Compatibility Study of DNTF with Some Insensitive Energetic Materials and Inert Materials

The compatibility of 3,4-dinitrofurazanfuroxan (DNTF) with insensitive energetic materials and inert materials was studied in detail using differential scanning calorimetry (DSC). 2,4,6-Trinitrotoluene (TNT), 2,4,6-triamino-1,3,5-trinitrobenzene (TATB), 3-nitro-1,2,4-triazol-5-one (NTO), 2,6-diamino-3,5-dinitropyrazine-1-oxide (LLM-105), 2,6-diamino-3,5-dinitropyridine-1-oxide (ANPyO), and 5-amino-1H-tetrazole nitrate (5-ATEZN) are used as insensitive energetic materials, and polymer(vinyl acetate) (PVAC), hydroxyl-terminated polybutadiene (HTPB), dinoctylsebacate (DOS), 2,4-dinitrotoluene (DNT), and wax are used as inert materials. The results show that DNTF/TNT and DNTF/5-ATEZN possess good compatibility, DNTF/NTO and DNTF/TATB have moderate compatibility, and the compatibility of DNTF/LLM-105 and DNTF/PVAC is poor; in addition, DNTF/ANPyO, DNTF/HTPB, DNTF/DNT, DNTF/DOS, and DNTF/wax have bad compatibility.     

Sensitivity of 2,6-Diamino-3,5-Dinitropyrazine-1-Oxide

ABSTRACT

The thermal and shock sensitivities of plastic bonded explosive formations based on 2,6-diamino-3,5-dinitropyrazine-1-oxide (commonly called LLM-105 for Lawrence Livermore Molecule #105) are reported. The One-Dimensional Time to Explosion (ODTX) apparatus was used to generate times to thermal explosion at various initial temperatures. A four-reaction chemical decomposition model was developed to calculate the time to thermal explosion versus inverse temperature curve. Three embedded manganin pressure gauge experiments were fired at different initial pressures to measure the pressure buildup and the distance required for transition to detonation. An Ignition and Growth reactive model was calibrated to this shock initiation data. LLM-105 exhibited thermal and shock sensitivities intermediate between those of triaminotrinitrobenzene (TATB) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazine (HMX).     

The Temperature-Dependent Thermal Expansion of 2,6-Diamino-3,5-dinitropyrazine-1-oxide Effected by Hydrogen Bond Network Relaxation

The temperature-dependent thermal expansion of 2,6-diamino-3,5-dinitropyrazine-1-oxide (LLM-105) was investigated by using powder X-ray diffraction (PXRD) together with Rietveld refinement to estimate the dimension at a crystal lattice level. In the temperature range of 30–200°C, the coefficient of thermal expansion (CTE) of LLM-105 is temperature dependent, which is different from other explosives, such as hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), 2,2′,4,4′,6,6′-hexanitrostilbene (HNS) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), with constant CTEs. The results of temperature-dependent infrared (IR) spectra indicated that the intermolecular hydrogen bond network relaxes with increasing temperature, which results in temperature-dependent thermal expansion. In this work, more accurate CTEs for LLM-105 crystals are obtained and the effects of the hydrogen bond network on the thermal expansion are further clarified. These results are beneficial to the design of materials with structural peculiarities and as-expected thermal expansion to satisfy different application requirements.     

Compatibility Study of Dihydroxylammonium 5,5′-Bistetrazole-1,1′-diolate (TKX-50) with Some Energetic Materials and Inert Materials

Dihydroxylammonium 5,5′-bistetrazole-1,1′-diolate (TKX-50) emerged as a novel energetic material with low sensitivity and excellent calculated detonation performance. The compatibility of TKX-50 with nitrocellulose (NC), an NC/NG (nitroglycerine) mixture (mass rate: 1.25:1), 2,4-dinitroanisole (DNAN), 2,4,6-trinitrotoluene (TNT), cyclotrimethylenetrinitramine (RDX), ammonium perchlorate (AP), hexanitroethane (HNE), cyclotetramethylenetetranitramine (HMX), hexanitrohexazaisowurtzitane (CL-20), glycidyl azide polymer (GAP), hydroxyl-terminated polybutadiene (HTPB), aluminum powder (Al), boron powder, and centralite was studied by differential scanning calorimetry (DSC). The results show that TKX-50/HNE possesses good compatibility, TKX-50 and HMX have moderate compatibility, and the compatibility of TKX-50 with TNT, CL-20, centralite, NC, AP, Al, and GAP is poor; in addition, TKX-50/RDX, TKX-50/NC + NG, TKX-50/B, and TKX-50/HTPB have poor compatibility.     

