A Low‐Sensitivity Composition Based on FOX‐7

1,1‐Diamino‐2,2‐dinitroethene (DADNE, FOX‐7) is considered to be an explosive combining comparatively high performance and low sensitivity. In the present study, FOX‐7 has been evaluated as a possible replacement of RDX in TNT‐based melt‐cast compositions. A composition containing FOX‐7, TNT, Al and wax, and a method of preparing it were proposed. Its sensitivity to impact, friction, shock wave, jet impact, fast heating, and its thermal stability were tested. Some detonation parameters like the detonation pressure, velocity and heat were measured. Moreover, the Gurney velocity, the so‐called effective exponent of the expansion isentrope and the JWL equation of state of the detonation products were determined from the results of a cylinder test. The detonation characteristics were compared with that obtained for cast TNT.     

Partial Reparametrization of the BKW Equation of State for DNAN‐Based Melt‐Cast Explosives

DNAN‐based melt‐cast explosives are a type of new, insensitive munitions (IM) explosives. Quickly determining munitions’ explosive properties is extremely important during the formulation design stage. The aim of this study was to partially reparameterize BKW‐EOS (only β and κ were reparameterized on the basis of the parameters (α , β , κ , and θ ) of classical BKW‐RDX set and BKW‐TNT set) to more accurately predict the properties of DNAN‐based melt‐cast explosives. A new set of parameters β and κ was obtained (β =0.19, κ =9.81) according to measured detonation velocity and detonation pressure for ideal DNAN‐based melt‐cast formulations (DNAN/RDX and DNAN/HMX). For non‐ideal DNAN‐based melt‐cast formulations (DNAN/RDX/Al and DNAN/HMX/Al), aluminum oxidation degree was first determined according to the measured detonation heat; then, another new set of parameters β and κ was obtained in the same way as the ideal formulations (β =0.24, κ =8.5). The predicted detonation properties with BKW reparametrization for DNAN‐based melt‐cast explosives agreed with the measured data.     

Effects of Aluminum Content on TNT Detonation and Aluminum Combustion using Electrical Conductivity Measurements

To improve the understanding how aluminum contributes in non‐ideal explosive mixtures, cast‐cured formulations were analyzed in a series of electrical conductivity experiments. Five types of TNT‐based aluminized explosives, with aluminum mass fractions from 0 % to 20 % were considered in this study. The electrical conductivity of the detonation products in aluminized explosives was measured using an improved conductivity measurement method. The conductivity measurement results show that the detonation process of TNT‐based aluminized explosives can be divided into two stages: the first stage is the detonation reaction of TNT, and the second stage is the combustion reaction of aluminum with the detonation products. In the first stage, the duration of the TNT detonation increases with increased aluminum content; examination of the peak conductivities of the explosives with various aluminum contents indicated that a higher aluminum content is associated with a lower peak conductivity. Additionally, the ignition time of Al in the second stage is also determined. This work not only presents a means for studying the detonation process of aluminized explosives at 0–2.21 μs, but it also verified the relationship between the aluminum content and electrical conductivity in detonation products.     

Verification of the Explosive Quality of TH‐5

This paper reports the characteristics of the explosive TH‐5, recycled (recovered) trinitrotoluene (TNT) with max. 5 wt‐% of hexogen (RDX). The explosive TH‐5 was obtained by delaboration of warheads and melting of explosive charges based on TNT and RDX and by separation (extraction) of high explosive components. The thermal characteristics of pure (virgin) TNT and RDX, and recycled explosive TH‐5 are determined by differential scanning calorimetry. The possibility of processing TH‐5 by pressing and casting is also examined. The comparative analysis of sensitivity of TH‐5 and TNT to friction is determined, as well as compressibility of explosives, and the detonation velocity of pressed and cast charges. Based on the analysis of experimental results, the defense standard requirements for the quality of TH‐5 are defined and possibility of practical application of explosive TH‐5 was estimated.     

