纳米结构高氯酸铵的制备及其性能和防吸湿性研究

Preparation,sensitivity and anti-hygroscopicity of nano-AP

为了减小高氯酸铵(AP)的粒径,进一步提高AP性能,采用液氮辅助和真空冷冻干燥法制备出n-AP,并通过扫描电镜(SEM)、X射线衍射(XRD)、X光电子能谱(XPS)和红外光谱(IR)对其进行表征,使用差示扫描量热法(DSC)和热重-质谱(TG-MS)分析其热分解性能,同时测试其机械感度;并分别用1%油酸和1%KH-550对n-AP进行表面包覆改性,测试包覆前后n-AP的吸湿性,并与AP进行对比。结果表明,所制备的n-AP微观形貌呈长条形,一维尺寸小于100 nm,其分子结构、表面元素和晶相与AP一致;n-AP的热分解活化能为128.14 kJ/mol,较AP降低18.68 kJ/mol,说明纳米化后热稳定性下降;n-AP的热分解产物为NH_(3)、H_(2)O和NO,另有少量HCl、NO_(2)和Cl_(2)生成;n-AP的机械感度有一定恶化,5 kg落球下特性落高(H_(50))为71 cm,摩擦感度爆炸百分比(P)为96%,与AP相比分别提高了14.5%和56%;经包覆改性后,n-AP的吸湿性大幅度降低。其中,1%KH-550包覆的n-AP的吸湿性最低,为1.38%。

In order to reduce the particle size of AP and improve its performance,nanoscale ammonium perchlorate(nano-AP)was prepared by means of the liquid nitrogen assisted and vacuum freeze-drying method,which were characterized by scanning electron microscopy(SEM),X-ray diffractometry(XRD),infrared spectroscopy(IR),and X-ray photoelectron spectroscope(XPS).The thermal decomposition of nano-AP was investigated by Differential scanning calorimetry(DSC)and thermal-mass spectrometry online(TG-MS).The impact sensitivity and friction sensitivity of raw materials and nano-AP were also tested.The surface coating of nano-AP was modified with 1%oleic acid and 1%KH-550,respectively.The hygroscopicity of nano-AP before and after coating was tested and compared with raw AP.The results show that nano-AP exhibits an enlongated micro morphology,which is less than 100 nm in one-dimension.The molecular structure,surface elements,and crystal phase of nano-AP are consistent with those of raw AP.The activation energy of thermal decomposition of nano-AP is 128.14 kJ/mol,which is 18.68 kJ/mol lower than that of raw materials,indicating that the thermal stability of nano-AP is decreased.The thermal decomposition products of nano-AP are NH_(3),H_(2)O,NO and a small amount of HCl,NO_(2)and Cl_(2).The characteristic drop height(H_(50))of 5 kg drop ball is 71 cm,and the explosion percentage(P)of friction sensitivity is 96%,which increases by 14.5%and 56%in comparison with raw AP,respectively.After coating modification,the hygroscopicity of nano-AP is greatly reduced,and 1%KH-550 coated nano-AP shows the lowest hygroscopicity,which is 1.38%.