Continuous pipe-stream self-assembly technology for preparation of high sphericity FOX-7/HMX energetic composite microspheres

The emphasis on producing high-energy and insensitive composite microspheres has increased in energetic materials. However, few methods are available for preparing good spherical and morphological composite microspheres. To produce composite microspheres that are both high-energy and safe, in this article, a continuous pipe-stream self-assembly device was constructed to produce FOX-7/HMX composite microspheres continuously and taking advantage of the principle that PVA and Tween-80 can reduce the surface tension of the microspheres in water. In comparison with the molding powders produced by the kneading way, the FOX-7/HMX composite microspheres prepared by this device had fewer surface defects, a denser structure, a more spherical shape, and a smaller range of particle sizes. The mechanical properties of the pressed columns were better, with maximum compressive strength and strain increased by 44.2% and 21.4%, respectively; and the flowability and bulk density were also improved to some extent (angle of repose: energetic microspheres vs kneading method molding powder, 26.6° vs 51.1°; bulk density: energetic microspheres vs kneading method molding powder, 0.522 vs 0.426 g/cm3). Mechanical sensitivity has also been significantly reduced. This article provides innovative ideas for preparing high-energy and insensitive composite microspheres using a continuous pipe-stream self-assembly device.