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

18th APS-SCCM; 24th AIRAPT

Bishop, M.M.^1,2 ; Chellappa, R.S.^3 ; Liu, Z.^4 ; Preston, D.N.^5 ; Sandstrom, M.M.^5 ; Dattelbaum, D.M.^1 ; Vohra, Y.K.^6 ; Velisavljevic, N.^1

Shock and Detonation Physics Group, Los Alamos National Laboratory, Los Alamos

NM

87545, United States^1

Department of Chemistry, University of Alabama at Birmingham, Birmingham

AL

35294, United States^2

Los Alamos Neutron Science Center, Los Alamos National Laboratory, Los Alamos

NM

87545, United States^3

Geophysical Laboratory, Carnegie Instiution of Washington, 5251 Broad Branch Road NW, Washington

DC

20015-1305, United States^4

High Explosives Science and Technology Group, Los Alamos National Laboratory, Los Alamos

NM

87545, United States^5

Department of Physics, University of Alabama at Birmingham, Birmingham

AL

35294, United States^6

关键词: Ambient pressures;    Gamma phase;    High pressure;    Isobaric heating;    Low sensitivity;    Mid-infrared spectroscopy;    Secondary explosive;    Structural phase transition;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/500/5/052005/pdf
DOI  :  10.1088/1742-6596/500/5/052005

来源: IOP

【 摘 要 】

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 α → β (∼160 °C) structural phase transitions; as well as, indicated an additional transition γ → (∼210 °C), with the δ phase being stable up to ∼251 °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 °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.