The Formation Mechanism Of Impurity And Preparation Of High Purity Nano-TATB

Nano explosives have faster energy release speed, better selectivity of sensitivity and detonation performance, which are widely used in many applications like high burning rate propellant、high damage munitions and micro-energetic devices. 1,3,5-triamino-2,4,6-trinitrobenzene(TATB) is the only single-compound explosive which meets the standards of insensitive high explosives(IHE), but excessive desensitization limits the wide application of TATB in energetic devices. The nanocrystallization of TATB could regulate its energy release speed and response sensitivity to specific stimulus, which enables TATB to meet special using requirements. At present, the sulfuric acid is mainly used as solvent in the nanocrystalliztion of TATB, however, the strong acidity and oxidizability of concentrated sulfuric acid make the purity of nano-TATB very low. Therefore, this dissertation studied the structures and the formation mechanism of impurities by theoretical and experimental methods. On that basis, the preparation method of high-purity nano-TATB was explored. The main contents are as follows:(1) Experimental characterization and B3 LYP theoretical simulation method were used to study the structure and formation mechanism of sulphur-containing impurity in the nanocrystallization of TATB with concentrated sulfuric acid as solvent. Results show that the impurity was 1,3,5-triamino-2,4,6-trinitro-2,5-cyclohexadiene bisulfate, it was produced from the protonation of TATB molecule.(2) In order to study the carbon impurity of nano-TATB, which was prepared by concentrated sulfuric acid, a series of experiments was designed to promote the carbonization process. In addition, the formation mechanism of carbon impurity was investigated by quantum chemistry method. Results show that, due to the strong dehydration property of concentrated sulfuric acid, the amino and nitro groups in TATB molecule were dehydrated to form monomer、dimer、tetramer.(3) The high-purity nano-TATB(1,3,5-triamino-2,4,6-trinitrobenzene) was prepared by spraying recrystallization with trifluoromethanesulfonic acid as solvent and water as non-solvent. The influence of technological conditions on the particle size of nano-TATB was studied. By controlling the process conditions, the nano-TATB with purity of 98.1% and particle size of 60 nm was obtained.