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Wen M, Chang X, Xu Y, Chen D, Chu Q. Determining the mechanical and decomposition properties of high energetic materials (α-RDX, β-HMX, and ε-CL-20) using a neural network potential. Phys Chem Chem Phys 2024; 26:9984-9997. [PMID: 38477375 DOI: 10.1039/d4cp00017j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2024]
Abstract
Molecular simulations of high energetic materials (HEMs) are limited by efficiency and accuracy. Recently, neural network potential (NNP) models have achieved molecular simulations of millions of atoms while maintaining the accuracy of density functional theory (DFT) levels. Herein, an NNP model covering typical HEMs containing C, H, N, and O elements is developed. The mechanical and decomposition properties of 1,3,5-trinitroperhydro-1,3,5-triazine (RDX), hexahydro-1,3,5-trinitro-1,3,5-triazine (HMX), and 2,4,6,8,10,12-hexanitrohexaazaisowurtzitane (CL-20) are determined by employing the molecular dynamics (MD) simulations based on the NNP model. The calculated results show that the mechanical properties of α-RDX, β-HMX, and ε-CL-20 agree with previous experiments and theoretical results, including cell parameters, equations of state, and elastic constants. In the thermal decomposition simulations, it is also found that the initial decomposition reactions of the three crystals are N-NO2 homolysis, corresponding radical intermediates formation, and NO2-induced reactions. This decomposition trajectory is mainly divided into two stages separating from the peak of NO2: pyrolysis and oxidation. Overall, the NNP model for C/H/N/O elements in this work is an alternative reactive force field for RDX, HMX, and CL-20 HEMs, and it opens up new potential for future kinetic study of nitramine explosives.
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Affiliation(s)
- Mingjie Wen
- State Key Laboratory of Explosion Science and Safety Protection, Beijing Institute of Technology, Beijing 100081, P. R. China.
| | - Xiaoya Chang
- State Key Laboratory of Explosion Science and Safety Protection, Beijing Institute of Technology, Beijing 100081, P. R. China.
| | - Yabei Xu
- State Key Laboratory of Explosion Science and Safety Protection, Beijing Institute of Technology, Beijing 100081, P. R. China.
| | - Dongping Chen
- State Key Laboratory of Explosion Science and Safety Protection, Beijing Institute of Technology, Beijing 100081, P. R. China.
| | - Qingzhao Chu
- State Key Laboratory of Explosion Science and Safety Protection, Beijing Institute of Technology, Beijing 100081, P. R. China.
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2
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Yang F, Yang Z, Yu Q, Liu Z, Li G, Zhao C, Tian Y. Temperature-dependent decomposition of the CL-20/MTNP cocrystal after phase separation. Phys Chem Chem Phys 2024; 26:8547-8558. [PMID: 38412456 DOI: 10.1039/d3cp06279a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/29/2024]
Abstract
CL-20 (2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane)-based cocrystals are attractive energetic cocrystals with a potential for high energy and low sensitivity, which account for nearly one-third of energetic cocrystals. The applications of cocrystal explosives require in-depth understanding of their thermal kinetics behaviors. Although thermal kinetics of the decomposition of CL-20-based cocrystals having no melting point have been studied, relevant research of CL-20-based cocrystals having a melting point, which are also the most frequently observed type, is still rare. In this study, the CL-20/MTNP (1-methyl-3,4,5-trinitropyrazole) cocrystal was chosen as a typical CL-20-based cocrystal having a melting point to investigate its thermal kinetics behavior. The thermal decomposition of CL-20/MTNP was identified to be a typical heterogeneous reaction with phase separation before decomposition. Due to the presence of intermolecular hydrogen bonds between CL-20 and molten MTNP after phase separation, the thermal decomposition behavior of CL-20/MTNP was strongly temperature-dependent. The complex decomposition reaction was separated into its three constituent pathways to simplify the kinetic analysis. On the basis of in-depth understanding of the decomposition process, the best functions of mechanism and kinetic parameters for each process of CL-20/MTNP decomposition were obtained using the model-fitting method. Finally, important thermal safety indicators, such as TMRad and SADT were simulated by combining the established kinetic models. This study provides further insights into the entire reaction process of the CL-20/MTNP cocrystal and would help in its better applications.