1,3,5‐Trinitroperhydro‐1,3,5‐triazine (RDX)‐Based Sheet Explosive Formulation with a Hybrid Binder System

A plastic‐bonded explosive (PBX) in the form of a sheet was formulated comprising of 1,3,5‐trinitroperhydro‐1,3,5‐triazine (RDX) and an hybrid binder system containing a linear thermoplastic polyurethane and a fluoroelastomer (Viton). The effect of a fluoroelastomer on the explosive as well as mechanical properties and thermal behavior of sheet explosive formulations were investigated and compared with a control formulation containing 90 % of RDX and 10 % of natural rubber (ISNR‐5). The replacement of 10 % natural rubber by a hybrid binder system led to an increase in the velocity of detonation (VOD) of the order of 250–950 m s⁻¹ and better mechanical properties in terms of tensile strength (1.9–2.5 MPa) compared to the control formulation (RDX/ISNR‐5 (90/10)). The compatibility of ingredients and thermal decomposition kinetics of selected sheet explosive formulations were investigated by vacuum stability tests and differential scanning calorimetry (DSC). The results suggested better compatibility of RDX with the hybrid binder system (polyurethane/Viton), which is useful to reduce potential hazards in handling, processing, and storage.     

Evaluation of Plastic Bonded Explosive (PBX) Formulations Based on RDX,Aluminum, and HTPB for Underwater Applications

Aluminized high explosives are known to give better underwater performance. All explosive formulations for underwater targets are filled into warheads and shells by casting method. TNT, a high explosive is used as casting medium due to its lower melting point. Plastic bonded explosives are fast replacing TNT‐based high explosive formulations for the reasons that they are more insensitive and low vulnerable explosives with better shelf life. Few aluminized plastic bonded explosive formulations based on RDX, aluminum, and HTPB have been processed, varying the aluminum content from 0 to 35% and evaluated underwater. The present paper discusses the experimental methodology adopted to evaluate the above formulations for their ballistic parameters, viz., peak over pressure and impulse. Explosion bulge tests have been conducted with each explosive formulation and extent of bulge in test plates is presented and compared with a standard underwater explosive, viz., HBX‐3.     

Modification of W/O Emulsions by Demilitarized Composition B

A series of W/O emulsion explosives containing 30–50 wt‐% of the demilitarized mixture RDX/TNT (Composition B 50/50) was prepared. Detonation velocities and relative explosive strengths of these mixtures were determined and their detonation characteristics were calculated according to the EU standard methods for commercial explosives. Thermal reactivities of the most reactive components of these W/O mixtures were examined by means of differential thermal analysis and outputs were analyzed according to the Kissinger method. The reactivities, expressed as the E_a ⋅ R⁻¹ slopes of the Kissinger relationship, correlate with the squares of the detonation velocities of the corresponding explosive mixtures. It was found that fortification of the W/O emulsions by the demilitarized mixture RDX/TNT allows modification of detonation velocities of the resulting emulsion explosives within relatively broad limits. However, the effect of this admixture on the relative explosive strength is not well defined. Nevertheless, fortification in this sense can give rock‐blasting explosives with a performance on the level of industrial powdered amatols.     

老化对TNT基熔铸炸药性能的影响

为了研究老化对炸药性能的影响,对自然贮存的3种熔铸炸药TNT／RDX、TNT／RDX／Al和 TNT／HMX／Al进行了加速老化试验。通过扫描电镜、真空安定性试验研究了老化前后3种炸药的微观形貌和安全性能,并测试了老化前后3种炸药的感度和爆速。结果表明,老化后炸药颜色变深,体积膨胀,质量变轻。样品的放气量小于2 mL／g ,热感度变化也较小。机械感度的变化与炸药组分和老化方式有关。TNT／RDX的爆速随着贮存时间的增加而降低,与整体加速老化情况一致,TNT／RDX／Al和 TNT／HMX／Al的爆热随贮存时间的增加变化趋势相反,说明两者老化机理可能不同。     

