Self-Assembly Method for Insensitive DAAF/FOX-7 Composite Crystals with Microspheres Structure

Highly efficient design for the formulation of explosives is desired for accelerating the development of energetic materials. These investigations are focused on the preparation of the compounds 3,3′-diamino-4,4′-azoxyfurazan (DAAF) and 1,1-diamino-2,2-dinitroethylene (FOX-7). DAAF/FOX-7 microspheres are prepared via the self-assembly method using different mass ratios of DAAF and FOX-7. Materials Studio is used to analyze the intermolecular binding energy (E_bind) of the composite system. DAAF/FOX-7 with a mass ratio of 90:10 shows a higher E_bind (183.24 kJ mol⁻¹) and peak temperature at the heating rate of 0 °C min⁻¹ (266.2 °C) than DAAF/FOX-7 with a mass ratio of 70:30 and DAAF/FOX-7 with a mass ratio of 80:20; this indicates that DAAF/FOX-7 (90:10) shows better thermal stability. EXPLO5 is used to analyze the detonation velocity of the composite system, and the detonation velocity of DAAF/FOX-7 microspheres increase by 0.5 km s⁻¹ compared to that of DAAF. The characteristic drop height of impact sensitivity is more than 100 cm, and this demonstrates that the microspheres exhibit good safety performance. The morphology, crystal structure, thermal decomposition property, and impact sensitivity of the microspheres are investigated and compared. X-ray diffraction and Fourier transform infrared spectroscopy results indicate that the structure of the DAAF/FOX-7 composite is not changed compared to that of the raw material.