The Mechanism Of The Nano-TATB Self-assembled Growth Induced By Multi-factors

1,3,5-tramino-2,4,6-trinitrobenzene(TATB)is an insensitive heat-resistant energetic material with excellent stability and passivity.At present,TATB is still the only simple passivity explosive approved by the United States Department of Energy.Reducing the particle size of TATB explosive to micro or nano level can greatly improve its application performance.However,due to the anisotropy of the thermal expansion coefficient of TATB,the high proportion of molecules on the surface of nano-TATB and the low number of neighboring coordination of central molecules,nano-TATB energetic materials are more likely to be induced by a variety of environmental factors,such as temperature,humidity and microsolvent molecules,and the surface morphology and microstructure change,and the self-assembled growth phenomenon.The crystal properties of energetic materials are closely related to their surface morphology and microstructure.Changes in the surface morphology and microstructure of nano-TATB during long-term storage may lead to great differences in its macro performance and theoretical effect,which will affect its subsequent performance.This study takes this as a starting point,considering the induced effects of humidity,temperature,microsolvent molecules and their complex effects on the surface morphology and microstructure of nano-TATB during storage,and reveals the self-assembled growth mechanism of nano-TATB crystals induced by residual solvents during storage through solvent atmosphere induction method,so as to seek a more reasonable storage environment.In order to provide theoretical reference for the optimal storage method of energetic materials.Different temperature and humidity experiments were designed to investigate the influence of temperature,humidity and humidity combination on the evolution of micromorphology and structure of nano TATB during storage.It was found that the size and number of large crystal particles generated on the surface increased with the increase of storage time and relative humidity at room temperature,the specific surface area and porosity of nano-TATB decreased with time,indicating that agglomeration and fusion occurred among particles.For long-term storage,the combined effect of humidity and heat on nano-TATB is relatively large.However,the phenomenon of nano TATB selfaggregation and growth is relatively obvious under hot and humid conditions,which may also be due to the fact that nano TATB itself contains residual solvents,which jointly lead to the phenomenon of self-assembled growth under the stimulation of hygrothermal environment.In order to verify the effect of residual solvent on the self-aggregation and growth of nano-TATB,the microsolvent atmosphere was simulated by thermal solvent molecular induction method,and the influence of dimethyl sulfoxide(DMSO)as residual solvent on the surface morphology,microstructure,specific surface area,crystal structure,thermal stability and mechanical properties of nano-TATB during storage was explored.Mixing DMSO and ethanol according to a certain volume ratio to prepare mixed solvents with different solubility.It is found that the surface morphology and microstructure induced by different residual solvent molecules are related to the solubility of nanoTATB.The nano-TATB molecules on the surface layer became more reactive in the presence of DMSO and heating due to the intermolecular interaction and the capillary action of the DMSO adsorption solvent.Moreover,part of the TATB molecules dissolved in DMSO,resulting in the migration and rearrangement of nano-TATB molecules,which is the main reason for the self-assembly of nano-TATB.Ellipsometer TATB nanoparticles of about 100 nm were prepared by liquid nitrogen freezing method and deposited on silicon wafers as a substrate.The substrate and nanoTATB were sealed in the same environment,the sublimation-recrystallization deposition experiment was designed to investigate the effect of sublimation factors on the surface morphology and structure changes of nano TATB and crystal self-aggregation during storage.The results show that the sublimation-recrystallization mechanism at room temperature has little contribution to the surface morphology and structure changes of network structure nano-TATB and crystal self-assembled growth.Inspired by the phenomenon that nano-TATB are susceptible to the influence of residual solvents,the preparation of different particle sizes of TATB by hot-solvent atmosphere is proposed in this paper,which provides a reference for batch preparation of energetic material crystals with different particle size.