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Affiliation(s)
- Fang Yang
- Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang, Sichuan 621900, China.
| | - Zongwei Yang
- Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang, Sichuan 621900, China.
| | - Qian Yu
- Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang, Sichuan 621900, China.
| | - Zhongping Liu
- Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang, Sichuan 621900, China.
| | - Gang Li
- Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang, Sichuan 621900, China.
| | - Chuande Zhao
- Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang, Sichuan 621900, China.
| | - Yong Tian
- Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang, Sichuan 621900, China.
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3
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Sun Z, Ji J, Zhu W. Effects of Nanoparticle Size on the Thermal Decomposition Mechanisms of 3,5-Diamino-6-hydroxy-2-oxide-4-nitropyrimidone through ReaxFF Large-Scale Molecular Dynamics Simulations. Molecules 2023; 29:56. [PMID: 38202639 PMCID: PMC10779735 DOI: 10.3390/molecules29010056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2023] [Revised: 12/16/2023] [Accepted: 12/17/2023] [Indexed: 01/12/2024] Open
Abstract
ReaxFF-lg molecular dynamics method was employed to simulate the decomposition processes of IHEM-1 nanoparticles at high temperatures. The findings indicate that the initial decomposition paths of the nanoparticles with different sizes at varying temperatures are similar, where the bimolecular polymerization reaction occurred first. Particle size has little effect on the initial decomposition pathway, whereas there are differences in the numbers of the species during the decomposition and their evolution trends. The formation of the hydroxyl radicals is the dominant decomposition mechanism with the highest reaction frequency. The degradation rate of the IHEM-1 molecules gradually increases with the increasing temperature. The IHEM-1 nanoparticles with smaller sizes exhibit greater decomposition rate constants. The activation energies for the decomposition are lower than the reported experimental values of bulk explosives, which suggests a higher sensitivity.
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Affiliation(s)
- Zijian Sun
- Institute for Computation in Molecular and Materials Science, School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China;
| | - Jincheng Ji
- College of Chemical Engineering and Pharmacy, Jingchu University of Technology, Jingmen 448000, China;
| | - Weihua Zhu
- Institute for Computation in Molecular and Materials Science, School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China;
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Wu J, Wu J, Li J, Shang Y, Chen L. Molecular Dynamics Simulations of the Thermal Decomposition of RDX/HTPB Explosives. ACS OMEGA 2023; 8:18851-18862. [PMID: 37273601 PMCID: PMC10233698 DOI: 10.1021/acsomega.3c01160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 04/28/2023] [Indexed: 06/06/2023]
Abstract
The addition of binders to energetic materials is known to complicate the thermal decomposition process of such materials. To assess this effect, the present work studied the thermal decomposition of cyclotrimethylene trinitramine (RDX)/hydroxy-terminated polybutadiene (HTPB) mixtures and of pure RDX over the temperature range of 2000-3500 K by combining the classical reaction and first-principles molecular dynamics methods. The incorporation of HTPB as a binder was found to significantly reduce the decomposition rate of RDX. At 3500 K, the decay rate constant of RDX in the RDX/HTPB system is 2.0141 × 1012 s-1, while it is 2.7723 × 1012 s-1 in the pure RDX system. However, the binder HTPB had little effect on the initial decomposition mechanism, which involved the rupture of N-NO2 bonds to produce NO2. The HTPB was predicted to undergo dehydrogenation and chain breaking. The free H resulting from these processes was predicted to react with low-molecular-weight intermediates generated by the RDX, resulting in greater equilibrium quantities of the final products H2O and H2 being obtained from the mixed system compared with pure RDX. HTPB-chain fragments were also found to combine with the primary RDX decomposition product NO2 to inhibit the formation of N2 and CO2.
