微流控法制备纳米硼复合微球及其燃烧性能研究OA北大核心CSTPCD

To solve the problems of easy to be agglomerate,difficult to be ignited,with slow burning rate,and incomplete energy release of nano-sized boron powder(nB),droplet microfluidic technology was used to prepare the nB/NC composite microspheres through fluid focused microchannels by using an aqueous solution with a surfactant mass fraction of 2％as the con-tinuous phase,a ethyl acetate solution of nB as the dispersed phase,and nitrocellulose(NC)as the binder.The effect of two-phase flow velocity ratio and dispersed phase mass fraction on the particle morphology,particle size,and sphericity of nB/NC composite microspheres were carried out,and the optimal process conditions were obtained.The combustion performance of nB composite microspheres was tested by using boron/potassium nitrate ignition powder formula.The thermal decomposition performances of raw nB and composite microspheres in the atmosphere were tested by TG-DSC method.The results indicate that the optimal process for preparing nB composite microspheres by microfluidic method is suspension mass fraction of 5％,binder of NC,dispersed phase flow rate of 0.075 mL/min,and continuous dispersed phase flow rate of 1 mL/min.The particle size of nB composite microspheres is between 50-70 μm.The particle size distribution is uniform and the flowability is good.The thermal decomposition peak temperature is advanced by 41.6 ℃,and the activation energy increases by 0.95 kJ/mol.The maximum combustion pressure reaches 1.78MPa,and the maximum combustion temperature reaches 1 601 ℃.Compared with the raw nB,the prepared composite microspheres have better thermal reactivity and combustion performance.