Defence Technology (Sep 2023)
One-step rapid preparation of CL-20/TNT co-crystal assembly and spheroidized coating based on droplet microfluidic technology
Abstract
Energetic materials pose challenges in preparation and handling due to their contradictory properties of high-energy and low-sensitivity. The emergence of co-crystal explosives is a new opportunity to change this situation. If the co-crystal explosive is coated into spherical particles with uniform particle size distribution, this contradiction can be further reduced. Therefore, binder-coated hexanitrohexaazaisowurtzitane/2,4,6-trinitrotoluene (CL-20/TNT) co-crystal microspheres were prepared by droplet microfluidic technology in this work. The coating effects of different binder formulations of nitrocellulose (NC) and NC/fluorine rubber (F2604) on the co-crystal spheres were studied. The scanning electron microscopy (SEM) results showed that the use of droplet microfluidic technology with the above binders can provide co-crystal microspheres with regular spherical morphology, uniform particle size distribution and good dispersion. X-ray diffraction (XRD), fourier-transform infrared (FT-IR), differential scanning calorimetry (DSC) and thermo-gravimetric (TG) methods were employed to compare the properties of the co-crystal microspheres, raw material and pure co-crystal. The formation of CL-20/TNT co-crystal in the microspheres was confirmed, and the co-crystal microspheres exhibited better thermal stability than the raw material and pure co-crystal. In addition, the mechanical sensitivity and combustion performance of the co-crystal microspheres were further studied. The results showed that the co-crystal microspheres were more insensitive than CL-20 and pure co-crystal, and displayed excellent self-sustained combustion performance and theoretical detonation performance. This study provides a new method for the fast, simple and one-step preparation of CL-20/TNT co-crystal microspheres, with binder coating, uniform particle size distribution, and excellent performance level.
