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 D 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.