High pressure-temperature polymorphism of 1,1-diamino-2,2-dinitroethylene
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Univ. of Alabama at Birmingham, Birmingham, AL (United States)
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- Carnegie Institution of Washington, Washington, D.C. (United States)
- Univ. of Alabama at Birmingham, Birmingham, AL (United States)
Here, 1,1-diamino-2,2-dinitroethylene (FOX-7) is a low sensitivity energetic material with performance comparable to commonly used secondary explosives such as RDX and HMX. At ambient pressure, FOX-7 exhibits complex polymorphism with at least three structurally distinct phases (α, β, and γ). In this study, we have investigated the high pressure-temperature stability of FOX-7 polymorphs using synchrotron mid-infrared (MIR) spectroscopy. At ambient pressure, our MIR spectra and corresponding differential scanning calorimetry (DSC) measurements confirmed the known α → β (~110 °C) and β → γ (~160 °C) structural phase transitions; as well as, indicated an additional transition γ → δ (~210 °C), with the δ phase being stable up to ~251 degree C prior to decomposition. In situ MIR spectra obtained during isobaric heating at 0.9 GPa, revealed a potential α → β transition that could occur as early as 180 degree C, while β → β+δ phase transition shifted to ~300 °C with suppression of γ phase. Decomposition was observed slightly above 325 °C at 0.9 GPa..
- Research Organization:
- Univ. of Alabama, Birmingham, AL (United States)
- Sponsoring Organization:
- USDOE National Nuclear Security Administration (NNSA)
- Grant/Contract Number:
- NA0002014
- OSTI ID:
- 1251169
- Journal Information:
- Journal of Physics. Conference Series (Online), Vol. 500, Issue 5; ISSN 1742-6596
- Publisher:
- Institute of Physics (IOP)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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