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Wang F, Du G, Zhang C, Wang QY. Mechanism of the Impact-Sensitivity Reduction of Energetic CL-20/TNT Cocrystals: A Nonequilibrium Molecular Dynamics Study. Polymers (Basel) 2023; 15:polym15061576. [PMID: 36987360 PMCID: PMC10057516 DOI: 10.3390/polym15061576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 03/07/2023] [Accepted: 03/16/2023] [Indexed: 03/30/2023] Open
Abstract
High-energy low-sensitivity explosives are research objectives in the field of energetic materials, and the formation of cocrystals is an important method to improve the safety of explosives. However, the sensitivity reduction mechanism of cocrystal explosives is still unclear. In this study, CL-20/TNT, CL-20 and TNT crystals were taken as research objects. On the basis of the ReaxFF-lg reactive force field, the propagation process of the wave front in the crystals at different impact velocities was simulated. The molecular dynamics data were used to analyze the molecular structure changes and initial chemical reactions, and to explore the sensitivity reduction mechanism of the CL-20/TNT cocrystal. The results showed that the chemical reaction of the CL-20/TNT cocrystal, compared with the CL-20 single crystal, is different under different impact velocities. At an impact velocity of 2 km/s, polymerization and separation of the component molecules weakened the decomposition of CL-20. At an impact velocity of 3 km/s, the decay rates of CL-20 and TNT in the cocrystal decreased, and the intermediate products were enhanced, such as nitrogen oxides. At an impact velocity of 4 km/s, the cocrystal had little effect on the decay rates of the molecules and formation of CO2, but it enhanced formation of N2 and H2O. This may explain the reason for the impact-sensitivity reduction of the CL-20/TNT cocrystal.
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Affiliation(s)
- Fuping Wang
- Department of Chemistry and Material Science, Langfang Normal University, Langfang 065000, China
| | - Guangyan Du
- Department of Chemistry and Material Science, Langfang Normal University, Langfang 065000, China
| | - Chenggen Zhang
- Department of Chemistry and Material Science, Langfang Normal University, Langfang 065000, China
| | - Qian-You Wang
- Henan Key Laboratory of Crystalline Molecular Functional Materials, Green Catalysis Center and College of Chemistry, Zhengzhou University, Zhengzhou 450001, China
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Li S, Chen L, Gui X, He D, Hu J, Huang Z, Lin S, Tu Y, Dong Y. Molecular Dynamics Simulation for Thiolated Poly(ethylene glycol) at Low‐Temperature Based on the Density Functional Tight‐Binding Method. ADVANCED THEORY AND SIMULATIONS 2022. [DOI: 10.1002/adts.202200281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Shi Li
- Guangzhou Institute of Chemistry Chinese Academy of Sciences Guangzhou 510650 P. R. China
- School of Chemical and Environmental Engineering Anhui Polytechnic University Wuhu 241000 P. R. China
- University of Chinese Academy of Sciences Beijing 100049 P. R. China
| | - Lei Chen
- Guangzhou Institute of Chemistry Chinese Academy of Sciences Guangzhou 510650 P. R. China
- University of Chinese Academy of Sciences Beijing 100049 P. R. China
| | - Xuefeng Gui
- Guangzhou Institute of Chemistry Chinese Academy of Sciences Guangzhou 510650 P. R. China
- University of Chinese Academy of Sciences Beijing 100049 P. R. China
- Guangdong Provincial Key Laboratory of Organic Polymer Materials for Electronics Guangzhou 510650 P. R. China
- CAS Engineering Laboratory for Special Fine Chemicals Guangzhou 510650 P. R. China
- Incubator of Nanxiong CAS Co. Ltd. Nanxiong 512400 P. R. China
| | - Daguang He
- Guangzhou Institute of Chemistry Chinese Academy of Sciences Guangzhou 510650 P. R. China
- University of Chinese Academy of Sciences Beijing 100049 P. R. China
| | - Jiwen Hu
- Guangzhou Institute of Chemistry Chinese Academy of Sciences Guangzhou 510650 P. R. China
- University of Chinese Academy of Sciences Beijing 100049 P. R. China
- Guangdong Provincial Key Laboratory of Organic Polymer Materials for Electronics Guangzhou 510650 P. R. China
- CAS Engineering Laboratory for Special Fine Chemicals Guangzhou 510650 P. R. China
- Incubator of Nanxiong CAS Co. Ltd. Nanxiong 512400 P. R. China
| | - Zhenzhu Huang
- Guangzhou Institute of Chemistry Chinese Academy of Sciences Guangzhou 510650 P. R. China
- University of Chinese Academy of Sciences Beijing 100049 P. R. China
