| TATB is a kind of high-energy and insensitive explosive with excellent thermal stability,and has broad application prospects.At present,the main production method of TATB is the trichlorobenzene method.Studies have found that chlorine-containing impurities can affect the thermal stability and detonation performance of TATB and cause metal corrosion during long-term storage and aging of materials.In order to solve the above problems,researchers have conducted alternative studies on the synthetic route of chlorine-free TATB.In this dissertation,chlorine-free TATB was prepared from phloroglucinol.The properties of chlorine-free TATB and the effects of impurities and crystal morphology on properties were studied.Chlorin-free TATB was synthesized from phloroglucinol through three steps of nitration,alkylation and amination.The thermal stability,sensitivity and detonation performance of chlorine-free TATB were studied and compared with traditional chlorine-containing TATB.The results show that the peak temperature of exothermic decomposition of chlorine-free TATB is 377.2?.Under the national military standard test conditions,its friction sensitivity and impact sensitivity are zero.When the pressure density is 1.847 g·cm-3,the explosion velocity reaches 7660 m·s-1,the explosion pressure is 25.9 GPa,and the explosion heat reaches 5.02 MJ·kg-1,comprehensive performance is superior to traditional chlorine-containing TATB.The thesis separated and identified impurities in chlorine-free TATB as1-amino-3,5-diethoxy-2,4,6-trinitrobenzene(AETB)and 1,3-diamino-5-ethoxy-2,4,6-trinitro(EDATB).For chlorine-free TATB and impurities,a new TATB purity analysis method was established by HPLC,which has higher accuracy.The linear correlation index of the method reached 0.9999,the relative standard deviation(RSD)was 1.01%,and the standard recovery rate was 99%?101%.The thermal stability of the impurities was studied by thermal analysis.The results show that the exothermic decomposition peak temperatures of EDATB and AETB are 121.4?and 109.2?lower than TATB,respectively,and obvious endothermic melting phenomena exist at 190.5?and 122.6?,respectively.According to the density function theory,the density,detonation speed and detonation pressure of EDATB are calculated to be5.6%,6.0%,and 14.8%lower than TATB,and the density,detonation speed and detonation pressure of AETB are 11.8%,12.5%,and 29.1%lower than TATB,respectively.Calculations show that as the impurity content in TATB increases,the detonation speed gradually decreases.Several different morphologies of chlorine-free TATB crystals were obtained by changing the recrystallization conditions.By studying the crystal structure,thermal stability,and decomposition kinetics of TATB crystals with different morphologies found thatdue to the regular morphology,reduced defects,and enhanced crystallinity of the sawtooth,spherical,and hexagonal sheet TATBs obtained by recrystallization,The apparent activation energy of jagged TATB crystals increased by 0.73 k J·mol-1,and the exothermic decomposition peak temperature increased by 6.2?.The activation energies of spherical and hexagonal flaky TATB crystals with more regular morphologies were increased by 10.94 k J·mol-1 and 10.62k J·mol-1,respectively,and their exothermic decomposition peak temperatures were increased by 14.3?and 14.7?,respectively. |
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