High expls, detonics

When a high expl detonates the effects may be divided into several phases (Ref 2) a)The phase in which the expanding gases cause the case to swell and fragment is called the Frag ... 

In general terms, PETN can be characterized as a sensitive , brisant, and powerful high expl. Explosive sensitivity is a rather nebulous quantity, but there can be no doubt that PETN is a much more sensitive material than TNT, but rather less sensitive than Lead Azide. In particular, PETN requires very little priming i charge (less than 1 mg LA) to initiate its detonation. This is the characteristic that makes PETN so widely used in blasting cap base charges, in detonating cord and in boosters... 

As shown in Fig 4, the stab detonator is a small, sensitive component which is capable of reliably initiating high-order detonation in the next HE element in the expl train. It differs from the primer in that its output will initiate reliably secondary HE charges... 

The selection of a stab detonator for a specific application requires a consideration of both input and output (Ref 7). The situation exactly duplicates the problems encountered in the selection of a percussion primer. However, as previously discussed, the end purpose of a detonator is different the input energies are significantly lower, and the output is intended to initiate a high expl. In addition to the main criteria, consideration must also be given to size, weight, cost, and reliability... 

Some unconfined high expls can also be ignited to deflagration especially if they are in a molten condition (such as TNT), or spread in a thin layer (such as MF or Diazodinitrophenol). In many cases deflagration develops into detonation [See also Detonation (and Explosion), Initiation of] Refs 1) F.P. Bowden, "The Initiation of Explosion and Its Growth to Detonation , PrRoySoc 204A, 20 ff (1950) la) A.F. Belyaev, ZhPraktKhim 23, 432 ff (1950). 

Cook (Ref 15) also reported that the shock transmitted thru a barrier into a transparent liq expl, appeared (from the partial opacity of the liq behind the shock front) to initiate some reaction at once. The high-velocity deton appeared, on the other hand, to start as a much more intense luminosity at one or more centers randomly distributed within the reacting liq. Often an intense flame is observed to flash across the region just traversed by the shock wave, at a velocity far above the normal deton vel, and upon reaching the shock front to start a high-order deton (See also Ref 17, p 13b)... 

Dr Donna Price stated (Ref 14, p 698) that in her Group 1" (which includes most organic high expls such as RDX,PETN and TNT) the homogeneous processes rather than the heterogeneous ones (such as noted by Eyring) play the major part in the transmission, if not the initiation, of detonation (Ref 23)... 

The case with which highly expl Xe03 may be formed at room temp by reaction of Xe fluorides with moisture has been strongly emphasized (Refs 2, 3 4). Xenon trioxide, Xe03, is a wh sol comparable in deton sensitivity to nitrogen triiodide and in expl force to TNT Refs 1) N. Bartlett P.R. Rao, Science 139, 506 (1963) 2) D.F. Smith, JACS 85, 816... 

A laser-initiated pyrotechnic system (Zr-Amm perchlorate) for spacecraft application has been shown to be superior to conventional electroexpl initiation (Ref 22). Primary high expls such as LA and LSt can be initiated directly. Q-switched-mode lasers can directly deton PETN, RDX, and Tetryl in a properly designed device and can be useful where microsecond simultaneity is important (Ref 6)... 

Low Order Burst. Functioning of a proj or bomb in which the expl fails to attain a high order deton. Usually evidenced by the breaking of the container into a few large fragments instead of a large number of smaller fragments Ref OrdTechTerm (1962), 181-R... 

Sensitivity to Initiation by Primary Explosives, Detonators and Boosters. It can be expressed as the minumum weight of an initiating expl or the No of detonators to cause a complete detonation of a HE (high expl). See Voll,... 

Further improvements were made to follow continuously the initiation growth of high velocity detonation, low velocity deton, and low vel reaction. Shock sensitivity scales were established in Al, Plexiglas polyethylene container. Also s-zveral other casting solvents were compared with the above liq expls... 

Accdg to Nieuwland et ai (Ref 2), DVA rapidly absorbs oxygen from the air, forming a highly expl peroxide (ozonide) which has been found to detonate spontaneously with... 

Hexanitroazobenzene is a very powerful and brisant high expl. Its Power as measured by the Trauzl test is 113% PA or 123% TNT and its Impact Sensitivity is between that of tetryl and PA the FI value is 617t> PA. According to Davis (Kef 3) this expl is suitable for boosters and compound detonators. Tke presence of the a o group in hexanitro azobenzene makes it more powerful and brisant than hexanitrodipbenylamine (qv)... 

Detonation velocity (also called detonation rate) is the speed at which detonation progresses thru an expl- Commonly it is designated by the symbol D, and it is usually understood to be a steady velocity, and not a transient velocity such as that observed in build-up to detonation or in overdriven detonations. The contents of this article are limited to steady high-velocity detonations. Detonation velocity is the most easily and most accurately measurable detonation parameter (other detonation parameters are detonation pressure, particle velocity, temp, etc). Consequently there exists a large body of exptl and theoretical literature on this subject. Much of this literature, up to about 1965, was summarized in Vol 4, pp D223-224,232-235, 242-245,280,352,356,362,384-389,460-461, 463-464, 629-637, 641-652, 657-660, 663—675 and 718—721. The present article is a selected review of published information on detonation velocity from 1967 to date... 

Proplnts (single and double base) are designed and used in applications where ignition results only in controlled burning. However, since these materials are basically high expls (Nitrocellulose, Glycerol Trinitrate), under specific conditions, they do detonate... 

Fig 2 shows a typical smear camera wedge record. Characteristically, these traces show the initial shock, the point of transition to high-order detonation, and the high-order detonation. The space and time dimensions are shown. Although the shock and detonation velocities in the expl can be determined from these records, only the coordinates for the high-order detonation, x and t, are normally found. Historically, many analysis techniques have been used, including those used here for data analysis . 

According to Davis(Ref 3) this compd is a brisant high expl suitable for use in boosters, detonators, detonating fuses, primer caps, etc. It requires 0.19 g of MF to detonate a 0.4-g sample in the Sand Test and is si more brisant than TNT. In the drop test, it is about the same in sensitivity to impact as Tetryl Refs l)Beil 12,768,(370) [4233 2)R.I.C. 

Blasting Squibs, Electric. Elec squibs are devices useful in igniting deflagrating expls(such as BkPdr), where the nature of the expl is such that it is desirable to fire the chge by means of a flame, as distinguished from dynamites and other high expls, which are initiated by the deton of expls contained in ordinary elec caps(see under Blasting Initiators)... 

Jones Sheffield(Ref 5) also discussed the relationship between brisance(as detd by the Sand Test) and deton velocity but their data cannot be included here because it is classified Refs I)H.Kast A.Haid,ZAngewChem 38,50-2 (1925) (Brief discussion on relationship betw brisance and detonation velocity for initiating expls cyanuric triazide, LA, LSt, MF and 90/10-MF/KC103) 2)T.Urbanski,SS 30,68-71(1935) CA 29,4941(1935) [For expls such as TNT or AN expls, detonation velocity may be calcd from the equation D = (24.9Sp)2 where D is detonation velocity, Sp is compression of Cu cylinder in mm minus correction 0.16mm (Compression produced by a No 8 cap)i This relationship does not hold for some chlorate expls] 3)W.H. Rinkenbach, Study Fundamental Properties of High Explosives ,PATR 1352(1943) [Relationship betw brisance(detd by sand tests in 200-g and 1700-g... 

Some of the nitrato alcohols are high expls, for example, the 2-nitratoethanol detonated at 187°, the nitratopropanol under the same conditions decompd results of the thermal sensitivity of the nitratobutanol were not reported... 

---