Detection of TNT and its metabolites in body fluids of laboratory animals and in occupational exposed humans

Metabolites of 2,4,6-trinitrotoluene (TNT) were found in the urine of rats and in the blood of rabbits fed with TNT, in the urine of rats exposed to TNT by skin absorption, and in the urine of TNT munition workers. Urine and blood extracts were analyzed by liquid-chromatography/mass spectrometry (LC/MS), The metabolites found included untransformed TNT, 2-amino-4,6-dinitrotoluene (2-A), 4-amino-2,6-dinitrotoluene (4-A), 2,4-diamino-6-nitro-toluene (2-4-DA) and 2,6-diamino-4-nitrotoluene (2,6-DA).     

Thermokinetic decomposition and sensitivity studies of 4,4ˊ-diamino-3,3ˊ-azoxy furazan (DAAF)-based melt cast explosive formulations

4,4ˊ-diamino-3,3ˊ-azoxy furazan (DAAF) is an insensitive high explosive. DAAF has safety characteristics (impact, friction) similar to triaminotrinitrobenzene and shock sensitivity similar to HMX. The present article describes the thermal analysis and sensitivity study of DAAF with RDX and 2,4,6-trinitrotoluene (TNT). DAAF has been evaluated as a possible replacement for RDX in TNT-based, aluminized as well as nonaluminized melt cast formulation. DAAF-based melt cast formulations were characterized for their sensitivity to mechanical stimuli, bomb calorimetric analysis, and thermal decomposition behavior. The thermal analysis reveals the compatibility of DAAF with benchmark explosives like RDX and TNT in explosive formulations. The composition DT (DAAF + TNT) and DTA (DAAF + TNT+ Al) is more friction and impact insensitive as compared to RT (RDX + TNT) and RTA (RDX + TNT+ Al) compositions. The bomb calorimetric values of DT composition as well as DTA composition are higher than RT and RTA compositions. The result shows that DAAF can be effectively used as a RDX replacement in melt cast explosive formulations. DT-based aluminized composition showed more thermal stability than RT- and RTA-based control compositions, which clearly revealed the usefulness of DAAF for enhanced blast effect.     

Application of Liquid Paraffin in Castable CL-20-Based PBX

Hydroxy-terminated polybutadiene (HTPB)/CL-20 castable explosives plasticized with liquid paraffin were processed successfully by a cast-curing method. The compatibility of liquid paraffin with CL-20, influence of liquid paraffin on CL-20 phase transition, and viscosity of the cast mixture were tested and analyzed. The thermal decomposition characteristics, thermal stability, mechanical sensitivity, and velocity of detonation (VOD) of the HTPB/CL-20 plastic-bonded explosives (PBXs) were also measured. The experimental results showed that liquid paraffin was well compatible with CL-20, and it did not have a distinct effect on the ?- to γ-phase transition of CL-20. In addition, the casting mixture was free-flowing with sufficiently low viscosity. When the content of CL-20 is 90% by weight, the measured VOD reached 8,775 m/s (density of 1.78 g/cm³), and the PBXs exhibited moderate mechanical sensitivity and good thermal stability.     

NTO-Picryl Constitutional Isomers—A DFT Study

The quantum chemical properties and the detonation performance of some new explosives, 5-nitro-4-picryl-2,4-dihydro-3H-1,2,4-triazol-3-one (class A) and 5-nitro-2-picryl-2,4-dihydro-3H-1,2,4-triazol-3-one (class B), and their constitutional isomers have been investigated theoretically using the density functional theory (DFT) 6-31G(d,p) method.

