Molecular Dynamics Simulations Guide Solvent Etching for the Preparation of High-Performance Spherical DAP-4.

As the first metal-free molecular perovskite energetic material, (H2dabco)[NH4(ClO4)3]DAP-4 has attracted significant research interest globally for its excellent thermal stability, superior detonation performance, and good moisture resistance. The crystal form of energetic materials plays a crucial role in determining the energy output and safety performance. To obtain spherical DAP-4 crystal particles, the effect of different solvents on the growth morphology of DAP-4 was studied. Based on the simulation and experimental results, a suitable mixed solvent system was selected, and spherical DAP-4 was successfully prepared by the solvent-etching method. The influence of process parameters on the morphology and particle size of DAP-4 crystals was studied. The morphology and particle size distribution of DAP-4 crystals were characterized, and the thermal decomposition behavior, combustion properties, and mechanical sensitivity of spherical DAP-4 were examined and discussed. The results show that spherical DAP-4 can be obtained under conditions of a solvent/nonsolvent volume ratio of 1:2, a temperature of 40 °C, and an experimental duration of 3 h. Compared to raw DAP-4, the bulk density and tapped density of spherical DAP-4 increased by 35.1% and 11.0%, respectively. The thermal decomposition peak temperature of spherical DAP-4 is close to that of raw DAP-4, indicating that spheroidization did not reduce the thermal stability of DAP-4. The combustion performance of spherical DAP-4 was significantly improved. In addition, the impact sensitivity of spherical DAP-4 increased by 23.17%, and the probability of explosion decreased by 12% compared to raw DAP-4. Based on these findings, a sensitivity-reducing mechanism for spherical DAP-4 was proposed.