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.     

岩石膨化硝铵炸药的爆破威力研究

研究了岩石膨化硝铵的爆炸性能和爆破威力，在分析岩石爆破机理的基础上，通过与铵梯炸药，铵梯油炸药的爆破性能比较，并根据其自身的爆速高，重量威力大而体积威力稍小的特点，提出进一步提高该炸药爆破威力的技术途径。     

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.     

Effect of Mixing Methods on the Thermal Stability and Detonation Characteristics of Ammonium Nitrate and Sodium Chloride Mixtures

A study has examined the effect of mixing methods on the thermal stability and detonation characteristics of ammonium nitrate (AN) and sodium chloride (NaCl) mixtures. NaCl was mixed with AN by two methods. The thermal stability, detonation velocity and structural properties were investigated by differential scanning calorimetry (DSC), measurement of detonation velocity and X‐ray diffraction (XRD). For the mechanical mixing method, in all tested scope of proportions of NaCl in the mixtures, activation energies increase when the proportion of NaCl increases; for solution mixing method, the activation energies decrease first and then start to increase as the proportion of NaCl increases. The detonation velocity of AN‐NaCl mixtures prepared by two mixing methods also showed different results. The results indicate that the mixing methods significantly affect the thermal stability and detonation characteristics of AN.     

Agriculture Grade Ammonium Nitrate as the Basic Ingredient of Massive Explosive Charges

Prilled ammonium nitrate (AN) is manufactured globally in millions of tons and is mainly used as fertilizer or as the main ingredient of modern mining blasting explosives. The availability of AN poses a serious threat to public security as it enables preparation of massive explosive charges using a simple technology in order to carry out terrorist attacks. This paper examines the option of using agriculture AN manufactured in several Polish plants as the basic ingredient of explosive mixtures with liquid fuels or powdered aluminum. Fuel oil (FO), 2‐EHN and nitromethane were used as liquid fuels. Additionally, the effect of an inorganic additive (dolomite) in AN on the detonation velocity of mixtures of granulated and milled AN with various fuels was examined.     

Determination of Urea Nitrate and Guanidine Nitrate Vapor Pressures by Isothermal Thermogravimetry

Since the bombing of Pan Am Flight 103 over Lockerbie, Scotland in 1988, detection of military explosives has received much attention. Only in the last few years has detection of improvised explosives become a priority. Many detection methods require that the particulate or vapor be available. Elsewhere we have reported the vapor pressures of peroxide explosives triacetone triperoxide (TATP), diacetone diperoxide (DADP), and 2,4,6‐trinitrotoluene (TNT). Herein we examine the vapor signatures of the nitrate salts of urea and guanidine (UN and GN, respectively), and compare them to ammonium nitrate (AN) and TATP using an isothermal thermo‐gravimetric method. The vapor signatures of the nitrate salts are assumed to be the vapor pressures of the neutral parent base and nitric acid. Studies were performed at elevated temperatures (80–120 °C for UN, 205–225 °C for GN, 100–160 °C for AN, and 40–59 °C for TATP), enthalpies of sublimation calculated and vapor pressures extrapolated to room temperature. Reported vapor pressure values (in Pa) are as follows: GN ≪UN <AN ≪TATP 2.66×10⁻¹⁸ 3.94×10⁻⁵ 5.98×10⁻⁴ 24.8     

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.     

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.     

Effective Detonation Synthesis of Cubic Boron Nitride

Successful realization of detonation‐induced h‐BN→c‐BN phase transition requires that a hydrolysis of BN by water from the detonation products is suppressed. For this two kinds of experiments for synthesis of c‐BN were attempted: using benzo‐trifuroxan (with no water in products) as an explosive, in 80% yield; and using the cast 50% TNT+50% RDX charges containing 5–25 wt.‐% of h‐BN powder in order to expend water from the detonation products by a part of BN, and to realize the phase transition in the rest, in 10% yield.     