All of the constitutional isomers were found to be more sensitive than 5-nitro-2,4-dihydro-3H-1,2,4-triazol-3-one (NTO) and TNT but more insensitive than RDX and HMX. Their detonation performance is higher than that of NTO and TNT and all except two had lower detonation performance than RDX and HMX.     

1-methyl-2,4,5-trinitroimidazole (MTNI), a melt-cast explosive: synthesis and studies on thermal behavior in presence of explosive ingredients

ABSTRACT

Traditionally, TNT based melt-castable explosives have been used till date. Recently, energetics communities are looking for an alternate to TNT in melt-cast formulation because of its toxicity and environmental concerns. 1-Methyl-2,4,5-trinitroimidazole (MTNI) is an insensitive high energy material and potential for use as a melt-cast high explosive formulations in place of TNT. MTNI has superior explosive performance as compared to that of TNT. Typically MTNI is synthesized starting from imidazole by step-wise nitration using strong nitric acid mixture followed by N-methylation offers poor yield. The key step involves during synthesis of MTNI is substitution of third nitro group at fifth position of 2,4-dinitroimidaziole which is limiting for its large-scale preparation. We report herein, an improved method for synthesis of MTNI from 1-methyl-2,4-Dinitroimidazole (MDNI) under different nitration conditions in good yield. Heteropoly acid (HPA) is an efficient, mild and green catalysts used as nitric acid activator. The synthesized MTNI by this method was characterized by FT-IR, NMR & elemental analysis. Thermal behavior of MTNI was determined by differential scanning calorimeter (DSC), thermogravimetric analysis (TGA) and ignition temperature tester. Further, the effects of thermal energy on decomposition of formulations containing MTNI with solid high explosives such as RDX & CL-20 or polymeric binders like HTPB & GAP were investigated. Thermal decomposition mechanisms of MTNI and its precursor, MDNI based on Pyrolysis-GC/MS analysis were also described.     

Oxalylhydrazinium Nitrate and Dinitrate—Efficiency Meets Performance

Oxalylhydrazinium nitrate (OHN) and dinitrate (OHDN) were synthesized by protonation of oxalyldihydrazide with nitric acid. The synthesis is extremely cost effective (～$40/kg at the lab scale) and can be carried out in large scales and very good yields. OHN and OHDN were intensively characterized by low-temperature X-ray diffraction (XRD), nuclear magnetic resonance (NMR) and vibrational spectroscopy. These new organic nitrate salts could be used as powerful ingredients in energetic formulations due to their low sensitivities (measured by Bundesanstalt für Materialforschung und Pröfung methods). Their thermal stability was investigated by differential scanning calorimetry (DSC) measurements. Further thermal studies of OHN showed compatibility with TNT (2,4,6-trinitrotoluene), DNAN (2,4-dinitroanisole), and RDX (1,3,5-trinitro-1,3,5-triazinane). The theoretical detonation and propulsion parameters of OHN and OHDN were calculated with the EXPLO5.5 code and compared to well-known insensitive explosives. The aquatic toxicity of OHN was determined by the luminescent bacteria inhibition test, yielding a much lower toxicity than RDX.     

Comparison of New and Legacy TATBs

Two newly synthesized versions of the insensitive high explosive (IHE) 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) were compared to two legacy explosives currently used by the Department of Energy. Except for thermal analysis, small-scale safety tests could not distinguish between the different synthetic routes. Morphologies of new TATBs were less faceted and more spherical. The particle size distribution of one new material was similar to legacy TATBs, but the other was very fine. Densities and submicron structure of the new TATBs were also significantly different from the legacy explosives and the densities of pressed pellets were lower. Recrystallization of both new TATBs from sulfolane produced nearly hexagonal platelets with improved density and thermal stability.     

