Military explosive

Military explosives are required to meet stringent criteria because apart from a requirement for high performance, the military needs to be able to safely store them for decades, transport them anywhere from the poles to the equator, handle them under battlefield conditions, and still have them fuUy functional. In addition, availability of raw materials, ease of manufacture, and cost are important factors. Most candidate explosive compounds do not meet all these requirements. 

Ranking related to blast pressure of TNT is termed TNT equivalence . This value cannot be uniquely defined because in a single shot the TNT equivalence 

The explosives used for military purposes are different from those used in industry. Not only thermo mechanical power for destruction, but also various other characteristics are required. Experimental tests, such as slow cook-off fast cook-off, bullet impact, and sympathetic explosion tests, must be passed to meet the requirements for insensitive munitions (IM). The aerodynamic heating of warheads on flight projectiles is also an important factor in designing warheads. 

Mixtures of TNT, RDX, and/or AN are used as TNT based explosives. Various additives such as aluminum powders, barium nitrate, and/or some other small amounts of materials are used. The density is in the range 1450 kg/m3 - 1810 kg/m3. Aluminum powders are added to give bubble energy when used under water conditions. 

There are various types of crystalline materials and polymers used to formulate PBX. Table 4-20 shows typical materials used for PBX. Though the polymers used are not the same as those used for propellants, the fundamental concept of the selection of the materials for PBX is the same as that for propellants as shown in Table 4-20. 

Energetic materials (oxidizer) Polymeric materials (binder and fuel)  

AN Nylon, Viton, Polyester-styrene, HTPB, Polyurethane, Silicone resin Fluoronitropolymer, TEGDN A1 

2 Samer, S. F., Propellant Chemistry, Reinhold Publishing Corporation, New York (1966). 

Blackpowder mills (using the Corning process) were erected at Rotherhithe and Waltham Abbey in England between 1554 and 1603. 

The Nobel family suffered many set backs in marketing nitroglycerine because it was prone to accidental initiation, and its initiation in bore holes by blackpowder was unreliable. There were many accidental explosions, one of which destroyed the Nobel factory in 1864 and killed Alfred s brother, Emil. Alfred Nobel in 1864 invented the metal blasting cap detonator which greatly improved the initiation of blackpowder. The detonator contained mercury fulminate [Hg(CNO)2] and was able to replace blackpowder for the initiation of nitroglycerine in bore holes. 

The mercury fulminate blasting cap produced an initial shock which was transferred to a separate container of nitroglycerine via a fuse, initiating the nitroglycerine. 

After another major explosion in 1866 which completely demolished the nitroglycerine factory, Alfred turned his attentions into the safety problems of transporting nitroglycerine. To reduce the sensitivity of nitroglycerine Alfred mixed it with an absorbent clay, Kieselguhr . This mixture became known as ghur dynamite and was patented in 1867. 

Nitroglycerine (1.1) has a great advantage over blackpowder since it contains both fuel and oxidizer elements in the same molecule. This gives the most intimate contact for both components. 

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B. C. Pol and M. B. Ryan, Database Assessment of Pollution Control in the Military Explosives and Propellant Production Industry final report ORNL-22, Oak Ridge National Lab., Term., Feb. 1986. 

The Dow Chemical Company started production of chlorobenzenes in 1915 (3). Chlorobenzene was the first and remained the dominant commercial product for over 50 years with large quantities being used during World War I to produce the military explosive picric acid [88-89-1]. 

Require that explosives shall not be transported unless they have been classified by the classifying authority (i.e. the HSE, and the MOD for military explosives, in the UK) (except for journeys made specifically for classification and then only under certain conditions). 

Microanalysis of Explosives. See under Color Reactions and Color Reagents in Vol 3, C405-L to C420-L, and Addnl Refs below Addnl Refs 1) Anon, Military Explosives ,... 

Addnt Ref A.J. Phillips, Suitability of NENO as a Military Explosive , PATR 1441 (1944)... 

Nobel s 704. See under British Military Explosives and Propellants in Vol 2, B301-R... 

Anon, Regulations Governing Transportation of Military Explosives on Board Vessels During Present Emergency , NAVCG 108, Wash, DC (1945) 3) Anon, Explosives or Other Dan-... 

