Molecular dynamics simulation on thermal decomposition mechanism of CL-20with different polymorphs
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摘要: 基于反应力场，采用NPT、NVT系综和Berendsen方法，对ε-、β-和γ-CL-20超晶胞在不同温度下的热分解反应过程进行分子动力学计算。结果表明：3种晶型CL-20的初始分解路径均是五元环和六元环中的N-NO2键断裂生成·NO2自由基，生成的主产物包括N2、H2O、CO、CO2、NO2、NO3、HNO2、HNO3、N2O5、N2O2和NO等。相同晶型的CL-20发生热分解生成的主产物的反应速率常数随温度的升高而增大。Abstract: The initial thermal decomposition pathways of the supercell structures of ε, β and γ modifications at different temperatures were studied by molecular dynamics simulations, using the ReaxFF force field, the NPT and NVT ensembles and the Berendsen methods.The results show that the initial pathway of different CL-20polymorphs is only the N-NO2dissociation to forming·NO2radical fragments, and the main thermal decomposition products are N2, H2O, CO, CO2, NO2, NO3, HNO2, HNO3, N2O5, N2O2and NO.The reaction rate constants of main products with the same modification increase with the increasing of temperature.
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Key words:
- mechanics of explosion /
- reaction pathway /
- thermal decomposition /
- CL-20 /
- polymorphs /
- reaction rate constants
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图 3 γ-CL-20中目标温度和平均势能随时间的变化
Figure 3. Time evolution of temperature and potential energy in the thermal decomposition of γ-CL-20
图 4 γ-CL-20超晶胞生成的平均碎片数量随时间的变化
Figure 4. Number of fragments per molecular in the thermal decomposition of γ-CL-20
图 5 不同温度下γ-、β-和ε-CL-20热分解碎片数量
Figure 5. Fragment number per molecular in the different polymorphys of CL-20
图 6 不同温度时γ-CL-20发生分解反应生成的主产物和中间体数量随时间的变化
Figure 6. Time evolution of fragment number in the thermal decomposition of γ-CL-20supercell at different temperatures
图 7 2 000K时β-和ε-CL-20发生热解反应生成的主产物和中间体数量随时间的变化
Figure 7. Time evolution of fragment number in the thermal decomposition of β-andε-CL-20supercells at 2 000K
图 8 不同温度时γ-CL-20发生热解反应生成的主产物和中间体数量随时间的变化
Figure 8. Time evolution of fragment number in the thermal decomposition of γ-CL-20supercell at different temperatures
图 9 2 500K时β-和ε-CL-20发生热解反应生成的主产物和中间体数量随时间的变化
Figure 9. Time evolution of fragment number in the thermal decomposition of β-andε-CL-20supercells at 2 500K
图 10 单分子和超晶胞ε相CL-20生成的产物
Figure 10. The final products in the thermal decomposition of ε-CL-20molecule and supercell
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[1] Simpson R L, Urtiev P A, Ornellas D L, et al. CL-20performance exceeds that of HMX and its sensitivity is moderate[J]. Propellant, Explosives, Pyrotechnics, 1997, 22(5): 249-255. doi: 10.1002/prep.19970220502 [2] Patil D G, Brill T B. Thermal decomposition of energetic materials 59: Characterization of residue of hexanitrohexaazaisowurtzitane[J]. Combustion and Flame, 1993, 92(4): 456-458. doi: 10.1016/0010-2180(93)90155-V [3] Okovytyy S, Kholod Y, Qasim M, et al. The mechanism of unimolecular decomposition of 2, 4, 6, 8, 10, 12-hexanitro-2, 4, 6, 8, 10, 12-hexaazaisowurtzitane: A computational DFT study[J]. The Journal of Physical Chemistry A, 2005, 109(12): 2964-2970. doi: 10.1021/jp045292v [4] Isayev O, Gorb L, Qasim M, et al. Ab initio molecular dynamics study on the initial chemical events in nitramines: Thermal decomposition of CL-20[J]. The Journal of Physical Chemistry B, 2008, 112(35): 11005-11013. doi: 10.1021/jp804765m [5] 张力, 陈朗, 王晨, 等. CL-20初始热解反应机理的分子动力学计算研究[J].火炸药学报, 2012, 35(4): 5-9. doi: 10.3969/j.issn.1007-7812.2012.04.002Zhang Li, Chen Lang, Wang Chen, et al. The mechanism of the initial thermal decomposition of CL-20via molecular dynamics simulation[J]. Chinese Journal of Explosives & Propellants, 2012, 35(4): 5-9. doi: 10.3969/j.issn.1007-7812.2012.04.002 [6] Van Duin A C T, Dasgupta S, Lorant F, et al. ReaxFF: A reactive force field for hydrocarbons[J]. The Journal of Physical Chemistry A, 2001, 105(41): 9396-9409. doi: 10.1021/jp004368u [7] Bolotina N B, Hardie M J, Speer R L, et al. Energetic materials: Variable-temperature crystal structures of γ- and ε- HNIW polymorphs[J]. Journal of Applied Crystallography, 2004, 37(5): 808-814. doi: 10.1107/S0021889804017832 [8] Foltz M F, Coon C L, Garcia F, et al. The thermal stability of the polymorphs of hexanitrohexaazaisowurtzitane[J]. Propellants, Explosive, Pyrotechnics, 1994, 19(1): 19-25. doi: 10.1002/prep.19940190105 [9] 傅献彩, 沈文霞, 姚天扬, 等.物理化学[M]. 5版.北京: 高等教育出版社, 2006: 163-165. -
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