Detonation Products as a Function of Initiation Strength,ambient gas and binder systems of explosives charges

The way of initiating an insensitive high explosive can influence the start of a detonation reaction remarkably. In order to study the extent of this influence, different boosters and different booster structures for the initiation of explosive mixtures containing TNT and nitroguanidine (NQ) have been used. The experiments have been conducted in a 1.5 m³ containment from which the detonation products could be taken and analyzed. In those cases where we only used a 10 g RDX booster together with a detonation cap no. 8, we had not a complete detonation reaction by initiating cylindrical charges of TNT/NQ and TNT/AN. This means that unreacted TNT was analyzed in the solid residue, mainly consisting of carbon soot. On the other hand, we had a complete detonation using an additional booster of about 18 g detonation sheet, placed on the front side of the cylindrical explosive, having the same diameter as the explosive charge. Another part of the investigations deals with the determination of the influence of different argon pressures on the composition of the detonation gas and the solid residue. Between vacuum and one bar argon a strong change not only of the gas but also of the soot residue was measured. A stronger influence on the products was found using a confinement with glass tubes. The investigation of Al-containing charges exhibited a very different behavior compared with charges without Al. No more influence of vaccum or of different ambient gas pressure could be observed. By investigation of two composite explosive charges (PBX) containing binder systems of different energies and different oxygen balances, a great influence on the reaction of Al was found. The PBX charges with the better O₂-balance containing the energetic GAP-binder reacted nearly completely with the Al, opposite to the charge containing the polyisobutylene (PIB) binder system.     

Vapor Pressure of Explosives: A Critical Review

A critical review of vapor pressure data for military, civilian, and homemade explosives, explosive precursors, and explosive taggants is presented. It gives reference to a large number of papers and reports presenting original vapor pressure measurements and additionally an overview of measurements techniques for vapor pressure measurements and data analysis of vapor pressure measurements. Vapor pressure data, including Clausius–Clapeyron parameters (A and B in: log10(p)=A−B/T), calculated vapor pressure at room temperature, and heat of sublimation or heat of vaporization are included. The following classes of compounds are treated; military explosives (TNT, RDX, HMX, PETN, HNS, TATB, AP), civilian explosives (NG, EGDN, AN), explosive taggants (EGDN, DNMB, 2‐NT, 4‐NT), home‐made explosives (TATP, DADP, HMTD). and explosive precursors [HP(aq), NM, IPN, DNT].     

Relative Explosive Strength of Some Explosive Mixtures Containing Urea and/or Peroxides

Several mixtures, based on urea derivatives and some inorganic oxidants, including also alumina, were studied by means of ballistic mortar techniques with TNT as the reference standard. The detonation pressure(P), detonation velocity(D), detonation energy(Q), and volume of gaseous product at standard temperature and pressure (STP), V, were calculated using EXPLO5 V6.3 thermochemical code. The performance of the mixtures studied was discussed in relation to their thermal reactivity, determined by means of differential thermal analysis (DTA). It is shown that the presence of hydrogen peroxide in the form of its complex with urea (i.e. as UHP) has a positive influence on the explosive strength of the corresponding mixtures which is linked to the hydroxy-radical formation in the mixtures during their initiation reaction. These radicals might initiate (at least partially) powdered aluminum into oxidation in the CJ plane of the detonation wave. Mixtures containing UHP and magnesium are dangerous because of potential auto-ignition.     

Strength of Commercial Explosives

Strength is determined for mixtures of Amatol (79/21 AN/TNT) with various additives and mixtures of ammonium nitrate and aluminum of various compositions. The results obtained and literature data are used to obtain a formula for calculating the relative strength of commercial explosives containing two parameters — explosion heat and volume of explosion products. The strength of mixtures of ammonium nitrate and aluminum (under powerful initiation leading to overcompressed detonation) exceeds the strength of the reference explosive (Amatol) when the aluminum content is 10—40%. In this case, maximum strength is observed for a mixture containing 30% aluminum. The experimental results and calculations using the proposed formula are in satisfactory agreement.     

低爆速膨化硝铵炸药的配方研究

介绍了低爆速膨化硝铵炸药的制备技术特点 ,通过配方设计及试验研究 ,得到低爆速膨化硝铵炸药的最佳配方 ,其性能为爆速约 2 1 0 0 m/ s,传爆距离在 50 m以上 (装药直径 32 mm)     

The Critical Energy of Direct Initiation in Liquid Fuel‐Air and Liquid Fuel‐RDX Powder‐Air Mixtures in a Vertical Detonation Tube

Multiphase cloud detonation is an important but complex process, which has not been fully understood yet. Direct experimental data about the critical initiation energy (CIE) and pressure/velocity revolution of high explosive powder‐based multiphase cloud detonation is not available in the literature. In this paper, propylene oxide (PO), petroleum ether (PE), isopropyl nitrate (IPN), and a mixture of PE/IPN were individually dispersed to form a cloud in a 200 mm×5400 mm vertical detonation tube. Subsequently, this cloud was directly ignited by a high explosive. The critical initiation energy of various mist/air mixtures was measured by the up and down method. Meanwhile, the pressure history was recorded by six sensors along the detonation tube. RDX powder was added to the system and sprayed simultaneously with the liquid fuel to form a three‐phase gas‐liquid‐solid explosive cloud. The detonation pressure and velocity of all three‐phase cases significantly increased while the corresponding critical initiation energy decreased compared to the liquid‐air analogs. The CIE data were found to have a “U”‐shaped curve relationship to the fuel‐air ratio in two‐ and three‐phase systems, the minimum is always on the fuel‐rich side.     

