Microstructural and Sensitivity Changes of Neat, Spray-Dried RDX

Abstract

Spray drying has recently gained interest in the high explosives (HE) community for the production of novel nanocomposites and wellcontrolled 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.

Investigation of Physical and Chemical Properties of TNT after Spray Drying

“…This shows that the change in starting material between the as-received or recrystallized does not drastically change the end product morphology after spray drying. The spray drying of TNT forms much smaller-sized particleson the order of one to a few micronswith smooth particle faces and rounded edges, which is typically the case for other spray-dried HE particles. ,,,, The final particle size of the spray-dried TNT is the nozzle size used in the process. We used the smallest nozzle size available for our spray drying unit (0.7 mm) to achieve the very fine particle size, as shown in Figure .…”