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Title: High pressure-temperature polymorphism of 1,1-diamino-2,2-dinitroethylene

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..
Authors:
 [1] ;  [2] ;  [3] ;  [2] ;  [2] ;  [2] ;  [4] ;  [2]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Univ. of Alabama at Birmingham, Birmingham, AL (United States)
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  3. Carnegie Institution of Washington, Washington, D.C. (United States)
  4. Univ. of Alabama at Birmingham, Birmingham, AL (United States)
Publication Date:
OSTI Identifier:
1251169
Grant/Contract Number:
NA0002014
Type:
Accepted Manuscript
Journal Name:
Journal of Physics. Conference Series (Online)
Additional Journal Information:
Journal Name: Journal of Physics. Conference Series (Online); Journal Volume: 500; Journal Issue: 5; Journal ID: ISSN 1742-6596
Publisher:
Institute of Physics (IOP)
Research Org:
Univ. of Alabama at Birmingham, Birmingham, AL (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE energetic materials; phase diagrams; high pressure