Study On Preparation Of Nano/micron HMX And Control Technique Of Crystallization Quality

Nano/micron explosive compound and nano/micron Composite Energetic Materials havewidely applied to military for their superior physical and chemical properties. In order tomake the composition of Energetic Materials nano/micron-sized, the sol-gel method and sprayrefining method were used to prepare the nano/micron-sized nergetic materials in this paper,and then the nano/micron-sized nergetic materials using the two methods of preparation werecharacterized.But, the refined HMX are liable to grow up together, so that the refined effectloses its significance. This paper is aimed at this practical problem, in order to study thetechnological approaches to control the quality of refining crystallization of HMX.The experiments were carried out using sol-gel method, with Cr （NO₃）₃·9H₂O as Gelprecursor body, with 1, 2-propylene oxide （C₃H₆O） as gelling agent, to prepare HMX/Cr₂O₃wet gel by dissolving HMX into N,N-Dimethyl Formamide solution, and finally through thesupercritical drying method to get the aerogel of HMX/Cr₂O₃, whose structures werecharacterized and sensitivity was tested then. Furthermore, HMX was refined to sub-micronlevel by method of Spray refinement of crystallization in the process, and then changingsolvents and drying methods could control the crystal forms and crystal growth, and finallythe mechanical sensitivity tests were carried out for the refined elemental crystals.With the analysis of its shapes and structures by scanning electron microscope （SEM）,the results show that orderly gel holes in Cr₂O₃Gel grid could effectively control the growthof crystals of HMX, in addition that the composite particles of HMX/Cr₂O₃have a moreintegrated structure. Especially in the process of Spray refinement of crystallization, adding alittle PVP can effectively control crystal growth, and the thinning particles ranges from 1 to 2 μm and uniform size. What’s more, the mechanical sensitivities of the prepared nano-sizedHMX/Cr₂O₃composite and HMX raw materials and refined HMX are all tested. The testresults show that the hit sensitivity of the nano-sized HMX/Cr₂O₃composite is 74.15cm,whose value is much lower than the HMX raw materials 22.39cm, and its friction sensitivityis no significant changes in comparison with HMX raw materials. The hit sensitivity of therefined HMX by ventilation drying with DMF as solvent is 49.66cm, the hit sensitivity of therefined HMX by freezing drying with DMSO as solvent is 61.18cm and the hit sensitivity ofthe refined HMX by ventilation drying with 0.4% of the PVP as additive is 77.98cm, whosevalues are much lower than the HMX raw materials 22.39cm, and its friction sensitivity is nosignificant changes in comparison with HMX raw materials as well.