- Guangdong Provincial Key Laboratory of Organic Polymer Materials for Electronics Guangzhou 510650 P. R. China
- CAS Engineering Laboratory for Special Fine Chemicals Guangzhou 510650 P. R. China
- Incubator of Nanxiong CAS Co. Ltd. Nanxiong 512400 P. R. China
| | - Shudong Lin
- Guangzhou Institute of Chemistry Chinese Academy of Sciences Guangzhou 510650 P. R. China
- University of Chinese Academy of Sciences Beijing 100049 P. R. China
- Guangdong Provincial Key Laboratory of Organic Polymer Materials for Electronics Guangzhou 510650 P. R. China
- CAS Engineering Laboratory for Special Fine Chemicals Guangzhou 510650 P. R. China
- Incubator of Nanxiong CAS Co. Ltd. Nanxiong 512400 P. R. China
| | - Yuanyuan Tu
- Guangzhou Institute of Chemistry Chinese Academy of Sciences Guangzhou 510650 P. R. China
- University of Chinese Academy of Sciences Beijing 100049 P. R. China
- Guangdong Provincial Key Laboratory of Organic Polymer Materials for Electronics Guangzhou 510650 P. R. China
- CAS Engineering Laboratory for Special Fine Chemicals Guangzhou 510650 P. R. China
- Incubator of Nanxiong CAS Co. Ltd. Nanxiong 512400 P. R. China
| | - Yonglu Dong
- Guangzhou Institute of Chemistry Chinese Academy of Sciences Guangzhou 510650 P. R. China
- Incubator of Nanxiong CAS Co. Ltd. Nanxiong 512400 P. R. China
- Management Committee of Shaoguan NanXiong Hi‐Tech Industry Development Zone Nanxiong 512400 P. R. China
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7
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Beste A. Molecular Inclusion of Small Aging Products into the Hexanitrohexaazaisowurtzitane (CL‐20) Lattice: Part II, Polymorph Dependence. PROPELLANTS EXPLOSIVES PYROTECHNICS 2022. [DOI: 10.1002/prep.202100360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Ariana Beste
- Sandia National Laboratories, New Mexico 1515 Eubank SE Albuquerque 87185 NM
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8
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Zhu S, Yang W, Gan Q, Cheng N, Feng C. Early thermal decay of energetic hydrogen- and nitro-free furoxan compounds: the case of DNTF and BTF. Phys Chem Chem Phys 2021; 24:1520-1531. [PMID: 34935783 DOI: 10.1039/d1cp02881b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Exploration of the initial reactions of H-free and nitro-free energetic materials could enrich our understanding of the thermal decomposition mechanism of various energetic materials (EMs). In this work, two furoxan compounds, 3,4-dinitrofurazanfuroxan (DNTF) and benzotrifuroxan (BTF), were investigated to shed light on the decay mechanism of furoxan compounds based on the combination of self-consistent charge density functional tight binding and molecular dynamics simulations. The results show that DNTF and BTF decay via a unimolecular mechanism, and the transformation of the furoxan ring into a nitro group is suggested as a novel initial channel. Five initial steps of DNTF thermal decomposition are observed, including NO2 loss and the N(O)-O bond cleavage of the central and peripheral rings. The bond cleavage of peripheral rings dominates the decay at low temperatures, while the central ring opening and C-NO2 dissociation govern the high temperature decay. Besides, NO2, CO and NO fragments are mainly yielded at high temperatures, while CO3N2 is dominant at low temperatures. The three-stage characteristic of the exothermic BTF decay is described under programmed heating conditions for the first time. Four initial steps of BTF thermal decomposition were identified, including furoxan ring opening reactions and the breakage of the 6-membered ring C-C bond. The cleavage of the N(O)-O bond is dominant in the initial step of BTF decomposition under different heating conditions, and the frequency increases with increasing temperature. In addition, the amounts of CON, ON and CO are higher at high temperatures, while C2O2N2 shows an opposite trend. The findings of this work provide deep insights into the complicated sensitivity mechanism of EMs.
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Affiliation(s)
- Shuangfei Zhu
- State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing 100081, China.
| | - Wei Yang
- School of Materials Science & Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Qiang Gan
- State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing 100081, China.
| | - Nianshou Cheng
- State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing 100081, China.
| | - Changgen Feng
- State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing 100081, China.
