Coupling effect of high temperature and pressure on the decomposition mechanism of crystalline HMX

Wu, Xiaowei; Liu, Zhichao; Zhu, Weihua

doi:10.1016/j.enmf.2020.08.003

Cited by 11 publications

(6 citation statements)

References 35 publications

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“…The decay of α-RDX was found to enhance with increasing pressure, implying an intermolecular reaction mechanism; while, that of β-RDX (actually, it should be ε-RDX) decreases, as a unimolecular one. The decomposition mechanism of ε- and γ-RDX under HTHP conditions was reported by Dreger and co-workers. , In contrast to α-RDX, pressure restricts their decomposition, ascribed to that, pressure inhibits bond homolysis. , For another nitroamino-explosive, 1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), its thermal decay is also pressure and polymorph dependent. , In a range of ambient pressure to 0.1 GPa, pressure accelerates the decomposition of δ-HMX; while, it decelerates that of β-HMX at higher pressures from 1 to 3.6 GPa …”

Section: Introductionmentioning

confidence: 88%

“…15,16 For another nitroamino-explosive, 1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), its thermal decay is also pressure and polymorph dependent. 23,24 In a range of ambient pressure to 0.1 GPa, pressure accelerates the decomposition of δ-HMX; while, it decelerates that of β-HMX at higher pressures from 1 to 3.6 GPa. 23 As experimental studies progress toward exploring the thermal decomposition of EMs under high pressure, a detailed knowledge of the atomic/molecular-scale decomposition mechanism becomes increasingly important for understanding the observed phenomena.…”

Section: Introductionmentioning

confidence: 99%

“…It has been reported that the thermal decomposition mechanism of some EMs is pressure dependent. ,,,− Fourier transform infrared (FTIR) spectroscopy in conjunction with a high-pressure diamond anvil cell has been used to determine the effect of pressure on the thermal decomposition kinetics of RDX . The decay of α-RDX was found to enhance with increasing pressure, implying an intermolecular reaction mechanism; while, that of β-RDX (actually, it should be ε-RDX) decreases, as a unimolecular one.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Pressure and Polymorph Dependent Thermal Decomposition Mechanism of Molecular Materials: A Case of 1,3,5,-Trinitro-1,3,5,-triazine

2022

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1,3,5,-Trinitro-1,3,5,-triazine (RDX) serves as an important energetic material and is widely used as various solid propellants and explosives. Understanding the thermal decomposition behaviors of various polymorphs of RDX at high pressure and high temperature is significantly important for safe storage and handling. The present work reveals the early thermal decay mechanisms of two polymorphs (α- and ε-forms) of RDX at high pressure and high temperature by ReaxFF reactive molecular dynamic simulations and climbing image nudged elastic band (CI-NEB) static calculations. It is found that the thermal decomposition rate has positive and negative effects on the pressure for α- and ε-RDX, respectively. This difference originates from the difference of pressure effect on the intermolecular H transfer of the two polymorphs, as we confirm that the bimolecular H transfer rather than the NO2 partition initiates the decay with a significantly lower energy barrier therein. This finding may be beneficial to understand the pressure and polymorph dependent effect on the decay of RDX and to develop a kinetic model for the combustion of solid RDX.

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Section: Introductionmentioning

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Pressure and Polymorph Dependent Thermal Decomposition Mechanism of Molecular Materials: A Case of 1,3,5,-Trinitro-1,3,5,-triazine

2022

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“…Reactivity is the key property for energetic crystals, which is highly related to the detonation and sensitivity of EMs. Theoretical methods—including Reactive FFs [ 97 , 98 , 99 , 100 ], AIMD [ 101 , 102 , 103 , 104 , 105 , 106 , 107 ], and DFTB-MD [ 108 , 109 , 110 , 111 , 112 , 113 , 114 ]—were utilized to reveal reaction mechanism of energetic crystals, and ReaxFF is the most efficient. The reactive FF is a unique type of molecular FF, which can describe not only the interactions between particles and their movements, but also the chemical bond formation and rapture, namely chemical reactions, in the process.…”

Section: Reactive Forcefields and The Applications For Emsmentioning

confidence: 99%

Molecular Forcefield Methods for Describing Energetic Molecular Crystals: A Review

et al. 2022

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Energetic molecular crystals are widely applied for military and civilian purposes, and molecular forcefields (FF) are indispensable for treating the microscopic issues therein. This article reviews the three types of molecular FFs that are applied widely for describing energetic crystals— classic FFs, consistent FFs, and reactive FFs (ReaxFF). The basic principle of each type of FF is briefed and compared, with the application introduced, predicting polymorph, morphology, thermodynamics, vibration spectra, thermal property, mechanics, and reactivity. Finally, the advantages and disadvantages of these FFs are summarized, and some directions of future development are suggested.

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“…In the past two decades, ab initio molecular dynamics (AIMD) simulations were performed to investigate the initial decomposition pathways of HMX 12 , CL-20 13 , and NTO 14 molecules. However, these works were limited to a small system (i.e., <300 atoms), and a short reaction time (i.e., <50 ps).…”

Section: Introductionmentioning

confidence: 99%

Revealing the thermal decomposition mechanism of RDX crystal by a neural network potential

Chu

Chang

Ma³

et al. 2022

Preprint

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A neural network potential (NNP) is developed to investigate the complex reaction dynamics of RDX thermal decomposition. Our NNP model is proven to possess good computational efficiency and retain the ab initio accuracy, which allows the investigation of the entire decomposition process of bulk RDX crystal from an atomic perspective. A series of molecular dynamics (MD) simulations are performed on the NNP to calculate the physical and chemical properties of the RDX crystal. The results show that the NNP can accurately describe the physical properties of RDX crystal, like cell parameters and equation of state. The simulations of RDX thermal decomposition reveal that the NNP could capture the evolution of species at the ab initio accuracy. The complex reaction network was established, and a reaction mechanism of RDX decomposition was provided. The N-N homolysis is the dominant channel, which cannot be observed in previous DFT studies of gas RDX. In addition, the H abstraction reaction by NO2 is found to be the critical pathway for NO and H2O formation, while the HONO elimination is relatively weak. The NNP gives an atomic insight into the complex reaction dynamics of RDX and can be extended to investigate the reaction mechanism of novel energetic materials.

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Coupling effect of high temperature and pressure on the decomposition mechanism of crystalline HMX

Cited by 11 publications

References 35 publications

Pressure and Polymorph Dependent Thermal Decomposition Mechanism of Molecular Materials: A Case of 1,3,5,-Trinitro-1,3,5,-triazine

Pressure and Polymorph Dependent Thermal Decomposition Mechanism of Molecular Materials: A Case of 1,3,5,-Trinitro-1,3,5,-triazine

Molecular Forcefield Methods for Describing Energetic Molecular Crystals: A Review

Revealing the thermal decomposition mechanism of RDX crystal by a neural network potential

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