Insights into the roles of two constituents CL-20 and HMX in the CL-20:HMX cocrystal at high pressure: a DFT-D study

Liu, Zhichao; Wu, Qiong; Zhu, Weihua; Xiao, Heming

doi:10.1039/c5ra01829c

Cited by 26 publications

(17 citation statements)

References 39 publications

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“…Most of the elastic constants show a remarkably increasing trend with the increasing pressure. C 15 and C 35 are found to be negative in a wide pressure region, which has been supported by Liu . In the pressure region of 0–15 GPa except for zero pressure, there exists a small difference among the elastic constants for C 11 , C 22 , and C 33 , satisfying the relationship of C 11 ≈ C 33 > C 22 .…”

Section: Resultssupporting

confidence: 57%

“…C 15 and C 35 are found to be negative in a wide pressure region, which has been supported by Liu. [24] In the pressure region of 0-15 GPa except for zero pressure, there exists a small difference among the elastic constants for C 11 , C 22 , and C 33 , satisfying the relationship of C 11 % C 33 > C 22 . It is suggested that the crystal shows much softness along a and c axes than b axis.…”

Section: Elastic Constants and The Related Propertiesmentioning

confidence: 84%

“…Using the density functional theory, previous studies have predicted the elastic constants of PETN‐I and β‐HMX . Recently, a DFT‐D study has been performed on CL‐20 and HMX to investigate the pressure effects in the cocrystal (CL‐20: HMX), and the mechanical properties of pure ϵ‐CL‐20 were involved . In addition, the electronic properties, especially band structures can provide significant information about the impact sensitivity for energetic materials.…”

Section: Introductionmentioning

confidence: 99%

“…[23] Recently, a DFT-D study has been performed on CL-20 and HMX to investigate the pressure effects in the cocrystal (CL-20: HMX), and the mechanical properties of pure e-CL-20 were involved. [24] In addition, the electronic properties, especially band structures can provide significant information about the impact sensitivity for energetic materials. Therefore, it is necessary to study the band structures of CL-20.…”

Section: Introductionmentioning

confidence: 99%

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Structures, Elasticity, and Sensitivity Characteristics of ɛ‐CL‐20 under High Pressure from First‐Principles Calculations

Zhong

Qin

Liu

et al. 2019

Physica Status Solidi (b)

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First‐principles calculations have been conducted for ɛ‐CL‐20 to study the pressure effects on the structures, elasticity, and sensitivity characteristics under 0–75 GPa. It is found that N–NO2 possesses smaller populations than other bonds and is verified as the trigger bond for ϵ‐CL‐20, and the nitrogen atoms on nitro groups (–NO2) are more sensitive to pressure than that on the rings. A detailed understanding of elasticity has been studied and discussed under pressure. In general, the mechanical properties of ɛ‐CL‐20 are distinctly enhanced under compression. The obtained elastic constants show better agreement with the experiment at zero pressure. As the pressure increases, the lattice interactions towards different directions present pronounced difference. A relationship of C11 ≈ C33 > C22 is obtained in the lower pressure region. However, a different relationship of C11 > C22 ≈ C33 is predicted under higher pressure. The crystal, ɛ‐CL‐20, changes from brittleness to plasticity according to the sharp increase of B/G and C12–C44 under compression. And the band gap of ɛ‐CL‐20 decreases with the increasing pressure, indicating the crystal becomes more sensitive under compression.

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Section: Resultssupporting

confidence: 57%

Section: Elastic Constants and The Related Propertiesmentioning

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Structures, Elasticity, and Sensitivity Characteristics of ɛ‐CL‐20 under High Pressure from First‐Principles Calculations

Zhong

Qin

Liu

et al. 2019

Physica Status Solidi (b)

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“…As early as in 1978, the 1,3,5,7-tetranitro-1,3,5,7-tetrazocane/ammonium perchlorate (HMX/AP) cocrystal was prepared by a decompression solvent evaporation method in which the hydrophobicity of AP was substantially improved. 10 Subsequently, researchers prepared 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane/2,4,6-trinitrotoluene (CL-20/ TNT), 11 CL-20/HMX, [12][13][14] 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12hexaazaisowurtzitane/dinitrobenzene (CL-20/DNB), 15 1,3,5triamino-2,4,6-trinitrobenzene/1,3,5,7-tetranitro-1,3,5,7-tetrazocane (TATB/HMX), 16 and other cocrystal explosives [17][18][19] and reduced the sensitivity of explosives to a certain extent. For example, the nano CL-20/HMX explosive was prepared with the spray drying method.…”