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9
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Zhang J, Guo W. The role of electric field on decomposition of CL-20/HMX cocrystal: A reactive molecular dynamics study. J Comput Chem 2021; 42:2202-2212. [PMID: 34476813 DOI: 10.1002/jcc.26748] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 08/11/2021] [Accepted: 08/18/2021] [Indexed: 11/10/2022]
Abstract
Electric field can initiate decomposition or detonation of explosives, but underlying mechanism is unclear. Here, we performed ReaxFF molecular dynamics simulation for decomposition of a cocrystal, formed by 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) and 1,3,5,7-tetranitro-1,3,5,7-tetrazacyclooctane (HMX), solely induced by electric field. A new analytical method was proposed to obtain detailed decomposition mechanism. Results show that electric fields play important roles in decomposition of CL-20/HMX cocrystal, such as heating the system and causing the explosive to decompose. Strong constant field makes CL-20 molecules in the cocrystal decompose at significantly lower temperature, which greatly increases sensitivity. This is ascribed to the distinct decomposition mechanism that CN bond rupture dominates the initial step of CL-20's decomposition. Contrarily, oscillating field has a stronger heating effect but weaker influence on sensitivity. Moreover, HMX exhibits desensitizing effect in CL-20/HMX cocrystal under electric field. These results enhance our understanding of sensitivity mechanism beyond mechanical stimuli in explosives.
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Affiliation(s)
- Jidong Zhang
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, China.,Key Laboratory of Ecophysics and Department of Physics, College of Science, Shihezi University, Shihezi, China
| | - Wei Guo
- Frontiers Science Center for High Energy Material (MOE), Beijing Institute of Technology, Beijing, China.,School of Physics, Beijing Institute of Technology, Beijing, China
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10
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Zeng L, Li J, Qiao C, Jiang Y, Wu J, Li H, Zhang J. Theoretical studies on new family of bridged difurazan derivatives with excellent heat of formation. J CHIN CHEM SOC-TAIP 2021. [DOI: 10.1002/jccs.202100307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Lian Zeng
- School of Materials Science and Engineering Southwest University of Science and Technology Mianyang P. R. China
| | - Junyan Li
- School of Materials Science and Engineering Southwest University of Science and Technology Mianyang P. R. China
| | - Chen Qiao
- School of Materials Science and Engineering Southwest University of Science and Technology Mianyang P. R. China
| | - Yuhe Jiang
- School of Materials Science and Engineering Southwest University of Science and Technology Mianyang P. R. China
| | - Jinting Wu
- School of Materials Science and Engineering Southwest University of Science and Technology Mianyang P. R. China
- State Key Laboratory of Explosion Science and Technology Beijing Institute of Technology Beijing P. R. China
| | - Hongbo Li
- School of Materials Science and Engineering Southwest University of Science and Technology Mianyang P. R. China
| | - Jianguo Zhang
- State Key Laboratory of Explosion Science and Technology Beijing Institute of Technology Beijing P. R. China
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Xiao Y, Chen L, Yang K, Geng D, Lu J, Wu J. Mechanism of the improvement of the energy of host-guest explosives by incorporation of small guest molecules: HNO 3 and H 2O 2 promoted C-N bond cleavage of the ring of ICM-102. Sci Rep 2021; 11:10559. [PMID: 34006908 PMCID: PMC8131615 DOI: 10.1038/s41598-021-89939-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 05/04/2021] [Indexed: 11/09/2022] Open
Abstract
Host–guest materials exhibit great potential applications as an insensitive high-energy–density explosive and low characteristic signal solid propellant. To investigate the mechanism of the improvement of the energy of host–guest explosives by guest molecules, ReaxFF-lg reactive molecular dynamics simulations were performed to calculate the thermal decomposition reactions of the host–guest explosives systems ICM-102/HNO3, ICM-102/H2O2, and pure ICM-102 under different constant high temperatures and different heating rates. Incorporation of guest molecules significantly increased the energy level of the host–guest system. However, the initial reaction path of the ICM-102 molecule was not changed by the guest molecules. The guest molecules did not initially participate in the host molecule reaction. After a period of time, the H2O2 and HNO3 guest molecules promoted cleavage of the C–N bond of the ICM-102 ring. Stronger oxidation and higher oxygen content resulted in the guest molecules more obviously accelerating destruction of the ICM-102 ring structure. The guest molecules accelerated the initial endothermic reaction of ICM-102, but they played a more important role in the intermediate exothermic reaction stage: incorporation of guest molecules (HNO3 and H2O2) greatly improved the heat release and exothermic reaction rate. Although the energies of the host–guest systems were clearly improved by incorporation of guest molecules, the guest molecules had little effect on the thermal stabilities of the systems.
