Preparation of NQ/TATB composite microspheres based on oil-in-oil emulsion method: a novel strategy for enhancing process performance and thermal safety
摘要
Nitroguanidine (NQ) is an energetic material, which is widely used as a component of triple base propellants. As the third generation energetic material, NQ has the advantages of high detonation performance. However, the current industrial production of NQ has problems such as poor fluidity and low bulk density. In this study, NQ/TATB (1,3,5-triamino-2,4,6-trinitrobenzene) composite microspheres were prepared by oil-in-oil emulsification method. The effects of oil-in-oil volume ratio, surfactant type and concentration on the stability of emulsion were studied by optimizing the volume ratio of raw materials, so as to obtain the best preparation process parameters and improve the dispersion and bulk density of microspheres. The results showed that when the volume ratio of continuous phase/dispersed phase was 6/4, Tween-80 was used as surfactant, and its dosage was 0.8%, the emulsion stability was the best, and the NQ/TATB composite microspheres showed excellent spherical structure and clear particles under scanning electron microscope. It was found by XRD and FT-IR that the functional groups of NQ/TATB composite microspheres were basically the same as those of NQ and TATB raw materials, indicating that the two were well combined and no new groups were produced. At the same time, the specific surface area of the composite microspheres is larger than that of NQ, and the thermal stability is enhanced. Compared with the raw material NQ, the loose bulk density of the composite microspheres increased by 0.594 g cm−3, the tap bulk density increased by 0.688 g cm−3, the compression index decreased by 14.35, and the angle of repose decreased by 21°. The bulk density and fluidity of the composite microspheres were significantly enhanced.