Section: Introductionmentioning

confidence: 99%

Mechanochemical fabrication and properties of CL-20/RDX nano co/mixed crystals

et al. 2018

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By milling 2,4,6,8,10,4,6,8,10, and hexahydro-1,3,5trinitro-1,3,5-triazine (RDX) together, a nano CL-20/RDX co/mixed crystal explosive with a mean particle size of 141.6 nm is prepared from the raw materials, and the co/mixed crystals are characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy, infrared (IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), differential scanning calorimetry (DSC) and thermal-infrared spectrometry online (DSC-IR) technology; furthermore, the impact, friction and thermal sensitivity of the samples are tested. The results show that after milling, the morphology of the co/mixed crystal explosive is near-spherical, and the particle size reveals a normal distribution. The milled sample showed the same molecular structure and surface elements as the raw materials, but the XRD test shows that CL-20/RDX has a new crystal phase and the Raman and IR spectra gave a supplementary confirmation for the existence of a cocrystal phase in the milled sample. The activation energy of the thermal decomposition of CL-20/RDX is 206.49 kJ mol À1 higher than that of raw RDX. DSC-IR analysis showed that the thermolysis of CL-20/RDX produces a large amount of CO 2 and N 2 O and a small amount of H 2 O, NO 2 and NO. The mechanical sensitivity of CL-20/ RDX is very low. In impact sensitivity tests with a 5 kg hammer, the special height (H 50 ) is 51.43 cm, which is higher than the values of 36.43 cm for raw CL-20 and 9.78 cm for raw RDX. In the friction sensitivity tests, the explosion probability (P) is 56%; however, the thermal sensitivity of CL-20/RDX is higher than that of the raw materials, with its 5 s burst point being only 243.51 C. rsc.li/rsc-advances 34126 | RSC Adv., 2018, 8, 34126-34135 This journal is

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Thermal decomposition mechanisms of the energetic benzotrifuroxan:1,3,3‐trinitroazetidine cocrystal using ab initio molecular dynamics simulations

Xie

Zhu

2019

J Chinese Chemical Soc

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Ab initio molecular dynamics simulations were performed to investigate the thermal decomposition mechanisms of the energetic benzotrifuroxan (BTF):1,3,3‐trinitroazetidine (TNAZ) cocrystal at high temperature. It is found that there are four initial reaction mechanisms involved in the decomposition of the cocrystal. Subsequent decomposition channels can be divided into three types: BTF‐chain isomerization, C─NO2 bond homolysis, and ring opening. After that, one main path is that long chains decomposed into small radicals gradually after the ring opening. The other is that a new ring was formed after the ring opening and then it will break by degrees. Releasing of the H radicals and oxygen‐containing groups plays an important role in the whole decomposition process. We also studied the release mechanisms of nitrogen gas and carbon dioxide in the later decomposition stage. Our study may provide new insights into the initiation mechanisms and subsequent decomposition of cocrystal explosives at high temperature.

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Insights into the roles of two constituents CL-20 and HMX in the CL-20:HMX cocrystal at high pressure: a DFT-D study

Abstract: The two constituents HMX and CL-20 produce different effects on the crystal structure of their cocrystal in different directions.

Cited by 26 publications

References 39 publications

Structures, Elasticity, and Sensitivity Characteristics of ɛ‐CL‐20 under High Pressure from First‐Principles Calculations

Structures, Elasticity, and Sensitivity Characteristics of ɛ‐CL‐20 under High Pressure from First‐Principles Calculations

Mechanochemical fabrication and properties of CL-20/RDX nano co/mixed crystals

Thermal decomposition mechanisms of the energetic benzotrifuroxan:1,3,3‐trinitroazetidine cocrystal using ab initio molecular dynamics simulations

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