Ageing of Australian DNAN Based Melt‐Cast Insensitive Explosives

2,4‐Dinitroanisole (DNAN) is a new melt‐cast matrix ingredient that replaces traditional TNT in TNT‐based melt‐cast explosives. Aside from sensitiveness improvements, the use of DNAN allows for the continued operation of existing melt‐cast facilities (for example the Australian Munitions plants located at Mulwala and Benalla) without the need for major plant modifications. Researchers at Defence Science and Technology Group (DST Group) have developed several DNAN based formulations that have been extensively characterized. In an effort to better understand the ageing properties of these formulations, an accelerated ageing program was undertaken. Testing was conducted under two different ageing conditions; the first test condition was conducted at a constant 60 °C with ambient humidity and the second test condition was the A2 diurnal cycle (representative of hot dry climates). Analysis of the formulation density, sensitiveness, mechanical and thermal properties was made at three‐month intervals for a period of 12 months and results compared with conventional explosives similarly aged. For all DNAN‐based formulations there was negligible change in impact, friction, electrostatic discharge, and thermal testing over time. These results highlight the ability of the ARX formulations to diurnal temperature cycling and to hold favorable sensitiveness properties to various stimuli.     

Semi‐Closed Investigations of New Aluminized Thermobaric and Enhanced Blast Composites

The investigations of new aluminum‐enriched RDX‐based composites belonging to the thermobaric and enhanced blast explosive formulations were undertaken. In a semi‐closed bunker, the blast wave and the thermal characteristics of pressed and layered charges made from the composites are determined. The study includes the blast wave history registrations as well as the determination of the overpressure peaks and the specific impulses of the incident blast wave. The total impulses have been estimated for a period of 60 ms. Since the composites are supposed to be volumetric, the explosion light outputs and the fireball temperatures were also investigated. The results obtained for the composite charges were compared with the blast performances and fireball temperatures of TNT and phlegmatized RDX charges of the same mass. Also differences between the pressed and the layered composite charges prepared from the same composites were observed and explained. The effect of the aluminum particle size was checked. Discussion of the results and conclusions about the aluminum combustions during the explosions of such charges were presented.     

Effect of inert plasticizers on mechanical,thermal, and sensitivity properties of polyurethane‐based plastic bonded explosives

Mechanical, thermal, and sensitivity properties of plastic bonded explosives (PBX) depend on the type of ingredients in their formulation. Aim of the work is to develop aluminized cast PBX formulations and process conditions by using alternative inert plasticizers to have similar or better properties than PBXN‐109 without compromising sensitivity properties. Although very small portion of total production of plasticizers is used for solid rocket propellant and explosive formulations, they play very significant role in that area. Both inert and energetic plasticizers have involved propellant and explosive formulations to improve process parameters, mechanical properties, and even insensitivity properties of them. Isodecyl pelargonate and dioctyl adipate are the most preferred inert plasticizers in polyurethane based thermoset propellant and explosive formulations. In addition to them, diisononyl adipate and diisononyl phthalate were used and screened as inert plasticizer candidates for aluminized cast PBX formulations. Mechanical, thermal, and sensitivity properties of PBX formulations were studied and compared in detail. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40907.     

Preparation and Characterization of Nanoenergetics Based Composition B

Explosive compositions employing nanoscale crystals of high explosives (i. e., nanoenergetics) have demonstrated reduced sensitivities to external stimuli. Until recently, the investigated formulations were limited to plastic bonded explosives. Explosives that are normally melt‐cast also would benefit from the use of nanoenergetics. However, the integration of nanoenergetics into the melt‐cast process is challenging due to the large surface area and solubility associated with nanoenergetics. In this work, we explored the preparation of nanoenergetics‐based Composition B (Comp B), a widely used melt‐cast explosive, by spray drying followed by mechanical compaction. The Comp B molding powder obtained from spray drying was characterized by scanning electron microscopy (SEM) and X‐ray diffraction (XRD). The structure and the shock sensitivity of the compacted nanoenergetics‐based Comp B (N‐Comp B), both as‐prepared and thermally cycled, was also studied using melt‐cast Comp B as the reference material. The characterization shows that N‐Comp B consisting of nanoscale cyclotrimethylenetrinitramine (RDX) and trinitrotoluene (TNT) contains mostly nanoscale voids but has a large number density. Reduced shock sensitivity was observed from N‐Comp B, attributed to the elimination of large voids. But the decrease seems to have been constrained by the large number density of voids. Thermal cycling induced significant structural change, i. e., the increase of both void size and the crystal size, causing an increase in sensitivity. Procedures are proposed to further reduce the sensitivity and enhance the thermal stability of N‐Comp B.     

