Evidence for a High‐Pressure Phase Transition of ε‐2,4,6,8,10,12‐Hexanitrohexaazaisowurtzitane (CL‐20) Using Vibrational Spectroscopy

Ciezak, Jennifer A.; Jenkins, Timothy A.; Liu, Zhenxian

doi:10.1002/prep.200700209

Cited by 38 publications

(39 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The objective of the present study was to examine the room temperature isothermal structural stability and vibrational behavior of 1MNT when subjected to static highpressure using X-ray diffraction and vibrational spectroscopy. This work continues the series of investigations into the pressure-driven structural transformations of energetic materials through employment of a multi-technique approach [10,11]. The results from this study provide strong evidence that the ambient pressure phase remains the dominant phase to near 40 GPa, although slight decomposition of the material is observed starting near 16 GPa.…”

Section: Introductionmentioning

confidence: 55%

The High‐Pressure Characterization of Energetic Materials: 1‐Methyl‐5‐Nitramino‐1H‐Tetrazole

Ciezak

2010

Propellants Explo Pyrotec

Self Cite

View full text Add to dashboard Cite

Pressure -volume relations and optical Raman and Infrared spectra of polycrystalline 1MNT have been obtained under quasihydrostatic conditions up to 16 and 40 GPa, respectively, by using diamond anvil cell, synchrotron-based angle-resolved X-ray diffraction, and microspectroscopy. The X-ray measurements show that the pressure -volume relations remain smooth up to 16 GPa at room temperature, while vibrational measurements show no evidence of a phase transition to near 40 GPa. Anomalous increases of several vibrational intensities and bandwidths suggest that subtle molecular distortions and structural modifications occur in the crystal as pressure increases. Decompression experiments indicate the structural modifications are reversible.

show abstract

Section: Introductionmentioning

confidence: 55%

The High‐Pressure Characterization of Energetic Materials: 1‐Methyl‐5‐Nitramino‐1H‐Tetrazole

Ciezak

2010

Propellants Explo Pyrotec

Self Cite

View full text Add to dashboard Cite

show abstract

“…Therefore, it is necessary and meaningful to explore the pressure behaviors for energetic materials. Except for studying the phase transitions and decomposition mechanism of CL‐20 under pressure, early study has made a clear knowledge about the structural characterization of a high‐pressure phase of CL‐20 through experiments . Gump et al investigated the structural changes of ϵ‐CL‐20 under high pressure, showing that the unit cell volume decreased under compression and no phase was observed up to 6.3 GPa .…”

Section: Introductionmentioning

confidence: 99%

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)

View full text Add to dashboard Cite

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.

show abstract

“…The different extended orientations of the nitro groups relative to the five-or six-membered rings of HNIW leads to different molecular packing models and different numbers of molecules in a cell, which defines several probable polymorphs of HNIW. So far, five different polymorphs (α, β, γ, ε, and ζ) have been reported and identified [10][11][12][13][14]. Four of the polymorphs (α, β, γ, and ε) exist at ambient pressure and temperature.…”

Section: Introductionmentioning

confidence: 99%

Thermally Induced Polymorphic Transformation of Hexanitrohexaazaisowurtzitane (HNIW) Investigated by in-situ X-ray Powder Diffraction

Liu¹,

Li²,

Ze-shan³

et al. 2016

Cent. Eur. J. Energ. Mater.

View full text Add to dashboard Cite

Abstract:The ε→γ phase transition of HNIW induced by heat was investigated with in situ X-ray powder diffraction (PXRD). The effects of purity, particle size, insensitive additives and the time of isothermal heat treatment on the phase transition were evaluated. It was found that the phase transition is irreversible with changes in temperature, and the two phases can coexist in a certain temperature range. Moreover, the initial phase transition temperature increases with increasing purity and decreasing particle size of HNIW, and thus with the approximate crystal density. The addition of graphite and paraffin wax to HNIW as insensitive additives leads to a decrease in the initial phase transition temperature, but the addition of TATB does not affect the initial phase transition temperature. Thus, TATB is a suitable insensitive additive. Moreover, at the critical temperature, the isothermal time determined the efficiency of the ε-to γ-phase transition. This work lays the foundations for the choice of molding technologies, performance test methods, ammunition storage options, as well as the manufacture of HNIWbased explosive formulations.

show abstract

Evidence for a High‐Pressure Phase Transition of ε‐2,4,6,8,10,12‐Hexanitrohexaazaisowurtzitane (CL‐20) Using Vibrational Spectroscopy

Cited by 38 publications

References 20 publications

The High‐Pressure Characterization of Energetic Materials: 1‐Methyl‐5‐Nitramino‐1H‐Tetrazole

The High‐Pressure Characterization of Energetic Materials: 1‐Methyl‐5‐Nitramino‐1H‐Tetrazole

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

Thermally Induced Polymorphic Transformation of Hexanitrohexaazaisowurtzitane (HNIW) Investigated by in-situ X-ray Powder Diffraction

Contact Info

Product

Resources

About