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Affiliation(s)
- Yiwen Xiao
- State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing, 100081, China
| | - Lang Chen
- State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing, 100081, China.
| | - Kun Yang
- State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing, 100081, China
| | - Deshen Geng
- State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing, 100081, China
| | - Jianying Lu
- State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing, 100081, China
| | - Junying Wu
- State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing, 100081, China
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Han Q, Zhu W. Effect of particle size on the thermal decomposition of nano ε-CL-20 by ReaxFF-lg molecular dynamics simulations. Chem Phys Lett 2020. [DOI: 10.1016/j.cplett.2020.138067] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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13
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Wang F, Chen L, Geng D, Lu J, Wu J. Chemical reactions of a CL-20 crystal under heat and shock determined by ReaxFF reactive molecular dynamics simulations. Phys Chem Chem Phys 2020; 22:23323-23332. [PMID: 33035287 DOI: 10.1039/d0cp02796k] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Studying the chemical reactions of hexanitrohexaazaisowurtzitane (CL-20) under heat and shock is helpful to understand its sensitivity and shock initiation mechanism. In this work, several molecular dynamics simulations were performed under three different conditions: high temperature, high temperature and pressure, and shock. The formation and breakage of chemical bonds, changes of bond lengths, and initial reactions were analysed. It was found that the main small-molecule product of CL-20 during initial decomposition under the three different conditions was always NO2, but the generation pathways were different. At high temperatures, NO2 was generated by the direct cleavage of N-NO2 bonds. In contrast, high pressure and shock promoted the transfer of O atoms to N atoms connected to NO2, leading to the breakage of N-NO2 bonds. Almost all NO2 originated from the transfer of O atoms under the shock conditions.
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Affiliation(s)
- Fuping Wang
- Department of Chemistry and Material Science, Langfang Normal University, Langfang 065000, China
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14
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Jiang J, Qiu-li J, Chen Y, Hao W, Liu Y, Zhang SH. ReaxFF MD simulations of thermolysis mechanism of 2, 6-diamino-3, 5-dinitropyrazine-1-oxidated. COMPUT THEOR CHEM 2020. [DOI: 10.1016/j.comptc.2020.112891] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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15
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Rice BM, Mattson WD, Larentzos JP, Byrd EFC. Heuristics for chemical species identification in dense systems. J Chem Phys 2020; 153:064102. [DOI: 10.1063/5.0015664] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Affiliation(s)
- Betsy M. Rice
- US Army CCDC Army Research Laboratory, Aberdeen Proving Ground, Aberdeen, Maryland 21005, USA
| | - William D. Mattson
- US Army CCDC Army Research Laboratory, Aberdeen Proving Ground, Aberdeen, Maryland 21005, USA
| | - James P. Larentzos
- US Army CCDC Army Research Laboratory, Aberdeen Proving Ground, Aberdeen, Maryland 21005, USA
| | - Edward F. C. Byrd
- US Army CCDC Army Research Laboratory, Aberdeen Proving Ground, Aberdeen, Maryland 21005, USA
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16
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Li Y, Wu J, Yang L, Geng D, Sultan M, Chen L. Polymerization Effects on the Decomposition of a Pyrazolo-Triazine at high Temperatures and Pressures. ChemistryOpen 2020; 9:470-479. [PMID: 32313787 PMCID: PMC7155779 DOI: 10.1002/open.202000006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 03/15/2020] [Indexed: 11/15/2022] Open
Abstract
4-amino-3-aminopyrazole-8-trinitropyrazolo-[5, 1-c] [1, 2, 4]triazine (PTX, C5H2N8O6) has good detonation performance, thermal stability and low mechanical sensitivity, which endow it with good development prospects in insensitive ammunition applications. To study the effects of polymerization on the decomposition of PTX, the reaction processes of PTX at different conditions were simulated by quantum chemistry and molecular dynamics methods. In this paper, the effects of polymerization on the decomposition of PTX were studied in terms of species information, reaction path of PTX, bond formation and bond cleavage, evolution of small molecules and clusters, and kinetic parameters at different stages. The results show that under the high-temperature and high-pressure conditions, the initial reaction path of unimolecular PTX in the thermal decomposition is mainly the cleavage of C-NO2 bonds. At the same time, there are many polymerization reactions in thermal decomposition process, which may greatly affect the reaction rate and path. The higher the degree of polymerization, the larger equilibrium value of potential energy, the less energy release of thermal decomposition. Compared with the activation energy of other explosives, the activation energy of PTX is higher than that of β-HMX and lower than that of TNT.