Insensitive High Explosives II: 3,3′‐Diamino‐4,4′‐azoxyfurazan (DAAF)

This paper reviews the synthesis, properties, performance, and safety of the insensitive explosive 3,3′‐diamino‐4,4′‐azoxyfurazan (DAAF, C₄H₄N₈O₃), CAS‐No. [78644‐89‐0], and 18 formulations based on it. Though having a moderate crystal density only, DAAF offers high positive heat of formation and hence superior performance when compared with TATB. It is friction and impact insensitive but is more sensitive to shock than TATB and has an exceptionally small critical diameter and performs very well at low temperatures unlike other insensitive explosives. 39 references to the public domain are given. For Part I see Ref. [1].     

RDX基铝薄膜炸药与铝粉炸药水下爆炸性能比较

为了减少铝粉炸药在生产过程中因铝粉对环境污染,降低铝粉炸药的撞击感度,提高含铝炸药的成型性及力学性能,将RDX用铝薄膜分层包裹得到新型的铝薄膜混合炸药。将铝薄膜混合炸药与铝粉炸药进行水下爆炸实验与爆速实验,得到两种炸药的爆速与压力时程曲线,经过分析计算得到两种炸药的压力峰值、冲量、冲击波能、气泡脉动周期与气泡能。结果表明：铝薄膜炸药药柱的轴向为RDX与铝薄膜独立贯通的结构,有利于降低混合炸药中添加物对基体炸药爆轰波传播的影响,从而使铝薄膜混合炸药的爆速高于铝粉炸药,导致铝薄膜炸药的冲击波损失系数高于铝粉炸药,使铝薄膜混合炸药的总能量、比气泡能与铝粉炸药相当情况下,其比冲击波能却降低了10.16%～10.33%,计算过程说明铝薄膜混合炸药的C-J压力计算公式具有合理性。     

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

We 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.     

EAK基熔铸分子间炸药的能量和撞击感度

通过水下爆炸试验研究了RDX和HMX对EAK基熔铸分子间炸药水下能量的影响。结果表明,RDX和HMX对EAK基混合炸药起到明显的增能作用,但对含铝和非含铝体系有不同的作用效果。爆速和撞击感度测定表明,EAK—RDX混合炸药爆轰的理想化程度和稳定性及撞击感度随RDX含量的增加而增加。从能量和撞击感度两个方面综合考虑,RDX的较佳加入量应为20％～30％。     

Bishydrazinium and Diammonium Salts of 4,4′,5,5′‐Tetranitro‐2,2′‐biimidazolate (TNBI): Synthesis and Properties

The diammonium ( 1 ) and bishydrazinium ( 2 ) salts of 4,4′,5,5′‐tetranitro‐2,2′‐biimidazolate (TNBI) were synthesized and their physical properties as well as predicted explosive performance characteristics are described. These dianionic salts are easily formed in good yields by reaction of TNBI with aqueous solutions of the cationic species. TNBI is synthesized from 2,2′‐biimidazole, which is ultimately synthesized by the condensation of aqueous glyoxal with ammonium acetate. The compounds were characterized by NMR spectroscopy, vibrational (FT‐IR and Raman) spectroscopy, elemental analysis, thermal analysis (DSC, VTS and calorimetry), and small scale safety testing (impact, friction, ESD). The measured densities and heats of formation are reported. The materials show promise for use in IM explosive and propellant formulations due to the combination of their calculated performances, thermal stability and insensitivity to stimuli.     

