Structure Design And Performance Study Of CL-20 Based Host-guest Complexes

The design and preparation of high energy density materials(HEDMs)with desired properties is one of the hotspots in the research of energetic materials.As a practical non-nuclear elemental explosive,CL-20 brings new opportunities for the development of explosives due to its high energy and excellent explosive properties.Nevertheless,the high mechanical sensitivity and easily exhibit phase transition has hindered its practical applications.Many experimental and theoretical studies have been devoted to improving the performance of energetic materials by exploring a variety of new strategie.However,it remains challenging to design and construct energetic crystals with the highest possible energy density and the maximum possible chemical stability owing to the contradictory relationship between power and safety.Tuning its structure by embedding oxidizing molecules between the molecules of HEDMs to construct host-guest complexes is a feasible strategy to improve the explosive energy.However,Under the same conditions(temperature,pressure,etc.),the comparison of the stability,detonation performance and other parameters between the host-guest energetic complexes which were constructed by embedding different small molecules into the crystal lattice cavity of α-CL-20 have not yet been realized.Meanwhile,due to the limitations of existing conditions,there are still relatively few studies devoted to exploring more host-guest energetic complexes by introducing novel small molecules.Therefore,a series of new α-CL-20-based host-guest complexes were obtained by embedding different small molecules into the crystal cavity of anhydrous α-CL-20.Using a combination of density functional theory and experiment,the structure,interaction,stability and detonation performance of a series of host-guest complexes were studied.The crystal structure of α-CL-20/H2O and α-CL-20/N2O revealed by power X-ray diffraction(PXRD)are less than 10%of the calculated results,and the thermal stability order of α-CL-20/N2O,α-CL-20/CO2,α-CL-20/H2O andα-CL-20/H2O2 measured by differential scanning calorimeter(DSC)are also consistent with the order predicted by simulation.Therefore,the combination of simulation and experiment proves the reliability of the calculation method.The stability of different host-guest structures was compared in vacuum,and the influence of intermolecular interactions,oxygen balance and guest small molecular weight on the stability of host-guest complexes were discussed.In view of the various factors affecting performance of the high-energy explosives,such as the detonation performance,thermal stability,and density,we conclude thatα-CL-20/O3 could be regarded as the potential target high-energetic compounds.Based on the above results,this calculation method can provide a theoretical basis for the preparation of CL-20 based host-guest energetic compounds.