Tetryl secondary explosives

Secondary explosives (also known as high explosives) are different from primary explosives in that they cannot be detonated readily by heat or shock and are generally more powerful. Secondary explosives can be initiated to detonation only by a shock produced by the explosion of a primary explosive. Widely used secondary explosives include trinitrotoluene (TNT), tetryl, picric acid, nitrocellulose, nitroglycerine, nitroguanidine, cyclotrimethylenetrinitramine (RDX), cyclotetramethylenetetranit-... 

The chemical structures of some common mifttary explosives are shown in Figure 1. These include the nitrate esters such as nitrocellulose (NC), NG, EGDN, and (PETN) nitroarenes such as trinitrotoluene (TNT, CH3—C6H2(N02)3), picric acid (HO—C5H2(N02)3), and 2,4,6-trinitrophenylmethylnitramine (tetryl) and nitramines such as RDX (C3H6N6O6), HMX (C4H8N8O8), and hexanitrohexa-azaisowurtzitane (CL— 20). Of these, only CL— 20 is new , that is, less than 50 years old [3]. Mixtures of oxidizers and fuels, such as AN and FO (called ANFO), are also secondary explosives. 

Measurements. Combustion temperatures of PETN, RDX Tetryl were measured at 20-100 atm in a constant-pressure bomb under a N2 atmosphere (Refs 2 3). The absorptivities of the PETN and Hexogen flames were 0.1-0.3 and that of the Tetryl flame 0.8-0.9. In all cases the flame absorptivity increased toward the surface of the charge. If secondary explosives are volatile, as noted by Belyaev... 

Such secondary explosives may be more susceptible than primary expls to combustion instability. Thus, the combustion temperatures for K Picrate and Tetryl at atmospheric pressure are 2800 and 2400°K, respectively, whereas the maximum comb... 

This distinction is more in kind than in degree. Small quantities of primary or initiating explosives usually detonate when exposed to flames or high temperatures whiie secondary explosives usually burn or deflagrate under these conditions. However under slightly altered conditions primary explosives can be made to deflagrate and secondary explosives can be made to detonate. Examples of primary explosives are Lead Azide, Mercury Fulminate, DDNP, etc Examples of secondary explosives are PETN, RDX, HMX, Tetryl, TNT, as single HE compns and Comp B, Comp C, PBX 9404, Dynamite ANFO (Ammonium Nitrate/Fuel Oil) as HE mixtures... 

Figure A. 168 Tetryl secondary high explosive, military explosive main charge.

Examples of secondary explosives are TNT, tetryl, picric acid, nitrocellulose, nitroglycerine, nitroguanidine, RDX, HMX and TATB. Examples of commercial secondary explosives are blasting gelatine, guhr dynamite and 60% gelatine dynamite. 

While Brish et al. directly irradiated the explosive sample with the laser beam, Menichelli and Yang coated a glass window with a 1000 A thick aluminum film. Irradiation of this film generated shockwaves by vaporization of the metal, similar to the functionality of EBWs. [15c, 15d], The generated shockwave is able to directly initiate secondary explosives. In the work of Menichelli and Yang, a Q-switched ruby laser was successfully used (E = 0.8 to 4.0 J r = 25 ns) to initiate PETN, RDX and tetryl. 

Between the extremes lie the more sensitive secondary explosives which are often used in an intermediate role to initiate detonation in less-sensitive substances and are then known as booster explosives. Trinitrophenylmethylnitramine (tetryl) is such a substance, but among all classes of explosives a good deal of "pharmacy" is involved in the formulation of compositions with the desired balance of properties. 

Secondary explosives, which include TNT, cyclo-l,3,5-trimethylene-2,4,6-trinitramine (RDX or cyclonite), High Melting Explosives (HMX), and tetryl, are much more prevalent at military sites than are primary explosives. Since they are formulated to detonate only under specific circumstances, secondary explosives often are used as main charge or boostering explosives. 

MC found primarily at impact areas and tiring lines of U.S. military testing and training ranges often consist of mixtures of residues from several MC. These may include the nitroaromatic explosive compounds 2,4,6-trinitrotoluene (TNT), 2,4- and 2,6-dinitro-toluene (DNT), and trinitrophenylmethylnitramine (tetryl) nitrate esters such as nitrocellulose (NC), pentaerythritol tetranitrate (PETN), and nitroglycerin (NG) and the nitramine compounds, hexahydro-l,3,5-trinitro-l,3,5-triazine (RDX) and octahydro-l,3,5,7-tetranitro-l,3,5,7-tetrazocine (HMX). Most of these MC have been in use for decades, either as primary or secondary explosives or in propellant compositions. 

The dependency of detonation velocity of DDNP on density is summarized in Table 6.2. Its initiating efficiency based on tetryl acceptor charge is better that of MF and LA [12]. The values in TM9-1300-214 [15] confirm superiority of DDNP to MF but the efficiency with respect to LA differs based on the type of acceptor as shown in Table 6.3. It indicates that DDNP is a better initiator for less-sensitive secondary explosives. 

Nitrations of aromatic amines often involve the intermediate formation of N-nitramines, although these are rarely seen under the strongly acidic conditions of mixed acid nitration (Section 4.5). N,2,4,6-Tetranitro-N-methylaniline (tetryl) is an important secondary high explosive usually synthesized from the nitration of N,N-dimethylaniline or 2,4-dinitro-N-methylaniline. ° The synthesis of tetryl is discussed in Section 5.14. 

Secondary high explosive. Main charge in many military munitions Tetryl... 

Examination of nitration acids 167—191 — Examination of finished products propellants, secondary expls and primary expls 192 — Examination of individual expls solid TNT, liquid TNT, Hexogen (RDX), Hexotol (Cyclotol), Hexotonal (RDX/TNT/A1, Torpex), Penthrite (PETN), Bofors Plastic Explosive (BPE), Bonocord, Tetryl, Lead Azide, Lead Styphnate, Mercury Fulminate, Silver Azide and Tetracene]... 

Tetryl is a highly brisant, very powerful explosive, with a satisfactory initiating power which is used in the manufacture of primary and secondary charges for blasting caps. Owing to its relatively high melting point, it is employed pressed rather than cast. 

Fidlar patented a flashlegs propellent explosive formed of nitrocellulose, starch, and dinitrotoluene. Grotta patented compound detonators with a priming charge formed of mercury fulminate, a heavy-metal azide, and a secondary charge formed of a mixture of equal amounts of Tetryl and potassium chlorate. 

Appendix 2 — Secondary High Explosives A2.1 TNT A2.2 Nitrostarch A2.3 Tetryl A2.4 RDX A2.5 Nitroglycerin A2.6 Commercial Dynamite A2.7 Military Dynamite A2.8 Amatol A2.9 PETN A2.10 Blasting Gelatin A2.11 Composition B A2.12 Composition C4 A2.13 Ammonium Nitrate Colophon... 

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