Studyon Recrystallization Process For Spheroidization Of PETN

In this paper , the morphology control technology of explosives at present is comprehensively analyzed. The influence of different solvents and additives on the PETN crystalline morphology is discussed by molecular dynamics simulation. Predicted morphology has been compared with the experimentally found morphology of PETN crystallized from several solvent by evaporation crystallization. Effects of solvent,temperature,dilution rate and additive on the crystal morphology and impact sensitivity is studied according to the crystal growth theory. The influence of recrystallization process and particle size on the impact sensitivity is analyzed according to the Hotspot theory. A set of spheroidization technique of PETN is found on the basis of previous studies. The main contents of the study are as follows:The influence of solvents such as acetone,ethyl acetate,dimethylformamide and several additives on the PETN crystal morphology is studied by molecular dynamic simulation. Morphological changes of PETN crystallized from different solvent with additives and no additives is theoretically predicted. The mechanism of crystal morphology change deeply discussed through theoretical calculations. Predicted results are right verified by solvent evaporation crystallization experiments.The effect of different factors including solvent-non-solvent system temperature dilution rate of non-solvent and stirring speed on morphology of PETN is investigated by single-factor experiment . Crystal shape,size and surface defects is observed with optical microscope and Metallographic microscope. The influence mechanism of various factors on shape of particles is discussed according to crystal growth theory.Impact sensitivity of PETN gotten from single-factor experiment and particle size gradation is tested by impact sensitivity machine. The influence of recrystallization technique and particle size on PETN impact sensitivity is studied .The test of single-factor experiment showed that special height is 14.6cm when ethyl acetate as solvent,temperature 50℃, dilution rate 0.10mL/min,stirring speed 100r/min. Test of impact sensitivity after size Gradation showed influence of particle size on impact sensitivity of PETN recrystallized from ethyl acetate and acetone respectly is different. The bigger PETN particle gotten from ethyl acetate is low-sensitive.The solvent-non-solvent recrystallization technology of preparing spherical PETN particle with regular shape even distribution and low sensitivity is worked out by orthogonal experiment. Experimental results showed that spherical PETN particle is low sensitive with special height 15.5cm and can be got when ethyl acetate as solvent,temperature 50℃,dilution rate 0.10ml/min ,stirring speed 120r/min ,adding span20 of 0.5%.In this paper, most of experiment is a kind of exploratory study,the results showed the spherical particles of PETN with low sensitivity can be prepared by changing the recrystallization process.Some research results in this paper has a certain guidance value to the study of spheroidization of simple substance explosive.