Preparation And Properties Research Of Spherical Composite Explosive Based On CL-20

Energetic materials and their application in weapon systems were the core of national defense science and technology and an important foundation for the high performance of weapons and ammunition.With the current changes in the war environment,weapons systems were increasingly demanding on the overall performance of energetic materials,such as more powerful performance and lower sensitivity.This required the modification of existing energetic materials to improve performance and meet the needs of the current national defense.There were many shortcomings in the traditional method of refining energetic materials.The newly developed recrystallization method shows excellent characteristics and broad prospects for development.In the field of energetic materials,composite technology as a novel modification technology could not only solve the contradiction between high energy and low sensitivity,but also improved other properties of explosives（such as density,oxygen balance,detonation velocity,etc.）,so that it had a better ability to adapt to the war.On the other hand,the shape,size and structure of the energetic material had a significant impact on the sensitivity and thermal decomposition and packing density.Hexanitrohexaazaisowurtzitane（HNIW,commonly known as CL-20）was currently one of the highest energy single explosives,however,because of its high sensitivity,its application had been limited.To improve the sensitivity of CL-20,using composite technology,the non-covalent bond of CL-20 and lower sensitivity nitro compounds at the molecular level to produce spherical with high energy,low sensitivity and excellent comprehensive performance composite explosives.In this dissertation,a series of spherical composite crystals of CL-20 explosive were explored by means of ultrasonic-assisted emulsion.The structure of CL-20explosive was investigated by SEM,PXRD,IR.Impact sensitivity tester and other testing methods to characterize and analyze the structure and performance of the composite crystal.The main work of the dissertation was as follows:（1）Ethyl acetate as solvent and water as non-solvent.The preparation of CL-20/DNBA（hexanitrohexaazaisowurtzitane/3,5-dinitrobenzoic acid）composite crystal was investigated.The morphology of the composite crystal was observed by scanning electron microscope,owning small crystal size.By analyzing the IR spectra and powder X-ray diffraction spectra of the composite crystal,we could preliminarily conclude that the hydrogen bond between DNBA and the nitroxide of CL-20 forms a hydrogen bond and the melting point of the crystal was higher than CL-20 about 20℃,the thermal decomposition of composite crystal was different from the individual components of the raw materials.Sensitivity test results showed that the impact sensitivity of CL-20/DNBA composite was 50.4 cm,which was significantly lower than that of CL-20(H₅₀=13 cm).（2）The CL-20/PNCB（hexanitrohexaazaisowurtzitazone/p-nitrochlorobenzene）composite crystal with a 1:1 molar ratio was prepared by ultrasonic-assisted emulsion method.The crystal was spherical with a smooth surface structure.The only thermal decomposition peak appeared at 242.52℃.Sensitivity test results show that the impact sensitivity of the CL-20/PNCB composite was H₅₀=63 cm,which was significantly lower than that of the raw material CL-20(H₅₀=13 cm).（3）The preparation of CL-20/PNA（hexanitrohexaazaisowurtzitane/p-nitroaniline）composite crystals with a molar ratio of 1:1 was investigated.The obtained crystals were spherical.DSC test results found that the crystal had a different thermal decomposition performance of each raw material components.The sensitivity test results showed that the impact sensitivity of CL-20/PNA composite was H₅₀=60.1 cm,which was significantly lower than that of the raw material CL-20(H₅₀=13 cm).（4）The preparation of CL-20/DNA（hexanitrohexaazaisowurtzitane/2,4-dinitroaniline）composite crystals with a molar ratio of 1:1 was investigated.The obtained crystals were spherical with a rough surface.The results of the DSC test showed that the thermal decomposition temperature of the crystal was close to that of the raw material CL-20.Sensitivity test results showed that the impact sensitivity of CL-20/DNA composite was57.8 cm,which was significantly lower than that of CL-20(H₅₀=13 cm).（5）Explore the CL-20/TNT（hexanitrohexaazaisowurtzitane/2,4,6-trinitrotoluene）,CL-20/DNB（hexanitrohexaazaisowurtzitane/1,3-dinitrobenzene）cocrystal was prepared with a molar ratio of 1:1,and the two crystals obtained were smooth spherical and uniform particle size distribution.The results of the DSC test showed that the thermal decomposition temperature of the CL-20/TNT eutectic was 254.8°C,and the thermal decomposition temperature of the CL-20/DNB eutectic was 249.8°C.Sensitivity test results showed that the impact sensitivity of CL-20/TNT cocrystal was H₅₀=57.8 cm,and the impact sensitivity of CL-20/DNB cocrystal was H₅₀=65.4 cm,it was significantly lower than that of CL-20(H₅₀=13 cm).