Semtex explosive

Four nitrosamines, seven nitramines, three nitroesters and the explosives Semtex 10 and Composition B have been investigated by TGA. Linear dependence was confirmed between the position of the TGA onsets, as defined in the sense of Perkin-Elmer s TGA-7 standard program, and the samples weights. The slope of this dependence is closely related to the thermal reactivity and molecular structure. The intercept values of the dependence correlate with the autoignition temperatures and with the critical temperatures of the studied compounds, without any clear influence from molecular structure. Results show that Semtex 10 exhibits approximately the same thermostability as its active component pentaerythrityl tetranitrate (PETN, 274). Results also show that TGA data for Composition B do not correlate with analogous data for pure nitramines564. 

While undeniably powerful and possessing all the qualities one would expect of a plastic explosive, Semtex has one serious flaw—-a tendency to exude the vegetable oil plasticizer at elevated temperatures. In a recent case at London s Heathrow Airport, an alert security officer noticed an oily stain on a passsengcris bag and suspected it was from Semtex. Security officials searched the bag, found the bomb set to go off... 

Standard Explosives Semtex PETN explosive composition... 

W-W 748, IMR 4831), and plastic explosives (Semtex, C4, Detasheet, Tovex). Compositional differences among reloading powders were found in products from different manufacturers, but also between powders from the same producers. The reasons for these differences were discussed by the authors. 

The above statement, widely believed and propagated by the news media, is false. Semtex is not a superexplosive possessing extraordinary qualities and more power than other types of plastic explosives. Semtex s explosive power comes from a 50-50 mixture of PETN and RDX. PETN has a relative effectiveness of 1.66 RDX has a relative effectiveness of 1.5. Semtex contains 89 percent explosive and 11 percent inert plasticizing material. C-4, the U.S. Army standard plastic explosive, is 91 percent RDX and 9 percent inert plasticizing material. Essentially, Semtex and C-4 have the same power. 

Pierrini et al. [108] discuss issues surrounding the interpretation of isotope ratio data and present a continuous likelihood ratio approach for the evaluation of data generated from the analysis of the plastic explosive Semtex (RDX/PETN). The authors highlighted the need for large international isotope ratio databases in order for this approach to work. 

Pentaerythritol tetranitrate PETN C5H8N4O12 316.14 Detonators, sheet explosives, Semtex, blasting caps... 

The investigation into the sabotage of Pan Am Flight 103, which left 269 dead, indicated that the explosive used was Semtex H, a plasticized mixture of hexahydro-l,3,5-trinitro-s-triazine and pentaerythritol tetranitrate, and that the amount used was half the quantity that the fledgling technique of Thermal Neutron Analysis (TNA) was designed to detect. Although the placement of the explosive device was fortuitous (from the terrorists point of view) and the suitcase had not been screened by TNA, this event killed the TNA prototype program. 

Plastic explosives contain one or more of the explosives listed above, moulded in an inert, flexible binder. Because powders do not readily hold a shape and TNT is the only common melt-castable explosive, most of the explosive powders (RDX, HMX, PETN, 1,3,5-triamino-2,4,6-trinitrobenzene (TATB)) are plasticized to make a mouldable material, for example, C-4, Semtex H, PE4, sheet explosive. A variety of plasticizers are added, but the maximum level is usually 10-15% because most plasticizers are inert and would degrade explosive output. Plastic explosives were originally developed for convenient use in military demolitions but have since been widely used in terrorist bombs. For detection techniques that rely on vapour signatures, such as canine olfaction, it is worth considering that the plasticizer is much more volatile than the explosive component. 

Figure 9 shows the LC/MS-ESI mass chromatograms of a 25pg/)J.L Semtex sample (a plastic explosive containing RDX and PETN) with post-column introduction of ammonium nitrate [17]. FIPLC separation was achieved with a CIS column (100 X 2.1mm, 5 0,m particle size), using an isocratic mobile phase of methanol-water (70 30), at a flow rate of 150 0,L/min. 

With a focus on trace forensic detection of explosives, especially for use in counterterrorism and to counter narcotics investigations, Fetterolf et al. [75] evaluated the use of ion mobility-mass spectrometry for explosives determinations. In this, explosives residues were collected on a membrane filter by a special attachment on a household vacuum cleaner. Although subsequent thermal desorption and analysis required only 5 s, fimits of detection for most common explosives were as low as 200 pg. The persistence of explosives on hands and transfer to other surfaces were also examined as were post-blast residues of NG on fragments of improvised explosive devices constructed with double-based smokeless powder. Finally, postblast residue from C-4, Semtex, and other explosives was found by IMS analyses on items of forensic and evidentiary value. These few out of many examples demonstrate that mobihty spectrometers are well suited tools for laboratory and on-site investigations, before and after the use of explosives. 