Shock initiation of TATB/FEFO formulations

Abstract

The shock initiation properties of transferable insensitive explosive (TIE) formulations based on the solid high explosive, triaminotrinitrobenzene (TATB), and the liquid explosive, bis(2-fluoro-2,2-dinitroethyl) formal (FEFO), are measured by wedge test, embedded particle velocity gauge and embedded manganin pressure gauge techniques and calculated using the Ignition and Growth reactive flow model. These extrudable formulations are demonstrated to be slightly more shock sensitive than the TATB/inert binder explosive, LX-17. However, the TIE formulations are much less sensitive than HMX-based explosives and still qualify as insensitive explosives in safety and hazard tests. The wedge tests showed a very steep dependence of run distance to detonation on the input shock pressure. Embedded gauge and reactive flow modeling results imply that shock initiation begins when a small amount of the solid TATB decomposes rapidly enough to heat the surrounding FEFO to decomposition temperature. The FEFO then reacts rapidly, raising the pressure and temperature sufficiently to cause surface decomposition of the TATB particles at rates comparable to those measured in other TATB-based explosives. An Ignition and Growth reactive flow model for TIE based on these assumptions yields reasonable agreement with the experimental shock initiation data.     

3,5-二叔丁基-4-羟基苄基甲醚的合成及表征

以2,6-二叔丁基酚和多聚甲醛为主要原料,二乙胺为催化剂,在甲醇中加热反应生成了3,5-二叔丁基- 4-羟基苄基甲醚。研究了催化剂的种类和加入量、反应物料配比、反应温度、反应时间、结晶温度等对产物收率的影响。结果表明,以150 g 2,6-二叔丁基苯酚为基准,催化剂用量为2,6-二叔丁基苯酚质量的5%,聚甲醛30 g,甲醇550 mL,反应温度130℃,反应时间6 h,收率达到90%,纯度为97%,用甲醇重结晶后纯度达到99.5%以上。通过FT-IR、~1H NMR和HPLC对其结构进行了表征。     

Analytical Methods for Detonation Residues of Insensitive Munitions

Analytical methods are described for the analysis of post-detonation residues from insensitive munitions. Standard methods were verified or modified to obtain the mass of residues deposited per round. In addition, a rapid chromatographic separation was developed and used to measure the mass of NTO (3-nitro-1,2,4-triazol-5-one), NQ (nitroguanidine) and DNAN (2,4-dinitroanisole). The HILIC (hydrophilic-interaction chromatography) separation described here uses a trifunctionally-bonded amide phase to retain the polar analytes. The eluent is 75/25 v/v acetonitrile/water acidified with acetic acid, which is also suitable for LC/MS applications. Analytical runtime was three minutes. Solid phase extraction and LC/MS conditions are also described.     

A comparative study of performance between TKX-50-based composite explosives and other composite explosives

Dihydroxylammonium 5,5′-bistetrazole-1,1′-diolate (TKX-50) is a promising candidate for high-energy explosive (e.g. HMX), which can be used as the main component in composite explosive formulations processed through a melting method. In the present study, TKX-50-based explosive composites were prepared using 2,4,6-Trinitrotoluene (TNT) or TNT/wax as the carrier, and were compared with HMX-, 3-nitro-1,2,4-triazol-5-one (NTO)-, and hexahydro-1,3,5-trinitro-1,3,5-s-triazine (RDX)-based formulations. Crystal stability, surface micro-topography, thermal decomposition performance, mechanical property, thermal sensitivity, and mechanical sensitivity of the composites were comprehensively investigated. Overall, TKX-50-based formulations exhibited improved properties with a superior safety performance compared to HMX- and RDX-based formulations and better mechanical properties than NTO-based formulations.     

Characterization and Thermal Decomposition of Nanometer 2,2′, 4,4′, 6,6′-Hexanitro-Stilbene and 1,3,5-Triamino-2,4,6-Trinitrobenzene Fabricated by a Mechanical Milling Method

Nanometer 2,2?, 4,4?, 6,6?-hexanitro-stilbene (HNS) and 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) were fabricated on a high-energy ball mill. The particle sizes of nano-HNS and nano-TATB were 98.4 and 57.8 nm, respectively. An SEM analysis was employed to image the micron morphology of nano-explosives. The particle size distribution was calculated by measuring the size of 300 particles in SEM images. XRD, IR, and XPS analyses were used to confirm whether the crystal phase, molecule structure, and surface elements were changed by the milling process. Thermal decomposition of nano-HNS and nano-TATB was investigated by differential scanning calorimetry (DSC) and thermal-infrared spectrometry online (DSC-IR) analyses. Using DSC traces collected from different heating rates, the kinetic and thermodynamic parameters of thermolysis of raw and nano-explosives were calculated (activation energy (E_K), pre-exponential factor (lnA_K), rate constant (k), activation heat (ΔH^≠), activation free energy (ΔG^≠), activation entropy (ΔS^≠), critical temperature of thermal explosion (T_b), and critical heating rate of thermal explosion (dT/dt)_Tb). The results indicated that nano-explosives were of different kinetic and thermodynamic properties from starting explosives. In addition, the gas products for thermal decomposition of nano-HNS and nano-TATB were detected. Although HNS and TATB are both nitro explosives, the decomposition products of the two were different. A mechanism to explain the difference is proposed.     

