By combination of the transient Raman spectroscopic measurement and the density functional theoretical calculations,the structural evolution and stability of TATB under shock compression was investigated.Due to the im...By combination of the transient Raman spectroscopic measurement and the density functional theoretical calculations,the structural evolution and stability of TATB under shock compression was investigated.Due to the improvement in synchronization control between two-stage light gas gun and the transient Raman spectra acquisition,as well as the sample preparation,the Raman peak of the N-O mode of TATB was firstly observed under shock pressure up to 13.6 GPa,noticeably higher than the upper limit of 8.5 GPa reported in available literatures.By taking into account of the continuous shift of the main peak and other observed Raman peaks,we did not distinguish any structural transition or any new species.Moreover,both the present Raman spectra and the time-resolved radiation of TATB during shock loading showed that TATB exhibits higher chemical stability than previous declaration.To reveal the detailed structural response and evolution of TATB under compression,the density functional theoretical calculations were conducted,and it was found that the pressure make N-O bond lengths shorter,nitro bond angles larger,and intermolecular and intra-molecular hydrogen bond interactions enhanced.The observed red shift of Raman peak was ascribed to the abnormal enhancement of H-bound effect on the scissor vibration mode of the nitro group.展开更多
Polymer bonded explosives(PBXs)have high energy density,excellent mechanical properties and better thermal stability.In this study,droplet microfluidic technology was used to successfully prepare HMX/TATB microspheres...Polymer bonded explosives(PBXs)have high energy density,excellent mechanical properties and better thermal stability.In this study,droplet microfluidic technology was used to successfully prepare HMX/TATB microspheres.The effects of different binder types and binder concentrations on the morphology of the microspheres were studied,and results proved that NC/GAP(1:4)provides particles a regular spherical morphology and good dispersion.Subsequently,the influence of the concentration of the dispersed phase and the flow rate of the continuous phase on the particle size distribution of the microspheres was fully studied.The microspheres had narrow particle size distribution and high spherical shape.Under optimized process conditions,HMX/TATB microspheres were prepared and compared with the physical mixtures.The X-ray diffraction,differential scanning calorimetry,flow properties,bulk density,and mechanical sensitivity of the samples were also studied.Results showed that the crystal form of the microspheres remains unchanged,and the binder maintains good compatibility with explosives.In addition,the fluidity,bulk density,real density and safety performance of the microspheres are remarkably better than the physical mixture.This study provides a new method for preparing PBX with narrow particle size distribution,high spherical shape,excellent dispersion and high bulk density.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.12072299,11902276)the Natural Science Foundation of Sichuan Province(Grant No.2022NSFSC1802)+1 种基金the Basic Research Project of Southwest Jiaotong University(Grant No.2682023ZTPY009)the National Key Laboratory for Shock Wave and Detonation Physics of China(Grant No.JCKYS2019212007)。
文摘By combination of the transient Raman spectroscopic measurement and the density functional theoretical calculations,the structural evolution and stability of TATB under shock compression was investigated.Due to the improvement in synchronization control between two-stage light gas gun and the transient Raman spectra acquisition,as well as the sample preparation,the Raman peak of the N-O mode of TATB was firstly observed under shock pressure up to 13.6 GPa,noticeably higher than the upper limit of 8.5 GPa reported in available literatures.By taking into account of the continuous shift of the main peak and other observed Raman peaks,we did not distinguish any structural transition or any new species.Moreover,both the present Raman spectra and the time-resolved radiation of TATB during shock loading showed that TATB exhibits higher chemical stability than previous declaration.To reveal the detailed structural response and evolution of TATB under compression,the density functional theoretical calculations were conducted,and it was found that the pressure make N-O bond lengths shorter,nitro bond angles larger,and intermolecular and intra-molecular hydrogen bond interactions enhanced.The observed red shift of Raman peak was ascribed to the abnormal enhancement of H-bound effect on the scissor vibration mode of the nitro group.
基金supported by the National Natural Science Foundation of China(No.22005275)Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi(STIP,No.2019L0584)the Advantage Disciplines Climbing Plan of Shanxi Province.
文摘Polymer bonded explosives(PBXs)have high energy density,excellent mechanical properties and better thermal stability.In this study,droplet microfluidic technology was used to successfully prepare HMX/TATB microspheres.The effects of different binder types and binder concentrations on the morphology of the microspheres were studied,and results proved that NC/GAP(1:4)provides particles a regular spherical morphology and good dispersion.Subsequently,the influence of the concentration of the dispersed phase and the flow rate of the continuous phase on the particle size distribution of the microspheres was fully studied.The microspheres had narrow particle size distribution and high spherical shape.Under optimized process conditions,HMX/TATB microspheres were prepared and compared with the physical mixtures.The X-ray diffraction,differential scanning calorimetry,flow properties,bulk density,and mechanical sensitivity of the samples were also studied.Results showed that the crystal form of the microspheres remains unchanged,and the binder maintains good compatibility with explosives.In addition,the fluidity,bulk density,real density and safety performance of the microspheres are remarkably better than the physical mixture.This study provides a new method for preparing PBX with narrow particle size distribution,high spherical shape,excellent dispersion and high bulk density.
