-used components for gelatinous commercial explosives. Nitroglycerine also provides a source of high energy in propellant compositions, and in combination with nitrocellulose and stabilizers it is the principal component of explosive powders and solid rocket propellants. 

Naoum 25 reports the results of his own experiments with nitroglycerin and with other explosives in the Trauzl lead block test (sand tamping), 10-gram samples, as shown below. The Trauzl test is essentially a measure of brisance, but for explosives of similar... 

Methyl nitrate is a highly volatile liquid, and its brisance is about equal to that of nitroglycerine. Its vapors are both flammable and explosive and produce headaches. Methyl nitrate dissolves nitrocellulose, yielding a gel, from which it rapidly evaporates. 

Similar mixtures were later used in Germany but with further addition of small amounts of nitroglycerine or collodion cotton, which served to raise the brisance. See Coronite, Percoronite. 

Class IV. Nongelatinous (powdery) Nitroglycerin-Ammonium Nitrate Explosives, known as Ammonium Nitrate Dynamites or Ammonio Dynamites. They contain substantial amounts of AN which usually replaces part of NG and of Na nitrate. The replacement of part of Na nitrate by AN increases die volume of gas produced on detonation. They have approximately die same explosive-strength values as do the Gelatin Dynamites, but have lower rate of detonation and brisance values (Ref 62, p640)... 

Whether it is a -C-NO2, -O-NO2, or -N-NO2 link, all these structural features yield substances that are high explosives. Nitroglycerine, cyclonite, pentaerythrytol tetranitrate, tetryl, trinitrobenzene, trinitro-tolnene, and pentanitroaniline are examples of high explosives. The terms high explosives and low explosives are used for qualitative comparisons only. The explosive power of chemicals or their compositions is determined by their brisance and detonation velocity (see. Part A in Section IV). 

Nitroglycerine in the pure form is a dangerously explosive compound. It detonates when subjected to shock. It explodes when mixed with ozone. Spontaneous detonation occurs when it is heated to approximately 180°C (356°F). It may hydrolyze to glycerol and nitric acid upon exposure to moisture. Such a mixture of nitric acid and glycerol can explode readily. Nitroglycerine detonates with a brisance, which is roughly three times that of an equivalent quantity of gunpowder and proceeds 25 times faster (Meyer... 

Nitrocellulose is a white fibrous solid or amorphous powder. It is wetted with water, alcohol, or other solvent for handling and storage. It may be made to various forms, gel, flake, granular, or powder. Dry material is a low explosive and often used in combination with another explosive, such as nitroglycerine, to obtain more brisance for the composition. Dry nitrocellulose does not detonate but deflagrates. When wetted with water or alcohol, its sensitivity is considerably reduced. 

TNT and picric acid have been replaced gradually by tetryl, RDX, and nitroglycerine (Section 9-11). On the research front, chemists are continuing to explore novel structures. A case in point is octanitrocubane, synthesized in 2000, in which ring strain adds to the brisance of the compound. Its molecular formula, CgNgOig, indicates the potential to generate 8 CO2 -f 4 N2 molecules, with an associated 1150-fold volume expansion. A recent example from 2012 is the exotic salt TKX-50, in which two lone carbon atoms are surrounded by 10 nitrogens and the equivalent of 4 H2O moieties. 

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