Application of microfluidic technology on preparation of nano LLM-105

Current methods, including ball milling and spray drying, are subject to some restrictions in application for preparing nano 2,6-diamino-3,5-dinitropyrazine-1-oxide (LLM-105), such as too large volume of dangerous goods, unstable temperature as well as discontinuous industrial production. In this study, continuous and safe preparation of nano-LLM-105 was achieved using microfluidic technology. Several influence factors had been studied on the particle size of LLM-105 including supersaturation, microreactor structure, solvent/non-solvent ratio, the total flow rate, reactor temperature, as well as the number of plates. Results showed that supersaturation of solution and structure of the microreactor played a critical role in the formation of nano-scale LLM-105. Further analysis on these nano-particles revealed its D50 was 124.95 nm with a spherical-like narrow shape through scanning electron microscopy and particle size distribution curve. X-ray diffraction results show that the crystal structure of nano-LLM-105 has not changed, and the differential scanning calorimeter test results show that nano-LLM-105 still maintains good thermal stability compared to raw-LLM-105. In short, this protocol provides a new route for continuous and safe preparation of nano-level LLM-105, which could be potentially applied to other nano-energetic materials, such as HMX and CL-20.