Nozzle‐Assisted Simultaneous Precipitation Method for Energetic FOX‐7/RDX Composite Microspheres with Improved Thermal Stability and Sensitivity

• Published in: Crystal research and technology (1979) 2020-07, Vol.55 (7), p.n/a
• Main Authors: Xu, Ruixuan, An, Chongwei, Ye, Baoyun, Liu, Qian, Wang, Jiechao, Wang, Jingyu
• Format: Article
• Language: English
• Subjects: energetic composite; FOX‐7/RDX; impact sensitivity; NASP method; thermal stability
• ISSN: 0232-1300; 1521-4079
• DOI: 10.1002/crat.202000015

Energetic 1,1‐diamino‐2,2‐dinitroethylene/hexahydro‐1,3,5‐trinitro‐1,3,5‐triazine (FOX‐7/RDX) composite crystals are fabricated via a newly introduced method named nozzle‐assisted simultaneous precipitation. Dimethyl sulfoxide is used as the solvent and FOX‐7/RDX composite crystals are prepared at different molar ratios of FOX‐7 and RDX. Regularly spherical FOX‐7/RDX particles are obtained under the 1:1 molar ratio of FOX‐7 and RDX and confirmed by field emission scanning electron microscopy. The result characterized by a laser particle size analyzer shows that the FOX‐7/RDX composite particles have a narrow particle size distribution with a median diameter of ≈1.57 µm. The structure of FOX‐7/RDX particles is confirmed using powder X‐ray diffraction and Fourier transform infrared spectroscopy, and the patterns suggest differences compared with FOX‐7/RDX mixture by mechanical mixing. Differential scanning calorimetry and thermal gravimetric test show an advanced decomposition peak temperature compared with raw FOX‐7 and RDX, and the apparent activation energy (Ea) of FOX‐7/RDX composite particles increases by 72.44 kJ mol−1 than that of raw RDX. Furthermore, the characteristic drop height of FOX‐7/RDX composite particles increases to 61.9 cm, which is a 111.3% increasement compared to raw RDX, indicating an obviously significant improvement concerning mechanical safety. A rapid preparation process named nozzle‐assisted simultaneous precipitation method is introduced to fabricate sub‐micrometer/micrometer spherical 1,1‐diamino‐2,2‐dinitroethylene/hexahydro‐1,3,5‐trinitro‐1,3,5‐triazine (FOX‐7/RDX) composite under the 1:1 molar ratio of FOX‐7 and RDX, which shows an enhanced thermal stability and significant improvement in impact safety performance.