Degradation of TNT,RDX, and HMX Explosive Wastewaters Using Zero‐Valent Iron Nanoparticles

The high‐energy explosives 2,4,6‐trinitrotoluene (TNT), hexahydro‐1,3,5‐trinitro‐1,3,5‐triazine (RDX), and the high melting explosive octahydro‐1,3,5,7‐tetranitro‐1,3,5,7‐tetrazocine (HMX) are common groundwater contaminants at active and abandoned munitions production facilities causing serious environmental problems. A highly efficient and environmentally friendly method was developed for the treatment of the explosives‐contaminated wastewaters using zero‐valent iron nanoparticles (ZVINs). ZVINs with diameters of 20–50 nm and specific surface areas of 42.56 m² g⁻¹ were synthesized by the co‐precipitation method. The explosives degradation reaction is expressed to be of pseudo first‐order and the kinetic reaction parameters are calculated based on different initial concentrations of TNT, RDX, and HMX. In addition, by comparison of the field emission scanning electron microscopy (FE‐SEM) images for the fresh and reacted ZVINs, it was apparent that the ZVINs were oxidized and aggregated to form Fe₃O₄ nanoparticles as a result of the chemical reaction. The X‐ray diffraction (XRD) and X‐ray absorption near edge structure (XANES) measurements confirmed that the ZVINs corrosion primarily occurred due to the formation of Fe₃O₄. Furthermore, the postulated reaction kinetics in different concentrations of TNT, RDX, and HMX, showed that the rate of TNT removal was higher than RDX and HMX. Furthermore, by‐products obtained after degradation of TNT (long‐chain alkanes/methylamine) and RDX/HMX (formaldehyde/methanol/hydrazine/dimethyl hydrazine) were determined by LC/MS/MS, respectively. The high reaction rate and significant removal efficiencies suggest that ZVINs might be suitable and powerful materials for an in‐situ degradation of explosive polluted wastewaters.     

Potential Use of CL‐20 in TNT/ETPE‐Based Melt Cast Formulations

An attempt was made to introduce CL‐20 in a TNT/energetic thermoplastic elastomer (ETPE)‐based melt cast formulation, to obtain an insensitive composition with reduced adverse environmental properties. A loading limit of 42% w/w of CL‐20 in melted TNT was observed, while it should have been around 70%. This paper describes the investigation that was undertaken to understand the observed phenomena. It was demonstrated that CL‐20 undergoes structural alterations in melted TNT. The relative solubility of CL‐20, RDX and HMX in melted TNT was determined and the α‐, β‐, γ‐ and ε‐CL‐20 were prepared and characterized using Raman spectroscopy and DTA. CL‐20 was mixed in melted TNT, as much as 4.2 g of CL‐20 dissolved in 100 g of TNT. This allowed a transformation from ε to β‐CL‐20 and a modification of CL‐20 particle size and distribution. The later modification induced a raise in CL‐20 specific surface and was responsible for the loading limit, while the transformation to β‐CL‐20 caused an increase in sensitivity and a decrease in density. This indicates that the use of CL‐20 in TNT melt cast is not promising. Our study also showed that CL‐20 is sensitive to morphological transformations, which should be taken into consideration in future processing using this compound.     

Highly Thermal Stable TATB‐based Aluminized Explosives Realizing Optimized Balance between Thermal Stability and Detonation Performance

In this work, a series of TATB‐based aluminized explosives were formulated from 1, 3, 5‐triamino‐2, 4, 6‐trinitrobenzene (TATB), aluminum powders and polymeric binders. The thermal stability, heat of detonation, detonation velocity and pressure of the TATB based aluminized (TATB/Al) explosives were systematically investigated by cook‐off, constant temperature calorimeter, electrometric method and manganin piezo resistance gauge, respectively. The selected PBX‐3 (70 wt% TATB/25 wt% Al/5 wt% fluorine resin) achieved optimized balance between thermal stability and detonation performance, with the thermal runaway temperature around 583 K. The thermal ignition of TATB‐based aluminized explosive occurred at the edge of the cylinder according to the experimental and numerical simulations. Moreover, the critical thermal runaway temperature for PBX‐3 was calculated based on the Semenov's thermal explosion theory and the thermal decomposition kinetic parameters of the explosive, which was consistent with the experimental value.