超低温重结晶法制备纳米FOX-7及性能研究

为了制备出粒径均匀且分散性较好的纳米FOX-7,采用液氮超低温重结晶法在不同溶剂条件下制备了纳米FOX-7;采用场发射扫描电子显微镜(FE-SEM)、X射线衍射(XRD)、傅里叶变换红外光谱(FT-IR)、差示扫描量热法(DSC)、热重分析法(TG)对所制备的纳米FOX-7的性能进行了表征,并测试了其撞击感度和摩擦感度。结果表明,所制备的纳米FOX-7的平均晶粒度为30nm左右,颗粒平均粒径均在100~200nm之间;与原料FOX-7相比,其高低温分解放热峰之间的温度范围变窄,能量释放效率及分解放热焓有较大提高,撞击感度和摩擦感度明显降低。不同溶剂由于其溶解度和极性的不同,所制备样品的颗粒粒径有所不同,溶解度与极性越大,所制备的颗粒粒径越小、热性能越好、感度更低。当溶剂为N-甲基吡咯烷酮时,所制备的纳米FOX-7的颗粒粒径在100nm以下占比为18%,初始分解峰温提高了11.8℃,分解放热焓提高了19%,特性落高从87.2cm提高至138.2cm,摩擦感度从216N提高至360N。

Preparation of Nano-sized FOX-7 by Ultra-low-temperature Recrystallization and Its Properties

In order to obtain nano-sized and uniform 1,1-diamino-2,2-dinitroethylene(FOX-7)particle with good dispersion,nano-FOX-7 was prepared by liquid nitrogen ultra-low-temperature recrystallization method in different solvents.The properties of the prepared FOX-7 were characterized by field emission scanning electron microscopy(FE-SEM),X-ray diffraction(XRD),fourier transform infrared spectroscopy(FT-IR),differential scanning calorimetry(DSC)and thermogravimetric analysis(TG),and the impact and friction sensitivity of FOX-7 were tested.The results show that the average grain size of the prepared nano-FOX-7 is about 30 nm,and the average particle size is in the range of 100-200nm;Compared to the raw FOX-7,the temperature difference between the low and high temperature on the decomposition exothermic peaks of the prepared nano FOX-7 becomes small,and its energy release efficiency and decomposition enthalpy greatly increase,the impact and friction sensitivities significantly reduced.Due to the difference in solubility and polarity of solvents,the particle size of the prepared samples is distinct.The larger the solubility and polarity,the smaller the particle size.It resulted into better thermal performance and lower sensitivity.When the solvent is N-methylpyrrolidone,the prepared nano FOX-7 with the particle sizes of below 100nm accounts for 18%,its initial decomposition peak temperature increases by 11.8℃,and the decomposition enthalpy increases by 19%.The characteristic drop height increases from 87.2cm to 138.2cm,and the friction sensitivity increases from 216N to 360N.