It should be noted that the incorporation of substances such as TNT increased the sensitivity to initiation, and the addition of AN increased the quantity of expln gases, while at the same time diminishing the sensitivity of the perchlorate expl to open flame Refs See below under Inorganic Perchlorate Military Explosives... 

Ref K.G. Ottoson, Development of Military Explosives Equivalent to Commercial Dynamites , PATR 1760 (1950)... 

POLLUTION abatement IN THE US MILITARY EXPLOSIVES AND PROPELLANTS MANUFACTURING INDUSTRY... 

Expl Power is always measured in relative terms, ie, relative to a standard expl and expressed as a percentage. For military explosives the consensus standard is TNT, and for commercial expls the standard is usually Blasting Gelatin (see Vol 2, B211-R). Three measurement methods are in common use ... 

Experience has shown that the oxygen distribution in the products of a metallized military explosive favors the formation of the metal oxide. Any remaining oxygen then forms steam with the H of the expl. If any oxygen is still available it forms C02, and any unreacted C atoms then show up as free carbon in the products. (Confinement of the expls favors the formation of C02 and C at the expense of CO). In halogenated expls HX appears to be formed in preference to H20 and H2... 

N.E.C. is the major manufacturer with a complete range of explosives and accessories, with factories in Scotland, Wales and England. Explosives and Chemical Products Ltd., with factories in England, is the other manufacturer of explosives for sale. The major commercial manufacturer of ammunition is Imperial Metal Industries (Kynoch) Ltd. at Witton near Birmingham. The British Government has of course a number of Royal Ordnance Factories and establishments to cover all aspects of military explosives. 

Explosives of all types are made for commercial and military purposes in many countries throughout the world. It is, however, difficult to obtain any figures which give a worthwhile idea of the magnitude of the explosives industry. Military explosives are usually made under conditions of secrecy and no figures of output are published. Even for commercial explosives published figures are scanty and vary considerably from country to country. Data which are available are given in Table 1.1. 

From the days of Nobel to about 1950 the scientific basis of commercial explosives remained relatively unchanged, although continuous and numerous improvements in manufacturing methods occurred throughout the world. There were, however, many advances in military explosives, note of which will be made later. These advances were, of course, largely due to the two world wars, which occurred since the death of Alfred Nobel. There were also many advances in the development of permitted explosives designed for use in gassy coal mines. 

Tables 2.1 and 2.2 show that theory enables detonation velocities to be calculated in close agreement with those observed experimentally. This, unfortunately, is not a critical test of the theory as velocities when calculated are rather insensitive to the nature of the equation of state used. A better test would be to calculate the peak pressures, densities and temperatures encountered in detonation, and compare these with experimental results. The major difficulties here are experimental. Attempts to measure temperatures in the detonation zone have not been very successful, but better results have been obtained in the measurement of densities and pressures. Schall introduced density measurement by very short X-ray flash radiography and showed that TNT at an initial density of 1 -50 increased 22% in density in the detonation wave. More recently detonation pressures have been measured by Duff and Houston using a method (introduced by Goranson) in which the pressure is deduced from the velocity imparted to a metal plate placed at the end of the column of explosive. Using this method, for example, Deal obtains the detonation pressures for some military explosives recorded in Table 2.3. More...

In this chapter the explosives employed are discussed their actual application is described in Part III. The most important properties of the commonest military explosives are listed in Table 3.1. 

For PETN and similar military explosives a valuable test is a vacuum stability test, in which some of the explosive is heated in vacuum and the rate of evolution of gas measured. 

The quantity of military explosives made in the Second World War exceeded the total ever made for peaceful use by mankind. On this count it could be argued that military explosives should occupy a major portion of this book. On the other hand, wars are fortunately relatively shorter in duration than peace, so that at any particular time a reader is likely to be interested more in commercial explosives than in military. 

Ethylenediamine dinitrate was formerly used as a military explosive. 

Some studies relating to the explosion mechanism of this military explosive (RDX... 

The military explosives RDX and HMX are manufactured from the 3 components using the Bachman process. Some of the possible mixtures may lead to fires in open vessels and explosions under confinement, and the exothermic and other effects (some calculated by the CHETAH program) for a wide range of mixtures are presented as ternary diagrams. It was also found that acetic anhydride layered onto solutions of ammonium nitrate in nitric acid exploded, owing to formation of acetyl nitrate. 

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