Insensitive Technical Research Of Coated HMX By NTO Recrystallization

A charge of another kind of explosive by solution recrystallization method was still relatively rare in the domestic so far and the research of the method is more in-depth in foreign country.To reduce the mechanical sensitivity of HMX and maintain its detonation performance,HMX was coated with relatively insensitive explosive by solution crystallization method. So recrystallization coated process of the explosive had vital significance.The different crystal morphology of coated HMX was respectively obtained by NTO recrystallization in different solvents such as ethanol,N-N-dimethyl formamide-water, N-methyl pyrrolidone-water.The results showed different solvents had a great influence on the morphology of coated HMX.When ethanol was regarded as solvent,particles of coated HMX on the surface was lesser,surface coating was uniform,but in ethanol solvent coated amount was small,coated adhesion force was small,and not all HMX particles could be evenly coated.When we regarded N-N-dimethyl formamide-water,N-methyl pyrrolidone-water as the solvents,surface morphology of coated HMX particles was mainly influenced by the NTO concentration,cooling rate,stirring speed,solvent-the solvent ratio etc factors.The conclusion could be drawed when N-N-dimethyl formamide-water,N-methyl pyrrolidone-water regared as the solvents,the shape of coated HMX was similar to the spherical,the surface was evenly and had good viscosity.and it was found that the cooling rate was the main factors.Finally by means of scanning electron microscope(SEM),the impact sensitivity inst-rument of WL-type IIA,the friction sensitivity instrument of MGY-type I,the ZBS-10A100MHz ten video intelligent detonation velocity measuring instrument,morphology,the impact sensitivity,friction sensitivity,detonation velocity of coated HMX were analyzed. Coated HMX of the better morphology tested its impact sensitivity,friction sensitivity,d-etonation velocity and other performance parameters.The experiment showed that when the concentration of HMX was0.0277g/g,NTO concentration was0.0829g/g,the cooling rate was6k/min,mixing speed was300rpm,temperature range was80-5℃and the ratio of water and NMP was5,the performance of coated HMX was the best.Under the condition of mixed NMP-water solvents, H50of coated HMX increased14.8cm,the impact sensitivity was reduced by66%,the friction sensitivity from100%to50%.And detonation velocity of coated HMX was reduced by2.8%.Under the condition of mixed DMF-water solvents,H50of coated HMX increased17.6cm,the impact sensitivity was reduced by79%,the friction sensitivity from100%to40%.And after coated HMX detonation velocity decreased about1.8%. So explosive performance of HMX could basically remain the same by solution crystallization method.