Song Zhang,Le-wu Zhan,Guang-kai Zhu,Yi-yi Teng,Yu Shan,Jing Hou,Li Bin-dong
Nano-TATB was developed in microchannels by physical method and chemical method, respectively. The effects of total flow rate, number of microreactor plates, solvent/non-solvent ratio and temperature on the particle size of TATB in the physical method were studied. Prepared TATB were characterized by Nano Sizer, Scanning Electron Microscopy, Specific surface aperture analyzer, X-ray diffraction, Fourier transform infrared spectroscopy and Differential Scanning Calorimetry. The results show that the TATB obtained by physical method and chemical method are spherical, with average particle size of 130.66 nm and 108.51 nm, respectively. Specific surface areas of TATB obtained by physical and chemical methods are 21.37 m 2 /g and 21.91 m 2 /g, respectively. Compared with the specific surface area of micro-TATB (0.0808 m 2 /g), the specific surface area of nano-TATB is significantly increased. DSC test results show that the smaller the particle size of TATB, the lower the thermal decomposition temperature. In addition, by simulating the mixing state of fluid in microchannels and combining with the classical nucleation theory, the mechanism of preparing nano-TATB by microchannels was proposed.
Passive micromixers are widely used in the preparation of ultrafine explosives because of their efficient mixing and necessary safety. A novel passive micromixer was designed to prepare nano-TATB. Computational fluid dynamics (CFD) is used to simulate the opening width (K), fluid velocity and mixing performance of the micromixer. The results show that the proposed micromixer has good mixing performance in the Reynolds number (Re) range of 0.1~100, and its pressure drop less than 28204 Pa at Re=100. A microfluidic recrystallization system was established and nano-TATB was prepared by a new micromixer. The results show that the average particle size of the prepared TATB is 93.12 nm, and the particle size distribution ranges from 43 nm to 151.4 nm. The SEM test shows that TATB has better morphological characteristics. XRD results show that the crystal structure of TATB is consistent with that of raw materials. This study proves that the new micromixer has good mixing effect and the feasibility of preparing nano TATB. It also provides reference for the design of micromixer and refinement of other energetic materials.