(449s) Effect of Supersaturation on Morphology in the Crystallization of an Energetic Material
The detonation characteristics of high energetic materials have been strongly affected by not only crystal shape, size distribution, and surface roughness, but also purity and internal structure. Especially, crystal shape and average diameter have determined the packing density and mechanical strengths of the energetic material when formulated with polymeric binder and other ingredients. Among most formulations, polyhedral or spherical particles are needed due to the spatial dissipation of mechanical stresses and increment of flowability exposed at blending, kneading and other processes. In the drowning-out crystallization of 4,10-dinitro-2,4,6,8,12tetraoxa-4,10-diazatetracyclo [5.5.0.05,9.03,11]-dodecane(TEX), size and shape of TEX crystal was controlled by initial supersaturation generated at the mixing of the anti-solvent with saturated TEX solution. Shapes of TEX particles were changed by the mixing pattern of the anti-solvent with solvent. Either rapid pulse or continuous injection of anti-solvent produced the irregular or needle-like particles with average diameters ranged 10 to 30 Î¼m. However, polyhedaral TEX particles with smooth surface were obtained at the slow feeding of anti-solvent into TEX solution. According to our experiments, higher supersaturation may not be preferable to obtain polyhedral particles. In the present work, initial supersaturations, saturation temperature and mixing rate were considered. Average diameter of TEX particles was 15 to 45 Î¼m with polyhedral, needle-like and plate depending on crystallization condition. Crystal structure was confirmed by the comparison of XRD patterns based on Karaghiosoffâ??s results.