Type Of Energetic Material Research Articles

Solid-State Polymerization of CO2 from Catalytic Photoexcitation: An Ab Initio Molecular Dynamics Study

Extended form of CO2 (X-CO2) with fully sp3 hybridized C atoms bonded with O atoms is a novel type of energetic material. However, the synthesis requires formidably high temperature and high pressure for commercial production. We propose an alternate approach to produce X-CO2 by photoexcitation of molecular CO2 and through ab initio molecular dynamics simulations demonstrate the formation of a similar polymeric solids at considerably lower pressure and temperature. This polymeric X-CO2 phase can be recovered under ambient pressure with an estimated energy density of 8.63 kJ/g.

Nitrogen-Rich Energetic Salts: Both Cations and Anions Contain Tetrazole Rings

Nitrogen-rich compounds are a kind of new type of energetic material and have good application prospects. They generally have high densities, high positive heats of formation, good thermal stability, and a series of excellent properties. Nitro-rich energetic salts in which cations and anions contain tetrazole rings possess more N-N and C-N bonds. These can help the salts achieve better performance. Their distinct advantages make them attractive for applications in gas generators and high-energy-density materials and as propellant additives.

Cocrystallization of photosensitive energetic copper(II) perchlorate complexes with the nitrogen-rich ligand 1,2-Di(1H-tetrazol-5-yl)ethane.

Two recently introduced concepts in the design of new energetic materials, namely complexation and cocrystallization, have been applied in the synthesis and characterization of the energetic copper(II) compound "[Cu(dt-5-e)2(H2O)](ClO4)2," which consists of two different complex cations and can be described as a model energetic ionic cocrystal. The presence of both the N-rich 1,2-di(1H-tetrazol-5-yl)ethane ligand and oxidizing perchlorate counterion results in a new type of energetic material. The ionic complex cocrystal consists of a mononuclear and a trinuclear complex unit. It can be obtained by precipitation from perchloric acid or by dehydration of the related mononuclear coordination compound [Cu(dt-5-e)2(H2O)2](ClO4)2·2H2O at 70 °C in the solid state. The transformation starting at 60 °C was monitored by X-ray powder diffraction and thermal analysis. The energetic ionic cocrystal was shown to be a new primary explosive suitable for laser ignition. The different coordination spheres within the ionic cocrystal (octahedral and square pyramidal) were shown by UV/vis/NIR spectroscopy to result in excellent light absorption.

총탄 충격이 가해진 반응 시스템의 파괴 거동에 관한 수치적 연구

무기체계 개발에서 예상치 못한 고속의 총탄 충격을 받았을 때 반응 시스템의 폭발 반응을 예측하는 것은 안정성 확보를 위하여 매우 중요하다. 본 연구에서는 LX-17(92.5% TATB, 7.5% Kel-F)과 AP기반의 고체 추진제(88% AP, 12% HTPB)가 충전된 반응 시스템에 한계 속도로 충돌하는 총탄 충격을 가했을 경우 발생하는 폭굉 현상 및 파괴 거동을 I&G 모델이 적용된 2차원 하이드로 수치해석을 통해 규명하고자 하였다. 해석 결과, LX-17의 경우 충격-폭굉 천이 현상(SDT)이 주요한 메커니즘으로 작용한 반면 고체 추진제는 상대적으로 안정한 모습을 보였다. 즉, 시스템의 파괴는 내부 압력의 급격한 증가와 격렬한 화학반응을 동반하는 고에너지 물질의 폭굉 현상이 그 원인이며, 폭발등급이 낮은 경우에는 고속 충돌에도 발화되지 않아 커버가 완전 파쇄에 이르지 않는 것으로 관찰되었다.

