Preparation, characterization of spherical 1,1-diamino-2,2-dinitroethene (FOX-7), and study of its thermal decomposition characteristics

The sensitivity and properties of energetic materials strongly depend on their crystal morphology. In this article, spherical 1,1-diamino-2,2-dinitroethylene (FOX-7) was produced via a combination of the cooling crystallization method and repeated grinding technique. X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), optical microscopy, scanning electron microscopy (SEM) and laser particle size analysis were used to characterize the structure, infrared characteristics, morphology, and particle size of the product. The results show that the obtained product has a smoother spherical morphology with granularity gradation and shows similar diffraction peak positions to raw FOX-7. Differential scanning calorimetry (DSC), thermal gravimetry (TG), and accelerating rate calorimetry (ARC) were used to analyse the thermal behavior of spherical FOX-7 under nonisothermal and adiabatic conditions. The thermal performance test results show that spherical FOX-7 releases energy faster and releases more energy as compared to raw FOX-7. These findings showed that the cooling crystallization method combined with the repeated grinding technique is suitable for efficient preparation of spherical FOX-7, which could greatly improve the thermal stability of FOX-7.