Pentaerythritol tetranitrate (PETN) (3) is a powerful explosive which exhibits considerable brisance on detonation (VOD 8310 m/s at = 1.77 g/cm ). It is the most stable and least reactive of the common nitrate ester explosives. The relatively high sensitivity of PETN to friction and impact means that it is usually desensitized with phlegmatizers like wax and the product is used in detonation cord, boosters and as a base charge in detonators. Pentaerythritol tetranitrate can be mixed with synthetic polymers to form plastic bonded explosives (PBXs) like detasheet and Semtex-IA. A cast mixture of PETN and TNT in equal proportions is known as pentolite and has seen wide use as a military explosive and in booster charges. The physical, chemical and explosive properties of PETN commend its use as a high explosive. 

Semtex Plastic explosive containing cyclonite (RDX) and pentaerythri-toltetranitrate (PETN), made in Czech Republic. 

HMX-based PBXs were developed for projectiles and lunar seismic experiments during the 1960s and early 1970s using Teflon (polytetra-fluoroethylene) as the binder. PBXs based on RDX and RDX/PETN have also been developed and are known as Semtex. Development is continuing in this area to produce PBXs which contain polymers that are energetic and will contribute to the explosive performance of the... 

Analyzed explosives included TNT, RDX, HMX, PETN, TATP, and the plastic explosives C-4, Semtex-H, and Detasheet. Limits of detection were in subnanogram to subpicogram range. 

Since about 1950 polymer-bonded (or plastic-bonded) explosives (PBX) have been developed in order to reduce sensivity and to facilitate safe and easy handling. PBX also show improved processibility and mechanical properties. In such materials the crystalline explosive is embedded in a rubber-like polymeric matrix. One of the most prominent examples of a PBX is Semtex. Semtex was invented in 1966 by Stanislav Brebera, a chemist who worked for VCHZ Synthesia in Semtin (hence the name Semtex), a suburb of Pardubice in the Czech Republic. Semtex consists of varying ratios of PETN and RDX. Usually polyisobutylene is used for the polymeric matrix, and phthalic acid n-octylester is the plasticizer. Other polymer matrices which have been introduced are polyurethane, polyvinyl alcohol, PTFE (teflon), Viton, Kel-F and various polyesters. 

RDX forms orthorhombic crystals with a melting point of 206 Celsius. 1 Gram dissolves in 25 milliliters of acetone, but its solubility in alcohol, ether, ethyl acetate, and glacial acetic acid is even less. It is insoluble in water, carbon tetrachloride, and carbon disulfide. RDX is one of the most important military explosives known to man. It is highly versatile, being resistant to heat, shock and percussion, and is capable of being alloyed with many different secondary explosives. RDX is very well known in several of the most important explosives compositions. These compositions include semtex, C4, and composition B, all of which are widely used in military operations. RDX is by far one of the most important explosives in occurrence, and it is manufactured on an industrial scale. 

Semtex is a powerful plastic explosive that is more sensitive to initiation than Composition C. As was mentioned in the safety section of this book, respiratory protection rr used when performing this procedure, as RDX dust is toxic. 

Semtex has earned a reputation as the explosive of choice among terrorists and in Hollywood. Terrorists use this Czechoslovakian plastic explosive because their Eastern Bloc sponsors gave it to them. Hollywood types use it because terrorists do, and writers and directors believe Semtex to be a superexplosive possessing extraordinary power unmatched by other explosives. Knowledgeable terrorists know better. 

Semtex is the plastique most widely used by terrorists around the world. In what is the first book to focus solely on Semtex, noted demolitions expert Seymour Lecker sets the record straight about this powerful but misrepresented terror weapon. He tells you what it will and won t do, its strengths and its limfkations, and how it compares with its U.S. counterpart, C-4. Lecker also details the explosiveness, materials, manufacturing procedures, storage characteristics, dangers, and conditions of use. Find out the vital facts about Semtex before you re confronted with a situation where what you don t know can hurt you. Homemade Semtex is for information purposes only. 

But Semtex tends to bleed its plasticizers, leaving a visible oily stain. Additionally, when a plastic explosive extrudes its plasticizers, it loses some of its plastic quality. C-4... 

Three ingredients are used to manufacture improvised Semtex powdered RDX, powdered PETN, and a plasticizer. From personal experience, I recommend using petroleum jelly as the plasticizer when improvising plastic explosives. 

Hobbs J. R., Analysis of Semtex Explosives, Adv. Anal. Detect. Explos. Proc. 4th Inter. Symp. Anal. Detect. Explos. September 7-1., 1992 Jerusalem, Israel, Yinon J., Ed. Kluwer Academic Publishers Dordrecht, Holland 409-427, 1992. 

Semtex A nitrogen-based stable odourless plastic explosive. 

A Renishaw Raman Microspectrometer, model RM-2000 equipped with Leica microscope, lOx magnification objective and CCD detector was used to study the signal enhancement of analytes deposited on stainless steel (ss) plates by the direct application of silver colloids. The spectra were obtained in the range of 600-1800 cm nsing one acquisition and 3 s of integration time (Fig. 1). Spontaneous Raman spectra were obtained from pentaerythritol tetranitrate (PETN) high explosive (HE) and from SEMTEX, a PETN based explosive formulation. PETN was synthesized according to the method described by Urbanski (16). 

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