水性聚氨酯乳液包覆硝酸肼镍及其性能研究

摘要

The waterborne polyurethane emulsion was prepared through self-emulsification method.The nickel hydrazine nitrate was coated by a demulsification method.The process parameters affecting the coating efficiency and mechanical sensitivities of coated sample were analyzed.The crystal type,surface morphology,decomposition temperature of nickel hydrazine nitrate before and after being coated were characterized by infrared spectroscopy, X-ray diffraction (XRD),scanning electron microscope (SEM)and differential thermal analysis.The fraction sensitivity and flame sensitivity were tested.The results show that the crystal structure of coated nickel hydrazine nitrate is unchanged.It belongs to the physical absorption coating.With the increase of dosage of waterborne polyurethane emulsion,consists of the surface functional groups of nickel hydrazine nitrate do not change,while the intensity of characteristic vibration peaks of polyurethane is accordingly enhanced.The decomposition temperature of coated sample is risen from 232℃ to 259℃.The detonation pressure value of friction sensitivity is risen from 35MPa to 318 MPa,showing good insensitive coating effects.The optimum conditions of coating process are:demulsifica-tion temperature,40℃;demulsification time,15 min;dropping rate of demulsifier,1 drop per second and the mass ratio of demulsifier to polyurethane,15∶1.%通过自乳化法制备了水性聚氨酯乳液，采用破乳法对硝酸肼镍进行钝感包覆，分析了影响包覆效果及样品机械感度的工艺参数。用红外光谱、X 射线衍射、SEM、差热分析对包覆前后硝酸肼镍的晶型、表面形貌、分解温度进行了表征，测试了其摩擦感度和火焰感度。结果表明，破乳包覆后硝酸肼镍的晶体结构不变，属于物理吸附包覆，且随着水性聚氨酯乳液用量的增加，表面官能团组成并无改变，聚氨酯特征振动峰的强度相应增强；包覆后硝酸肼镍的分解温度从232℃升至259℃；摩擦感度起爆压力值由35 MPa 升至318 MPa，钝感包覆效果良好。最佳的包覆工艺条件为：破乳温度40℃，破乳时间15 min，破乳剂滴加速率1滴／s，破乳剂与聚氨酯质量比15∶1。