The Investigation On The Process Of CL-20 Recrystallization

CL-20 is a high energy compound with good performance. As one of the high energy density materials, it is the most potential explosive for military as well as civil applications presently. However, it is sensitive and dangerous, which limits the fields to use. Thus, it is of importance and practical significance to reduce the sensitivity for CL-20.According to the investigation by Chen Huaxiong, the form of CL-20 crystal growth in vacuum has been simulated by Materials Studio (MS). Adsorption of acetone, ethyl acetate, water or Span surfactants on CL-20 crystal surface has been investigated with Molecular Dynamics Simulation. The scales of adsorption energies show that the system of acetone-water makes against the growth of CL-20 crystal, while in the ethyl acetate-chloroform system, the CL-20 crystal grows well. Moreover, the CL-20 crystal becomes an ordered crystal with the addition of Span surfactants because of their inhibition.The crystal growth of CL-20 in various solvents has been investigated using solvent-nonsolvent method with the help of previous theoretical analysis. The effect of crystallizing point, dripping speed of non-solvent, stirring rate or adding span surfactants on the crystal morphology of CL-20 has been presented. The result shows that the CL-20 can crystallize well in the ethyl acetate-chloroform system and the condition of the best crystallizing process of CL-20 is at 20℃, 0.15 mL/min of dripping speed, 100r/min of stirring rate as well as 0.04% mass of Span 60. The crystal morphology of CL-20 is nearly spherical and among the size of 120~135μm according to the best crystallizing process.The experiment shows that surfactant is the key factor for controlling crystal morphology and its mass concentration makes great effect on the crystal size. The impact sensitivity of CL-20 crystallized from systems mentioned in our investigation has been tested. The result shows that the h50 is improved from 19.00 to 45.31 cm with 2.5 kg drop hammer and the sensitivity of CL-20 is reduced greatly with the addition of surfactant.The investigation on morphology controlling technique of CL-20 is of great significance for monomer explosive.