Production of desensitized, ultrafine PETN powder

Preparation and Characterization of Ultrafine Nitroguanidine with Different Aspect Ratios

In order to improve the mechanical properties and thermodynamic stability of the long needle-like raw material Nitroguanidine (NQ), it was pulverized by a mechanical pulverization method and dried by a spray drying method, and three ultrafine NQ samples with different aspect ratios (2.26, 1.87, and 1.25) were prepared. The samples were tested and characterized by scanning electron microscopy, digital imaging particle size analysis, X-ray diffraction, and differential scanning calorimetry (DSC), and the impact sensitivity and bulk density of the raw NQ and ultrafine NQ samples were also tested. The results show that ultrafine NQ has the smallest particle size D50 of 9.18 μm, with uniform particle size distribution, unchanged crystal structure, and no introduction of impurities, and the impact sensitivity was the same as that of the feedstock NQ, which was 0. In addition, with the decreasing aspect ratio of the NQ particles, their apparent activation energy increased, and the energy required to be absorbed in the thermal decomposition increased; their thermal stability was also better.

Microstructural and Sensitivity Changes of Neat, Spray-Dried RDX

Spray drying has recently gained interest in the high explosives (HE) community for the production of novel nanocomposites and well-controlled particle size distributions. However, there is a dearth of information on spray-dried, neat energetic materials. In this work, we correlate the spray drying production parameters to the resulting microstructure and handling sensitivity properties of neat RDX. We demonstrate the capability to fine-tune the particle size distributions for "nanopowder" spray-dried RDX, as well as larger particle size distributions by simply changing the spray dryer setup. We also investigate other physical and chemical changes that RDX undergoes after being processed with spray drying. We characterize these changes with scanning electron microscopy, X-ray diffraction, ultrahigh-performance liquid chromatography, and small-scale sensitivity tests. Interestingly, although the phase and chemical properties are similar before and after spray drying, small-scale sensitivity testing reveals that size reduction of RDX does not follow the typical HE desensitization trends, generally observed for other energetic materials.