Heat-resistant Explosives

This low viscosity resin permits cure at low (70°C) temperatures and rapidly develops excellent elevated temperature properties. Used to increase heat resistance and cure speed of bisphenol A epoxy resins, it has utihty in such diverse appHcations as adhesives, tooling compounds, and laminating systems. A moleculady distilled version is used as a binder for soHd propellants (see Explosives and propellants) and for military flares (see Pyrotechnics). Its chief uses depend on properties of low viscosity and low temperature reactivity, particularly with carboxy-terminated mbbers. 

NONA combines exceptional heat stability with a very low vap press, making it attractive as a booster expl in space applications Refs 1) J.C. Dacons, Heat Resistant Explosives VIII 2,2,4,4,6,6 -Hexanitrobiphenyl (HNB) ... 

I. Heat Resistant Explosives (U), NOLTR 65-220 (1966) ( Contents Confid-material not used in above article)... 

Heat Resistant, Castable Explosive For Fragmentation Type Warheads , NOTS TP 3612, NAVWEPS 8597 (1964) 39) H.L. Herman,... 

Heat Resistant Explosive Compositions Capable of Withstanding 500°F and Higher , NWC TP-4461 (1967) 44) Ibid, Castable Explosive... 

Dies In Isostatic Pressing , NWC TP4881 (1973) 65) H. Heller A. Bertram, HNS/Teflon, A New Heat Resistant Explosive , NOLTR 73-163 (1973) 66) M.E. Sitzman et al, Solubilities... 

TATB or 1,3,5-triamino-2,4,6-trinitrobenzene (C6H6N6Oe) is a yellow-brown crystalline solid that has excellent thermal stability and is known as a heat-resistant explosive. TATB has a decomposition point of 325°C. Its molecular arrangement provides lubricating and elastic properties. 

Hexanitrostilbene or HNS (C14H6N6012) is a heat-resistant yellow crystalline solid explosive. HNS is also resistant to radiation, insensitive to electric sparks, and less sensitive to impact than tetryl. It is used in heat-resistant booster explosives and has been used in stage separations in space rockets and for seismic experiments on the moon. Its melting temperature is 316 °C.12... 

A,A -Bis(3-aminopicryl)-l,2-ethanediamine (108) (m.p. 275 °C) is prepared from the reaction of ethylenediamine with two equivalents of 3-chloro-2,4,6-trinitroaniline. " The same chemists reported 3,3 -diamino-2,2 4,4, 6,6 -hexanitrodiphenylamine (109), a heat resistant explosive (m.p. 232-237 °C) prepared from the reaction of l,3-dichloro-4,6-dinitrobenzene with 3-chloroaniline followed by mixed acid nitration and subsequent chloro group displacement with ammonia. The potassium salt of 3,3 -diamino-2,2, 4,4, 6,6 -hexanitrodiphenylamine shows very high thermal stability. " ... 

Trinitrobenzyl chloride is isolated in 85 % yield if a reaction mixture composed of TNT and 5 % aqueous sodium hypochlorite in methanol at 0 °C is quenched into dilute acid after 1 minute longer reaction times at ambient temperature lead to the isolation of the heat resistant explosive 2,2, 4,4, 6,6 -hexanitrostilbene (HNS) in 42 % yield. HNS (16) is also formed in 50 % yield from the reaction of 2,4,6-trinitrobenzyl chloride (145) with sodium hydroxide in THF-methanol. Sollot ° later found that the yield of 2,2, 4,4, 6,6 -hexanitrostilbene (16) could be increased to 70 % by treating the same substrate with 2.4 mole equivalents of triethylamine in the same solvent mixture. 

Naval Ordnance Laboracoty, "Heat Resistant Explosives XV , NOLTR 62-175 (1962)... 

C-L. Scott, The Sensitivity of Selected Conventional and Heat Resistant Explosives at Low Temperatures", NOLTR 70—36 (1970), reviewed by G. Cohn, Edit in Expls- Pyrots 4(6), 1971 (The effects of temp, confinement, and column diam on the shock... 

Explosives with improved high-temperature properties are usually termed heat-resistant or thermally stable explosives [23-25]. Some specific applications of explosives for drilling deep oil-wells, space exploration etc., demand heat-... 

For this purpose, nitro compounds have received special attention because of their ability to withstand high temperatures and low pressures encountered in space environments. The research on heat-resistant explosives was reviewed first by Dunstan [26] followed by Urbanski and Vasudeva [27], Lu [28], recently by Agrawal [29, 30] and Sikder [31]. 

Octahydro-l,3,5,7-tetranitro-l,3,5,7-tetrazocine or cyclotetramethylene tetranit-ramine (HMX) with a m.p. of 291 °C, is also regarded as a heat-resistant explosive in some countries [32, 33] and its safe working limit is 225 °C. 

Introduction of Conjugation The best example of imparting higher thermal stability through the introduction of conjugation in explosive molecules is hexanitrostilbene (HNS), synthesized by Shipp [58, 59] of the US Naval Ordnance Laboratory (NOL) in 1964. Plants for full-scale production exist in the UK and China, based on the method of Shipp [60]. It has proved its efficiency as a heat-resistant explosive as well as a component of heat-resistant formulations employed in the Apollo spaceship and for seismic experiments on the moon [61]. HNS has also been reported for use in achieving stage separation in space rockets. 

In addition to these heat-resistant explosives, there are some well-known thermally stable explosives which have some additional features and are described in... 

Triamino- 2.4.6- trinitro benzene (TATB) >350 1.94 Very insensitive 8000 Explosive with unusual insensitivity, heat resistance and respectable performance. Used for space, nuclear and special military applications (high speed guided missiles)... 

It is, in fact, a combination of properties such as compatibility, tensile strength (TS), % elongation (E), bond strength (BS) with propellant and explosive plasticizer (NG)/non-explosive plasticizer (TA,DEP,DOA,DOP etc.) migration or absorption, heat resistance and flame retardance which makes a polymer suitable for inhibition of solid propellants. A compromise among these properties is made in such a way that the performance of inhibited propellants after conditioning at ambient, cold (-40 °C) and hot (+60 °C) temperatures is satisfactory during static evaluation. 

Refs 1)M.F. Murphy N.L. Coleburn, A Preliminary Evaluation of TACOT, a New Heat Resistant Explosive NOLTR 61-155(Nov 1961) (Conf, not used as a source of info)... 

Heat Resistant Explosives XVr — A New Synthesis of 2,2,414l,6,6l-Hexanitrostilbene, HNS , NOLTR 64-34(1964) (Conf, not used as a source of info) 7) Navy Dept, Bureau of Weapons, NOL, Md, Purchase Description, HNS Explosive WS 5003C St D (June 1965) (Unclassified) 8) Del Mar Engineering Laboratories, Los Angeles, Calif (no date)... 

It is a yellow-brown coloured substance which decomposes rapidly just below its melting temperature. It has excellent thermal stability in the range 260-290 °C and is known as a heat-resistant explosive. Some of the properties of TATB are given in Table 2.17. 

HNS [hexanitrostilbene (C14H6N6012)] (2.17) is known as a heat-resistant explosive and is also resistant to radiation. It is practically insensitive to an electric spark and is less sensitive to impact than tetryl. Some of the properties of HNS are shown in Table 2.18. 

HNS is used in heat-resistant booster explosives and has been used in the stage separation in space rockets and for seismic experiments on the moon. 

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