Quantum Chemistry Derived Criteria for Impact Sensitivity

AbstractEnergetic materials are a special and important kind of substance. Impact sensitivity, which refers to the vulnerability to explosion under external stimuli, measures the safety and reliability of an energetic material and is a critical property. Various efforts have been made to rationalize the impact sensitivity of different types of energetic materials. Since a chemical explosion is a chemical reaction dominated phenomenon, a comprehensive understanding of such explosive processes requires detailed information of chemical bonding and molecular interaction. Quantum chemistry provides a modern theory of chemical bonding and computational quantum chemistry is a powerful tool to investigate chemical phenomena. Even at the very beginning of computational quantum chemistry, researchers in the field of energetic materials have begun to apply quantum chemistry to explosive properties. In this paper we review the quantum chemistry studies on impact sensitivity and examine various quantum chemistry derived parameters used to rationalize the impact sensitivity ordering of various energetic materials.

Study on the Stability of a New Propellant

GLQ propellant is a new type of energetic material, extensive research indicates that the traditional methods evaluating the stability of this propellant are unsuitable. So in this article, the stability of this material was studied by aging test, methyl-violet test and gas phase chromatography test. The results show that gas phase chromatography test is feasible for evaluating the stability of this material, but methyl-violet test is unsuitable.

An improved simple method for prediction of entropy of fusion of energetic compounds

A new general method has been introduced for prediction of entropy of fusion of important classes of energetic compounds including polynitro arene, acyclic and cyclic nitramine, nitrate ester and nitroaliphatic compounds. It extends earlier work, which was restricted to nitroaromatic compounds, to estimate entropy of fusions of any compound containing at least one of the groups ArNO2, CNO2, CONO2 or NNO2 through additive and correcting non-additive functions. The number of nitrogen and oxygen atoms in an energetic compound was used as additive function. For 92 compounds (corresponding to 167 measured values) belong to different types of energetic materials, the root-mean square (rms) deviation of the additive part is 13.5J/(Kmol). The reliability of the new model can be increased by considering one correcting non-additive function for which the value of rms deviation is 10.2J/(Kmol). The predicted outcomes of the new method, by using only additive part or both additive and non-additive functions, give more reliable results as compared to one of the best available methods.

Kinetic Compensation Effect of Kinetic Parameters of Thermal Explosion Test

The kinetic parameters of thermal explosion tests with five-second delay for 273 energetic materials were analyzed. The compensation effect exists between the two thermal explosion kinetic parameters of these energetic materials, e.g. lnA and Eb. The kinetic parameters of these energetic materials can be expressed by a single linear regression equation for the single compound or mixture under all conditions. The slopes of the regression equation for various systems are in the range from 0.1952 to 0.2413 (mol•kJ-1). The regression equation for single compound or mixture with one type of energetic material as main component has better linearity. Therefore, their “iso-kinetic temperature” Tik is close to their thermal explosion temperature Tb and the “iso-kinetic delay period”τik is also close to the 5 seconds.

Study on the Methods Evaluating the Stability of a New Type of Energetic Material

171 propellant is a new type of energetic material, extensive research indicates that the traditional methods evaluating the stability of this propellant are unsuitable. So in this article, the stability of this material was studied by aging test, methyl-violet test and gas phase chromatography test. The results show that gas phase chromatography test is feasible for evaluating the stability of this material, but methyl-violet test is unsuitable.

Stability of Chapman–Jouguet detonations for a stiffened-gas model of condensed-phase explosives

The analysis of the linear stability of a planar Chapman–Jouguet detonation wave is reformulated for an arbitrary caloric (incomplete) equation of state in an attempt to better represent the stability properties of detonations in condensed-phase explosives. Calculations are performed on a ‘stiffened-gas’ equation of state which allows us to prescribe a finite detonation Mach number while simultaneously allowing for a detonation shock pressure that is substantially larger than the ambient pressure. We show that the effect of increasing the ambient sound speed in the material, for a given detonation speed, has a stabilizing effect on the detonation. We also show that the presence of the slow reaction stage, a feature of detonations in certain types of energetic materials, where the detonation structure is characterized by a fast reaction stage behind the detonation shock followed by a slow reaction stage, tends to have a destabilizing effect.

