Study On Preparation, Characterization And Properties Of CL-20/DNP Cocrystal Explosive

Traditional single-compound explosives have been seriously restricted the application and development of modern military and high-efficient weapons. Eutectic explosive technology as a kind of novel modification technology, not only can solve the contradiction between high-energy and low-sensitivity, but also can improve the other properties of explosives(such as density, oxygen balance, detonation velocity and detonation pressure, etc.). The energetic cocrystallization can make the exoplosive better to adapt the battlefield. Hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane hexaazaisowurtzitane(HNIW, commonly known as CL-20) is one of the highest energy explosives, however the high sensitivity limits its application scope. In order to improve the safety of the CL-20 and make it to be a high-energy insensitive explosive, cocrystal technology in this paper is employed to combine the high-energy CL-20 and low sensitivity DNP by non-covalent bonds between the molecules, which is expected to prepare the new CL-20/DNP cocrystal explosive with high energy, low sensitivity, and excellent comprehensive performance.According to the analyes of the structures, groups and properties of CL-20, DNP were selected to be the conformer of CL-20. The cocrystal structure of CL-20/DNP was studied by the first principles calculation method. The results show that hydrogen bond is the main force for forming the cocrystal between CL-20 and DNP. CL-20/DNP cocrystal was prepared by solvent evaporation method with different solvents(solvent of ethyl acetate, acetone, ethanol), temperatures(25, 35 and 45°C) and molar ratios(CL-20:DNP = 3:2, 1:1, 2:3). The optimum scheme of solvent, temperature and molar ratio were confirmed in turn according to the XRD results. The solvent evaporation method is the optimum schemefor preparing the CL-20/DNP cocrystal when solvent, temperature and molar ratio are solvent of ethyl acetate, 35°C and in 3:2(CL-20:DNP) respectively.In addition, the electron microscope, XRD, IR, and DSC are used to analyze CL-20/DNP cocrystal explosive. Results suggest that the morphology of CL-20/DNP cocrystal explosive is white six prismatic. Compared with the XRD curve of CL-20 and DNP, part of the diffraction peak has been a marked increase or decrease. And there is a new diffraction peak at 42.35°. The analysis of DSC suggests that the decomposition properties of CL-20/DNP cocrystal explosive are different from CL-20 and DNP. The XRD curve was changed may mainly because of the reason that the decomposition temperature of CL-20/DNP cocrystal explosive is 215.47°C which is generated by the hydrogen bonding intermolecular interacions. The analysis of infrared spectrum shows that the part of the product functional groups changed obviously infrared absorption peak position deviation. Characterized by the result, CL-20/DNP eutectic product formation is mainly due to the weak interaction between CL-20 and DNP molecules(such as hydrogen bonds and van der Waals force). Meanwhile, the explosive impact sensitivity, vacuum stability, detonation velocity and detonation pressure of CL-20/DNP cocrystal explosive are tested and concluded. The results showed that the CL-20/DNP eutectic explosive impact sensitivity is lower than CL-20 of the impact sensitivity, the analysis of vacuum stability test suggests that CL-20/DNP cocrystal explosive has the good stability. Additionally, the detonation velocity and detonation pressure are larger than DNP with 9.8%, 16.7%, respectively. As a result, CL-20/DNP eutectic explosive meet the requirements of the development of explosive weapons today.