GAP/CL-20-Based Compound Explosive: A New Booster Formulation Used in a Small-Sized Initiation Network

With ε-2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) and glycidyl azide polymer (GAP) as the solid filler and binder, respectively, GAP/CL-20-based compound explosives were designed and prepared. Using micro injection charge technology, the compound explosives were packed into small grooves to explore their application in a small-sized initiation network. The detonation reliability, detonation velocity, mechanical sensitivity, shock sensitivity, and brisance of the explosive were measured and analyzed. The results show that when the solid content of CL-20 is 82 wt%, the explosive charged in the groove has a smooth surface from a macroscopic view. From a microscopic view, a coarse surface is bonded with many CL-20 particles by GAP binder. The GAP/CL-20-based explosive charge successfully generates detonation waves in a groove larger than 0.6 mm × 0.6 mm. When the charge density in the groove is 1.68 g·cm^?3 (90% theoretical maximum density), the detonation velocity reaches 7,290 m·s^?1. Moreover, this kind of explosive is characterized by low impact and shock sensitivity.     

Thermal initiation of high explosives by electron beam heating

A 40-MeV electron beam has been used to uniformly heat confined samples of high explosives until explosion occurs. From observations of temperature vs time, values were obtained for the thermal initiation thresholds (deposited energy per gram until explosion) and explosion temperatures. These are good indicators of thermal explosion sensitivity. In many cases, the specific heat or the latent heat of fusion were obtained. Data were obtained on the following materials: HMX, PBX-9404, RDX, HBX-1, Comp. A-3, PBXW-109, TATB, TNT, ONP, DIPAM, NDAC, TNB and TNBA. Thermal threshold values vary from 57 cal/gm to 168 cal/gm for these materials. There is some indication that these results are correlated with data from impact sensitivity tests. Radiationinduced decmposition is shown to be very small.     

Characterization and Identification of Explosives and Explosive Residues Using GC-MS,an FTIR Microscope,and HPTLC

ABSTRACT

Characterization and identification of explosives and explosive residues collected from different places in India were made using TLC, GC/EI-MS, and GC-FTIR. The explosives used were NG, PETN, TNT, tetryl, RDX, and NH₄NO₃+fuel oil. Quantitative estimation was made using HPTLC. Mass spectra of the samples using selective ion monitoring (SIM) mode based on the relative intensities of the signals X, X + 1 (intensity of the largest fragment X of the explosive, say, RDX [X = 205] was assumed to be 100%, i.e., X = 100%) show no isotopic substitution. The results were confirmed by FTIR spectra. Some physico-chemical aspects of the explosives are discussed.     

Quantum-Chemical Studies on TATB Processes

Quantum chemical studies have gained paramount importance in screening of thermodynamically feasible chemical processes. The current investigation attempts to select an appropriate process for the synthesis of 1,3,5-triamino-2,4,6-trinitro benzene (TATB), a reasonably powerful insensitive high explosive (IHE) through density functional theory (DFT) calculations. Although, 1,3,5-trichlorobenzene (TCB) and 1,3,5-trihydroxybenzene (THB) routes for synthesis of TATB have been well established, this article demonstrates the predictive capability of thermochemical computations for the identification of a viable process. Thermochemical parameters of reaction species have been obtained from DFT B3LYP/6-31G? calculations and feasibility of the process has been worked out on the basis of free energies of reactions and equilibrium constant as derived from standard enthalpy and entropy of the reaction species. The detailed computational studies have revealed that the THB route is thermodynamically feasible and the same has been supported experimentally.