Accurate and efficient droplet microfluidic strategy for controlling the morphology of energetic microspheres

An effective method is proposed for preparing energetic microspheres by fluid-focusing microchannels. This method combines the advantages of low reagent consumption, instrument miniaturization, accurate control, and efficient heat mass transfer. The effects of the two-phase liquid flow rate ratio of water to oil on droplet formation was fully studied. To verify the applicability of the method, the nitroamine explosives HMX (cyclotetramethylene tetranitramine) was employed with the fluorine rubber (F2602) as binder to prepare HMX/F2602 microsphere, which were compared with the samples prepared by traditional water-suspension method. SEM data showed that the morphology, particle size uniformity, and monodispersity of microspheres prepared by the droplet microfluidic method are better than those prepared by traditional water-suspension method. DSC data showed that the suspension method. DSC data showed that the apparent activation energy (Ea) values of HMX/F2602 increased by 25.47 kJ/mol compared with the water-suspension coated sample. Meanwhile, compared with the raw material HMX, the H50, the fluidity and bulk density of HMX/F2602 microspheres were significantly improved (HMX/F2602 microsphere and raw HMX: H50 = 86.9 and 25.2 cm, repose angle = 33.1 and 51.3°, bulk density = 0.714 and 0.604 g cm−3). This study demonstrates the feasibility of an efficient, accurate strategy to prepare the explosive microspheres.