| The microstructure control of hexanitroguanidine(2,2’,4,4’,6,6’-Hexanitrostilbene,HNS),the first choice for slapper detonator charge,has received extensive attention.In addition to refinement,porosity is also an important method for the regulation of HNS microstructure.Porous HNS has the small size effect of micro-nano building unit,and there are synergistic effects and coupling effects between building units.It is expected to improve the combustion and detonation performance of existing HNS,reduce its impact initiation threshold,and improve the safety and stability of its energy output.In this thesis,porous HNS was constructed based on supramolecular assembly-disassembly method,and the porous structure of HNS was regulated by various solvation and desolvation methods.Not only porous HNS with different pore size and morphology was obtained,but also the mechanism of the influence of HNS porous structure on its mechanical sensitivity and impact initiation performance was discussed,which can provide a new idea for the microstructure control and performance improvement of explosives.The main research contents include:(1)Preparation and performance of porous HNSThe HNS/dioxane prepared by the cooling crystallization method was used as a template,and the anti-solvent extraction method was developed for the supramolecular disassembly of HNS/dioxane.By comparing with the existing vacuum drying disassembly method,it is found that both the thermal action and the solvent action can obtain porous HNS with similar morphology and structure,and the structure of the porous HNS mainly depends on the molar ratio of acetone to water in the extraction solvent.The safety and detonation performance test results show that the introduction of porous structure had little effect on the thermal properties of HNS(decomposition temperature was 353.3°C),but the impact sensitivity and friction sensitivity were significantly reduced by 14.7% and 18.7%,respectively,while the shock wave sensitivity was significantly improved,and the calculated detonation current was 1640 A.(2)Pore structure adjustment and performance study of porous HNSThe pore structure of the porous HNS was adjusted by supramolecular assembly-disassembly.A supramolecular assembly method,vacuum vapor infiltration method,was developed for the assembly of porous HNS.Compared with the existing hot vapor infiltration method,the vacuum vapor infiltration method can better maintain the particle shape integrity.The porous HNS/dioxane was disassembled by vacuum drying method and anti-solvent extraction method,respectively.The results show that the disassembly process can not only produce new pores but also connect the original pores to produce larger pores,thus forming HNS with multi-scale pore structure.The experimental results show that the thermal properties of the porous HNS are basically unchanged after the supramolecular assembly-disassembly(the decomposition temperature is 353.9°C),but the impact sensitivity and friction sensitivity are further reduced,which are 9.7% and 5.3%,respectively.The shock wave detonation threshold is further reduced,and the calculated detonation current is 1536 A.(3)Exploratory research on TNBFI supramolecular assemblyThe supramolecular assembly method was applied to the exploratory research on TNBFI supramolecular assembly,and it is expected to provide a template for constructing a special structure of TNBFI.The solvate of the HNS energetic derivative TNBFI,TNBFI-DMF,was obtained by adding the tertiary amine additive PMP to the DMF solution of HNS,and studied its structural and thermal properties after solvent removal.In addition,four new TNBFI solvates were prepared by different crystallization methods using TNBFI obtained from solvent removal,the crystal structure of four TNBFI solvates was analyzed by single crystal X-ray diffraction analyzer,and its morphology and thermal properties were characterized.These four TNBFI solvates provide templates for the construction of special structural TNBFI. |
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