| The Dihydroxylammonium 5,5'-Bistetrazole-1,1'-diolate(TKX-50)is a new elemental explosive with high energy level and low mechanical sensitivity.TKX-50 has better performance than HMX and is highly expected to be used as a HMX substitute.Explosive crystal form has a great impact on its process performance and safety performance.By controlling the crystal formation conditions,we can control the crystal morphology,improve the crystal quality and reduce the sensitivity.In this paper,after analyzing the properties of TKX-50,the effects of additive on the morphology of TKX-50 were studied by using several kinds of additives with organic small molecule and surfactant.And several groups of crystalline systems with good morphology were obtained.In the hundred grams of scale scale,the effect of crystallization process on the crystal morphology of TKX-50 was further studied.And the preferred spheroidal TKX-50 preparation process conditions were obtained.The effects of two kinds of additives,such as water as solvent,organic small molecule and surfactant,on the morphology of TKX-50 were studied on the scale of laboratory experiment,and the crystal morphology was observed under scanning electron microscopy.The results showed that the addition of organic small molecule ethylene glycol,ethanol,formic acid and acetic acid recrystallization after TKX-50 crystal morphology is good,the sample particle size distribution;the surface of the TKX-50 crystal was re-crystallized with sodium dodecyl sulfonate and cetyltrimethylammonium bromide,and the sample size distribution was uniform.On the laboratory small scale,the amount of additives was further studied and we found: adding 10% ethylene glycol,ethanol,formic acid,acetic acid;or 0.2% sodium dodecyl sulfonate,0.05% cetyltrimethylammonium bromide during recrystallization can obtain the crystal which the morphology was small,the crystal shape was regular and the distribution was uniform.The recrystallization process with sodium dodecyl sulfonate as an additive and water as the solvent was optimized by partial process to obtain the recrystallization process condition which could obtain better crystal morphology.Dissolved the TKX-50 completely at 90 ?.Then cool down to 70~75°C when a small amount of crystals were precipitated.Add 0.20% sodium dodecyl sulfonate,0.05% added TKX-50 inoculating seed.Control the stirring speed of 600 r / min and the cooling rate of 0.5 °C / min.Cool down to 10 ? when crystallization.The effects of water as solvent,ethylene glycol,ethanol,formic acid,acetic acid,CTAB and sodium dodecylsulfonate as additives on the morphology of TKX-50 were studied on the hundred grams of scale scale.It was concluded that TKX-50 with good crystalline morphology can be obtained by adding recrystallization system of sodium dodecylsulfonate after observing the crystal morphology.After further optimizing the process conditions,a recrystallization process which can obtain a spherical TKX-50 was obtained.Dissolved the TKX-50 completely at 90 ?.Then cool down to 70~75 ? when a small amount of crystals were precipitated.Add 0.22% sodium dodecylsulfonate,control the stirring speed of 600 r / min and the cooling rate of 0.5 ? / min.Cool down to 10 ? when crystallization.Compared with TKX-50 raw materials,the size of TKX-50 crystal which under suitable conditions was uniform,the aspect ratio was significantly decreased,and the crystal was spherical.The thermal decomposition of spherical TKX-50 samples was studied.The results showed that the thermal decomposition of TKX-50 was composed of two stages.The activation energyand and pre-exponential factor for the first stage was 179.03 k J/mol and 1017.91s-1 respectively.After the spheroidization,the TKX-50 sample was slightly higher in the decomposition temperature than before,and the activation energy was also larger and the thermal stability was better.The critical temperature and characteristic of TKX-50 thermal explosion after spheroidization were higher than those of raw materials,and the safety performance was better. |
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