Thermal Decomposition and Combustion of Ammonium Dinitramide (Review)

A comprehensive review of thermal decomposition and combustion of ammonium dinitramide (ADN) has been conducted. The basic thermal properties, chemical pathways, and reaction products in both the condensed and gas phases are analyzed over a broad range of ambient conditions. Detailed combustion-wave structures and burning-rate characteristics are discussed. Prominent features of ADN combustion are identified and compared with other types of energetic materials. In particular, the influence of various condensed- and gas-phase processes in dictating the pressure and temperature sensitivities of the burning rate is examined. In the condensed phase, decomposition proceeds through the mechanisms ADN → NH4NO3 + N2O and ADN → NH3 + HNO3 + N2O, the former mechanism being the basic one. In the gas phase, the mechanisms ADN → NH3 + HDN and ADN → NH3 + HNO3 + N2O are prevalent. The gas-phase combustion-wave structure in the range of 5–20 atm consists of a near-surface primary flame followed by a dark-zone temperature plateau at 600–1000°C and a secondary flame followed by another dark-zone temperature plateau at 1000–1400°C. At higher pressures (60 atm and above), a final flame is observed at about 1800°C without the existence of any dark-zone temperature plateau. ADN combustion is stable in the range of 5–20 atm and the pressure sensitivity of the burning rate has the form r b = 20.72p 0.604 [mm/sec] (p = 0.5–2.0 MPa). The burning characteristics are controlled by exothermic decomposition in the condensed phase. Above 100 atm, the burning rate is well correlated with pressure as r b = 8.50p 0.608 [mm/sec] (p = 10–36 MPa). Combustion is stable, and intensive heat feedback from the gas phase dictates the burning rate. The pressure dependence of the burning rate, however, becomes irregular in the range of 20–100 atm. This phenomenon may be attributed to the competing influence of the condensed-phase and gas-phase exothermic reactions in determining the propellant surface conditions and the associated burning rate.

Computational studies on the infrared vibrational spectra, thermodynamic properties, detonation properties, and pyrolysis mechanism of octanitrocubane

The molecular geometries, infrared vibrational spectra, and thermodynamic properties of octanitrocubane (ONC) are calculated using the density functional theory (DFT) method at the B3LYP/6-31G* level. The IR frequency scaling factor 0.9501 suitable for polynitrocubanes is obtained at the B3LYP/6-31G* level, and the calculated IR frequencies of ONC are scaled. The accurate heat of formation 726.47 kJ/mol of ONC in gas phase is obtained via designed isodesmic reaction in which the cubane cage skeleton has been kept. The sublimation enthalpy, density, and heat of formation for ONC crystal are also calculated, and they are 220.63 kJ/mol, 2.189 g/cm3, and 505.84 kJ/mol, respectively. In addition, the estimated detonation velocity and detonation pressure of ONC are 10.26 mm/ms and 520.86 kbar, respectively. Finally, the pyrolysis mechanism of ONC is studied using various theoretical methods, i.e., MP2, DFT, and selected MINDO/3 semiempirical MO, based on the unrestricted Hartree–Fock model. The calculated results show that the pyrolysis initiation reaction of ONC, i.e., rate-controlling step, is to form a diradical by the single C–C bond breaking in the cube. The second C–C bond breaking is easily followed to form a nitrocyclooctatetraene. The calculated activation energy for the pyrolysis initiation reaction of ONC, obtained from B3LYP/6-31G* method, is 155.30 kJ/mol, which this rather large activation energy indicates that ONC is a new type of energetic material with less sensitivity and better thermal stability, and has highly exploitable values.

99/02681 Synthesis and calculation of properties of N-(difluoroamino) azoles, the novel type of energetic materials

99/02681 Synthesis and calculation of properties of N-(difluoroamino) azoles, the novel type of energetic materials

Synthesis and Calculation of Properties of N-Difluoroaminoazoles, the Novel Type of Energetic Materials

Synthesis and Calculation of Properties of N-Difluoroaminoazoles, the Novel Type of Energetic Materials