Facile, continuous and large-scale production of core-shell HMX@TATB composites with superior mechanical properties by a spray-drying process

The increasing high-energy-density requirements of energetic materials as well as the concerns over safety problems have accelerated the development of insensitive high explosives (IHEs). Recently, studies focused on the fabrication of advanced combinations of materials such as coating a moderately powerful and extremely insensitive explosive 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) onto the surface of a high-energy but sensitive explosive 1,3,5,7-tetranitro-1,3,5,7-tetrazocane (HMX) have attracted a large amount of attention. However, the reported results on the construction of this core-shell structure show a low utilization of shell material due to the unconfined synthesis environment. In this report, a facile and effective spray-drying route was employed to achieve a coating of TATB nanoparticles onto pre-modified HMX crystals. The utilization of TATB shell was significantly improved due to the self-assembly in confined droplets during spray-drying process, thus leading to the decrease of shell content and further enhancement of explosive performance. Both field-emission scanning electron microscopy (FE-SEM) and X-ray photoelectron spectroscopy (XPS) results confirmed the formation of the core-shell HMX@TATB composites with a uniform and compact shell layer. The influence of various experimental parameters on the core-shell structure of final products was also examined. The impact and friction sensitivity results showed that superior mechanical properties of these core-shell microparticles can be maintained. Furthermore, such a facile, continuous, and one-step synthesis strategy opens up new perspectives on the large-scale production of core-shell energetic-energetic composites.