1,1-Diamino-2,2-dintroethene (FOX-7) nanocrystals embedded in mesoporous carbon FDU-15

Insensitive energetic materials are considerably desirable for insensitive munitions or low vulnerability ammunition compositions because of the reduced risks involved with their use. The ability to control compositions and properties for such materials is also of interest since it can lead to optimal performance, controlled energy release, and low sensitivity. With these goals in mind, we focus our work on a high energy density material, 1,1-diamino-2,2-dinitroethylene (FOX-7). FOX-7 nanocrystals under confined conditions are synthesized in mesoporous carbon FDU-15 through self-assembly. Complete impregnation can be achieved in N-methyl-2-pyrrolidone at 100–110 °C, and the maximum amount of FOX-7 in the FOX-7/FDU-15 composites is around 43.8 wt.% (C-43.8). Host–guest interactions are investigated by wide-angle XRD, 13C solid-state NMR, and FT-IR. C-43.8 shows low phase transition temperature and fast thermal decomposition rate compared with bulk FOX-7 crystals and the physical mixture. The host–guest structure of the composites demonstrates a novel and efficient space-insensitivity concept. C-43.8 shows no sensitivity toward both friction and impact, and insensitive to electrostatic spark (V50 > 37 kV; E50 > 20 J). The extreme insensitivity is closely related to the high thermal and mechanical stability of FDU-15.

FOX-7 self-assembled to form nanocrystals in FDU-15.Figure optionsDownload as PowerPoint slideHighlights
► High explosive 1,1-diamino-2,2-dinitroethylene (FOX-7) self-assembled to form nanocrystals in mesoporous carbon FDU-15.
► Confinement effects of FDU-15 on 1,1-diamino-2,2-dinitroethylene nanocrystals were investigated.
► The FOX-7/FDU-15 composites showed low phase transition temperature and fast thermal decomposition rate.
► The FOX-7/FDU-15 composites showed extreme insensitivity to accidental stimuli.