Coupling effect of high temperature and pressure on the decomposition mechanism of crystalline HMX
The coupling effect of temperature and pressure plays a significant role in the behavior of energetic materials. Energetic materials present extremely complex behavior at high temperatures. Handling difficulties and safety risks have restricted detailed experimental studies on their decomposition me...
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| Format: | Article |
| Language: | English |
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KeAi Communications Co. Ltd.
2020-09-01
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| Series: | Energetic Materials Frontiers |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2666647220300130 |
| _version_ | 1797936418590294016 |
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| author | Xiaowei Wu Zhichao Liu Weihua Zhu |
| author_facet | Xiaowei Wu Zhichao Liu Weihua Zhu |
| author_sort | Xiaowei Wu |
| collection | DOAJ |
| description | The coupling effect of temperature and pressure plays a significant role in the behavior of energetic materials. Energetic materials present extremely complex behavior at high temperatures. Handling difficulties and safety risks have restricted detailed experimental studies on their decomposition mechanisms, especially for less-stable configurations of energetic materials. This has necessitated theoretical studies particularly under the coupling effect. A combinational strategy based on density functional tight-binding molecular dynamics (DFTB-MD) simulations and the density functional theory (DFT) was applied to study the effects of temperature and pressure on the initial decomposition and reaction activation barrier of α-octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) and δ-HMX. A comprehensive analysis of HMX in each system indicated that while the initial decomposition mechanism was not dependent on pressure at high temperatures, the initial reaction rate and activation barrier were highly dependent on pressure. The initial decomposition mechanisms of α-HMX at 1500 K and δ-HMX at 1200 K under pressures of 1–3 GPa involved unimolecular C–H bond breakage and N–NO2 homolysis, respectively. Pressure inhibited the decomposition of α-HMX, but accelerated that of δ-HMX. The decompositions of α-HMX and δ-HMX occurred via first-order reactions. The classical Arrhenius form indicated that pressure (1–3 GPa) increased and decreased the decomposition barriers of α-HMX at 1500 K and δ-HMX at 1200 K, respectively. These findings provide a new understanding of the thermal decomposition and reaction mechanisms of HMX under the coupling effect of temperature and varying pressures. |
| first_indexed | 2024-04-10T18:29:24Z |
| format | Article |
| id | doaj.art-fa98b457946a419fb88516164514cae0 |
| institution | Directory Open Access Journal |
| issn | 2666-6472 |
| language | English |
| last_indexed | 2024-04-10T18:29:24Z |
| publishDate | 2020-09-01 |
| publisher | KeAi Communications Co. Ltd. |
| record_format | Article |
| series | Energetic Materials Frontiers |
| spelling | doaj.art-fa98b457946a419fb88516164514cae02023-02-02T04:49:57ZengKeAi Communications Co. Ltd.Energetic Materials Frontiers2666-64722020-09-01129094Coupling effect of high temperature and pressure on the decomposition mechanism of crystalline HMXXiaowei Wu0Zhichao Liu1Weihua Zhu2Institute for Computation in Molecular and Materials Science and Department of Chemistry, Nanjing University of Science and Technology, Nanjing, 210094, ChinaInstitute for Computation in Molecular and Materials Science and Department of Chemistry, Nanjing University of Science and Technology, Nanjing, 210094, ChinaCorresponding author.; Institute for Computation in Molecular and Materials Science and Department of Chemistry, Nanjing University of Science and Technology, Nanjing, 210094, ChinaThe coupling effect of temperature and pressure plays a significant role in the behavior of energetic materials. Energetic materials present extremely complex behavior at high temperatures. Handling difficulties and safety risks have restricted detailed experimental studies on their decomposition mechanisms, especially for less-stable configurations of energetic materials. This has necessitated theoretical studies particularly under the coupling effect. A combinational strategy based on density functional tight-binding molecular dynamics (DFTB-MD) simulations and the density functional theory (DFT) was applied to study the effects of temperature and pressure on the initial decomposition and reaction activation barrier of α-octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) and δ-HMX. A comprehensive analysis of HMX in each system indicated that while the initial decomposition mechanism was not dependent on pressure at high temperatures, the initial reaction rate and activation barrier were highly dependent on pressure. The initial decomposition mechanisms of α-HMX at 1500 K and δ-HMX at 1200 K under pressures of 1–3 GPa involved unimolecular C–H bond breakage and N–NO2 homolysis, respectively. Pressure inhibited the decomposition of α-HMX, but accelerated that of δ-HMX. The decompositions of α-HMX and δ-HMX occurred via first-order reactions. The classical Arrhenius form indicated that pressure (1–3 GPa) increased and decreased the decomposition barriers of α-HMX at 1500 K and δ-HMX at 1200 K, respectively. These findings provide a new understanding of the thermal decomposition and reaction mechanisms of HMX under the coupling effect of temperature and varying pressures.http://www.sciencedirect.com/science/article/pii/S2666647220300130Coupling effectsInitial decomposition mechanismActivation barriersDensity functional tight-bindingMolecular dynamics |
| spellingShingle | Xiaowei Wu Zhichao Liu Weihua Zhu Coupling effect of high temperature and pressure on the decomposition mechanism of crystalline HMX Energetic Materials Frontiers Coupling effects Initial decomposition mechanism Activation barriers Density functional tight-binding Molecular dynamics |
| title | Coupling effect of high temperature and pressure on the decomposition mechanism of crystalline HMX |
| title_full | Coupling effect of high temperature and pressure on the decomposition mechanism of crystalline HMX |
| title_fullStr | Coupling effect of high temperature and pressure on the decomposition mechanism of crystalline HMX |
| title_full_unstemmed | Coupling effect of high temperature and pressure on the decomposition mechanism of crystalline HMX |
| title_short | Coupling effect of high temperature and pressure on the decomposition mechanism of crystalline HMX |
| title_sort | coupling effect of high temperature and pressure on the decomposition mechanism of crystalline hmx |
| topic | Coupling effects Initial decomposition mechanism Activation barriers Density functional tight-binding Molecular dynamics |
| url | http://www.sciencedirect.com/science/article/pii/S2666647220300130 |
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