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Affiliation(s)
- Yaojiang Li
- State Key Laboratory of Explosion Science and TechnologyBeijing Institute of TechnologyNo.5 Yard, Zhong Guan Cun South Street, Haidian DistrictBeijingChina
| | - Junying Wu
- State Key Laboratory of Explosion Science and TechnologyBeijing Institute of TechnologyNo.5 Yard, Zhong Guan Cun South Street, Haidian DistrictBeijingChina
| | - Lijun Yang
- State Key Laboratory of Explosion Science and TechnologyBeijing Institute of TechnologyNo.5 Yard, Zhong Guan Cun South Street, Haidian DistrictBeijingChina
| | - Deshen Geng
- State Key Laboratory of Explosion Science and TechnologyBeijing Institute of TechnologyNo.5 Yard, Zhong Guan Cun South Street, Haidian DistrictBeijingChina
| | - Manzoor Sultan
- State Key Laboratory of Explosion Science and TechnologyBeijing Institute of TechnologyNo.5 Yard, Zhong Guan Cun South Street, Haidian DistrictBeijingChina
| | - Lang Chen
- State Key Laboratory of Explosion Science and TechnologyBeijing Institute of TechnologyNo.5 Yard, Zhong Guan Cun South Street, Haidian DistrictBeijingChina
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17
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Ren C, Liu H, Li X, Guo L. Decomposition mechanism scenarios of CL-20 co-crystals revealed by ReaxFF molecular dynamics: similarities and differences. Phys Chem Chem Phys 2020; 22:2827-2840. [PMID: 31965130 DOI: 10.1039/c9cp06102a] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Understanding the similarities and differences of decomposition mechanisms of CL-20 and its cocrystals is of great interest for practical applications of CL-20 cocrystals. The responses of CL-20 cocrystals to thermal stimulus were investigated using ReaxFF molecular dynamics simulations of two representative cocrystals, CL-20/HMX and CL-20/TNT, under adiabatic conditions and comparing to the baseline system of pure CL-20. The comprehensive chemical details were revealed with the aid of the unique code of VARxMD. The three CL-20-involved reactive systems all exhibit a distinct three-stage character during adiabatic decomposition when using the double peaks of the major intermediate NO2 amount as the boundary. By taking advantage of the three-stage classification, a clear scenario for the similar stimulus-response of the CL-20 cocrystals can be elucidated for the dominant primary decomposition of CL-20 in stage I and the transition of favored chemical mechanisms from the generation of intermediates/radicals in stage II into their consumption to form stable products in stage III. The similar chemical behaviors are rooted in the dominance of CL-20 chemistry in the initial response of its cocrystals to thermal stimulus. The prolonged reaction zone uncovers the slowed decomposition kinetics of CL-20/HMX and CL-20/TNT, which is associated with the altered kinetics of CL-20 decomposition specifically by N-NO2 bond scission and CL-20 skeleton decay. The retarded CL-20 decomposition in its cocrystals consequently results in more moderate self-heating and less violent exothermic reactions that agrees with the experimental observations of improved stability and damaged detonation performance of CL-20 cocrystals, particularly for CL-20/TNT. The results obtained in this work suggest that ReaxFF MD simulations can provide useful insight for the modulated chemical properties of varied CL-20 cocrystals.
