The Morphology Prediction Of CL-20 Crystal And Investigation On Energetic Cocrystals Characteristics

CL-20(also known as hexanitrohexaazaisowurtzitane)is a kind of explosive with the highest energy density synthesized in recent years,which has been widely used in military and civil fields.However,the CL-20 particles obtained through the initial crystallization operation have irregular morphology,high sensitivity and low safety coefficient,which have some limitations in the practical application.Studies have shown that improving the morphology of CL-20,such as making it have a near-spherification morphology,can effectively reduce its sensitivity.Therefore,the study on the spherification technology of CL-20 has become one of the research hotspots in the field of energy-containing materials.The research methods mainly include experimental methods and theoretical prediction.Cocrystal is the union of two or more substances by non-covalent forces,such as intermolecular hydrogen bonding,?-?stacking,and electrostatic interaction so on.At present,the research on energetic cocrystal is still in the exploratory stage,and most of it relies on the experiment experience of the synthesizer,lacking certain theoretical basis and guidance.In this paper,CL-20 and its cocrystals were studied from the aspects of morphology improvement and cocrystals.In this paper,the molecular dynamics method and modified attachment energy model were first used to predict the crystal morphology of CL-20 under different crystallization conditions.The effects of the types of good and bad solvents and the proportion of good and bad solvents on the crystal morphology were systematically investigated.On this basis,the suitable crystallization conditions were selected and the theoretical prediction results were verified by anti-solvent crystallization experiments.Theory and practice verify each other.On the one hand,a theoretical method is established to predict the crystal morphology by using the modified attachment energy model;on the other hand,the crystallization conditions for the preparation of spherical CL-20 are obtained to promote its application in the field of energy-containing materials.For the study of cocrystal,two models for predicting the cocrystal density of 60 kinds of energetic cocrystals with the ratio of molecular number to 1:1 synthesized in the current Cambridge crystal library are established.The first model is the prediction model of energetic cocrystal density based on the artificial neural network model.The model used six parameters as factors affecting cocrystal density,which are the two substances that make up the cocrystals,?₁ and?₂,the three descriptors(Ms,E1u,RTm)in E-dragon software which are correlate with the density of the crystal,the strongest hydrogen bond interaction(E_hb),and then an artificial neural network approach was used to predict the cocrystal density.The second kind of prediction model of energetic cocrystal is based on the prediction of the density of single crystal.In this paper,the least square method is used to calculate the density of eutectic energy.The method of theoretical calculation is used to predict the density of energetic cocrystal,which provides a powerful theoretical guidance for the experimental synthesis of energetic cocrystal and the regulation of cocrystal density.In order to find a method to screen CL-20 formers molecules,the structure and interaction between CL-20molecules and CL-20 formers molecules were calculated and analyzed in this paper with the currently reported synthesized CL-20 cocrystal as the research object.