Energetic Filler Research Articles

Efficiency of perchlorate consumption in road flares, propellants and explosives

When an explosive detonates or a propellant or flare burns, consumption of the energetic filler should be complete but rarely is, especially in the presence of large amounts of non-combustible materials. Herein we examine three types of perchlorate-containing devices to estimate their potential as sources of contamination in their normal mode of functioning. Road flares, rocket propellants and ammonium nitrate (AN) emulsion explosives are potentially significant anthropogenic sources of perchlorate contamination. This laboratory evaluated perchlorate residue from burning of flares and propellants as well as detonations of ammonium nitrate emulsion explosives. Residual perchlorate in commercial products ranged from 0.094 mg perchlorate per gram material (flares) to 0.012 mg perchlorate per gram material (AN emulsion explosives). The rocket propellant formulations, prepared in this laboratory, generated 0.014 mg of perchlorate residue per gram of material.

Technology of Foamed Propellants

AbstractFoamed propellants are based on crystalline explosives bonded in energetic reaction polymers. Due to their porous structures they are distinguished by high burning rates. Energy content and material characteristics can be varied by using different energetic fillers, energetic polymers and porous structures. Foamed charges can be produced easily by the reaction injection moulding process. For the manufacturing of foamed propellants a semi‐continuous remote controlled production plant in pilot scale was set up and a modified reaction injection moulding process was applied.

Synthesis and Characterization of 4,4′,5,5′‐Tetranitro‐2,2′‐Bi‐1H‐imidazole (TNBI)

AbstractWe synthesized 4,4′,5,5′‐tetranitro‐2,2′‐bi‐1H‐imidazole (TNBI), which may serve as a new energetic filler for high explosive formulations. TNBI was synthesized by treating an excess amount of sodium nitrate with 2,2′‐bi‐1H‐imidazole (BI), which was produced from glyoxal and ammonia gas. The overall synthetic yield was 32%. The synthesized TNBI was characterized by performing various chemical analyses including NMR, IR, and CHN analyses. Small scale sensitivity tests were carried out at both research institutes (ADD and ARDEC). The sensitivity results varied from ‘more sensitive than RDX’ to ‘substantially less sensitive than RDX’ according to the purity and conditions of the test samples. Based on our careful characterizations, this large variation in sensitivity was attributed to the moisture content that was present in the test samples due to a hygroscopic nature of TNBI. We also found that the hygroscopic nature of TNBI changed significantly due to the amount of impurities, especially sulfates.

Improvised Explosive Devices: Pipe Bombs

Abstract The fragments from 56 pipe bombs were collected (average recovery 87%), counted, weighed, sorted, and photographed. The matrix examined included eight energetic fillers, two initiation systems, three types of pipe, and several degrees of fill. The matrix and results are summarized in Table 1. For identical devices, the overall fragmentation pattern was surprisingly reproducible. The fragmentation patterns are presented in photos, but they are also reduced to numerical evaluators. A particularly useful evaluator is the fragment weight distribution map (FWDM) which describes explosive power with a single variable—the slope. This value is independent of device size and percent recovery. We believe this database of 56 pipe bombs is the largest controlled study of these devices. This study demonstrates the possibility that, even in circumstances where chemical residue cannot be found, sufficient evidence is present in the pipe fragments to identify the nature of the energetic filler.

Radiation cure of explosive/propellant formulations

Abstract The feasibility of radiation curing energetic compositions has been demonstrated. Binders consisting of vinyl-terminated polybutadieneacrylonitrile copolymer (VTBN) and a combination of styrene and 2-hydroxyethyl methacrylate have been cured using x-rays at a dose of 1.2 × 106 roentgen to give flexible, rubbery solid materials with rupture stress of 0.8 to 8.3 MPa and strain of 130–230 percent at 25°C. Irradiation of RDX (1,3,5-trinitro-l,3,5-triazacyclohexane) and HMX (1,3,5,7-tetranitro-l,3,5,7-tetrazacyclooctane) a t the 1.2 × 106 roentgen dose level caused no measurable ni tramine decomposition. The VTBN binder system loaded with 70% nitramine energetic filler was cured by irradiation (1.2 × 106 roentgen) t o give rubbery solids with 2.2–2.8 MPa stress a t rupture and nearly 100% strain (25°C). The filled systems display Taliani slopes, nitramine phase transitions and decomposition temperatures which are well within normal 1imits for explosives and propellants.