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Affiliation(s)
- Chunxing Ren
- State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, P. R. China. and University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Han Liu
- State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, P. R. China. and University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Xiaoxia Li
- State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, P. R. China. and University of Chinese Academy of Sciences, Beijing 100049, P. R. China and Innovation Academy for Green Manufacture, Chinese Academy of Sciences, P. R. China
| | - Li Guo
- State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, P. R. China. and University of Chinese Academy of Sciences, Beijing 100049, P. R. China and Innovation Academy for Green Manufacture, Chinese Academy of Sciences, P. R. China
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18
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Computational Studies of CL‐20‐based Materials. ChemistrySelect 2020. [DOI: 10.1002/slct.201904085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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19
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Zhang K, Chen L, Geng D, Lu J, Wu J. Thermal stability mechanism via energy absorption by chemical bonds bending and stretching in free space and the interlayer reaction of layered molecular structure explosives. Phys Chem Chem Phys 2020; 22:13248-13260. [DOI: 10.1039/d0cp01470b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Layered molecular structure explosives have the characteristic of great thermal stability.
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Affiliation(s)
- Kaining Zhang
- State Key Laboratory of Explosion Science and Technology
- Beijing Institute of Technology
- Beijing 100081
- China
| | - Lang Chen
- State Key Laboratory of Explosion Science and Technology
- Beijing Institute of Technology
- Beijing 100081
- China
| | - Deshen Geng
- State Key Laboratory of Explosion Science and Technology
- Beijing Institute of Technology
- Beijing 100081
- China
| | - Jianying Lu
- State Key Laboratory of Explosion Science and Technology
- Beijing Institute of Technology
- Beijing 100081
- China
| | - Junying Wu
- State Key Laboratory of Explosion Science and Technology
- Beijing Institute of Technology
- Beijing 100081
- China
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20
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Kiselev VG, Goldsmith CF. Accurate Prediction of Bond Dissociation Energies and Barrier Heights for High-Energy Caged Nitro and Nitroamino Compounds Using a Coupled Cluster Theory. J Phys Chem A 2019; 123:4883-4890. [DOI: 10.1021/acs.jpca.9b01506] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Vitaly G. Kiselev
- School of Engineering, Brown University, 184 Hope Str., Providence, Rhode Island 02912, United States
- Novosibirsk State University, 2 Pirogova Str., 630090 Novosibirsk, Russia
- Institute of Chemical Kinetics and Combustion SB RAS, 3 Institutskaya Str., 630090 Novosibirsk, Russia
| | - C. Franklin Goldsmith
- School of Engineering, Brown University, 184 Hope Str., Providence, Rhode Island 02912, United States
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21
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Bidault X, Chaudhuri S. A flexible-molecule force field to model and study hexanitrohexaazaisowurtzitane (CL-20) – polymorphism under extreme conditions. RSC Adv 2019; 9:39649-39661. [PMID: 36105179 PMCID: PMC9429022 DOI: 10.1039/c9ra07645j] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 11/13/2019] [Indexed: 12/28/2022] Open
Abstract
The quantum-chemistry based force field (FF) developed for HMX by Smith and Bharadwaj (SB) [G. D. Smith and R. K. Bharadwaj, J. Phys. Chem. B, 1999, 103(18), 3570–3575] is transferred to another nitramine of different stoichiometry: hexanitrohexaazaisowurtzitane (CL-20 or HNIW). The modification of a single parameter alongside a very small number of add-ons related to carbon–carbon bonds, angles and dihedrals lead to two SB FF variants denoted SB-CL20 and SB-CL20 + CCNN. These flexible-molecule FFs should inherit the predictive capabilities of SB FF. For this purpose, we perform Molecular Dynamics simulations at ambient temperature and selected pressures. The modeled structures of the various CL-20 polymorphs are consistent with experimental data. Focusing on the ε-polymorph, we determine an equation of state which consolidates the general trend underpinned by most published results, and we confirm the increasing stiffness of the crystal under pressures up to 90 GPa. Moreover, we link some subtle pressure-induced changes of the elastic and structural properties to the flexibility and mobility of well-identified nitro groups. Finally, the simulations of the γ ↔ ζ phase transition suggest different multiple-step direct and reverse thermodynamic paths. The quantum-chemistry based force field developed by Smith and Bharadwaj is transferred to hexanitrohexaazaisowurtzitane (CL20), revealing pressure-induced alterations of ε-CL20.![]()
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Affiliation(s)
- X. Bidault
- Department of Civil and Materials Engineering
- University of Illinois at Chicago
- Chicago
- USA
| | - S. Chaudhuri
- Department of Civil and Materials Engineering
- University of Illinois at Chicago
- Chicago
- USA
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