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。     

Laboratory‐Scale Method for Estimating Explosive Performance from Laser‐Induced Shock Waves

A new laboratory‐scale method for predicting explosive performance (e.g., detonation velocity and pressure) based on milligram quantities of material is demonstrated. This technique is based on schlieren imaging of the shock wave generated in air by the formation of a laser‐induced plasma on the surface of an energetic material residue. The shock wave from each laser ablation event is tracked for more than 100 μs using a high‐speed camera. A suite of conventional energetic materials including DNAN, TNT, HNS, TATB, NTO, PETN, RDX, HMX, and CL‐20 was used to develop calibration curves relating the characteristic shock velocity for each energetic material to several detonation parameters. A strong linear correlation between the laser‐induced shock velocity and the measured performance from full‐scale detonation testing has been observed. The Laser‐induced Air Shock from Energetic Materials (LASEM) method was validated using nitrocellulose, FOX‐7, nano‐RDX, three military formulations, and three novel high‐nitrogen explosives currently under development. This method is a potential screening tool for the development of new energetic materials and formulations prior to larger‐scale detonative testing. The main advantages are the small quantity of material required (a few milligrams or less per laser shot), the ease with which hundreds of measurements per day can be obtained, and the ability to estimate explosive performance without detonating the material (reducing cost and safety requirements).     

A Novel Cocrystal Explosive of HNIW with Good Comprehensive Properties

In order to improve the safety of the high explosive 2,4,6,8,10,12‐hexanitrohexaazaisowurtzitane (HNIW), we cocrystallized HNIW with the insensitive explosive DNB (1,3‐dinitrobenzene) in a molar ratio 1 : 1 to form a novel cocrystal explosive. Structure determination showed that it belongs to the orthorhombic system with space group Pbca. Therein, layers of DNB alternate with bilayers of HNIW. Analysis of interactions in the cocrystal indicated that the cocrystal is mainly formed by hydrogen bonds and nitro‐aromatic interactions. Moreover, the thermal behavior, sensitivity, and detonation properties of the cocrystal were evaluated. The results implied that the melting point of the cocrystal is 136.6 °C, which means an increase of 45 °C relative that of pure DNB. The predicted detonation velocity and detonation pressure of the cocrystal are 8434 m s⁻¹ and 34 GPa, respectively, which are similar to that of the reported HNIW/TNT cocrystal, but its reduced sensitivity (H₅₀=55 cm) makes it an attractive ingredient in HNIW propellant formulations.     

Combustion heat of the Al/B powder and its application in metallized explosives in underwater explosions

An underwater explosion test is used to determine the detonation properties of metallized explosives containing aluminum and boron powders. An oxygen bomb calorimeter (PARR 6200 calorimeter, Parr Instrument Company, USA) is used to obtain the heat of combustion of the metal mixtures. As the content of boron powders is increased, the heat of combustion of the metal mixtures increases, and the combustion efficiency of boron decreases. The highest value of the combustion heat is 38.2181 MJ/kg, with the boron content of 40%. All metallized explosive compositions (RDX/Al/B/AP) have higher detonation energy (including higher shock wave energy and bubble energy) in water than the TNT charge. The highest total useful energy is 6.821 MJ/kg, with the boron content of 10%. It is 3.4% higher than the total energy of the RDX/Al/AP composition, and it is 2.1 times higher than the TNT equivalent.     

The Influence of Temperature in the Range from 77 k to 338 k on the Detonation Velocity of RDX/TNT 60/40

The detonation velocity of rods made of RDX/TNT 60/40 was determined with high accuracy in the temperature range from 77 K to 338 K. It was found out that the detonation velocity decreases with increasing temperature. To explain this thermodynamically unusual behaviour it is assumed that the effect of the increase of the detonation velocity with increasing temperature is superposed on the decrease caused by the simultaneous decreasing density of the explosive.