TKX-50 Crystal Surface Coating Modification And Performance Characterization

TKX-50（Dihydroxylammonium5,5’-bistetrazole-1,1’-diolate）is a new ionic energetic materials compound newly synthesized in recent years,which has outstanding features such as high detonation velocity（comparable to CL-20）,low sensitivities and good thermal stability,and has good application prospects,but its related formulations are still in the exploratory research stage.In this paper,in response to the problem that the mechanical properties of TKX-50-based PBX hybrid explosives are degraded due to the poor bonding strength of crystals and binder during preparation,theoretical and experimental studies on the surface coating modification of TKX-50 crystals were carried out to obtain two kinds of composite materials with core-shell structure,TKX-50@PDA and TKX-50@PANI,and their performance testing studies were conducted.The main research contents and results are as follows:（1）The BFDH method under the Morphology module of Materials studio software was used to predict the crystal morphology of TKX-50 under vacuum,and the main crystal surfaces were（011）,（020）,（100）,（110）and（11-1）.The bonding energy and mechanical properties of TKX-50 crystals with fluoroelastomers F₂₃₁₁,F₂₃₁₄ and F₂₆₀₂were simulated,and the bonding energy was ranked as F₂₆₀₂>F₂₃₁₁>F₂₃₁₄.Analysis of the moldability（K/G）and toughness（γ）of TKX-50/fluoroelastomer compound showed that several types of fluoroelastomers are suitable for covering TKX-50,and F2602 was selected as the binder for TKX-50 after a comprehensive trade-off.（2）The absorbance of the five oxidants dopamine-tris hydrochloride mixed solution was scanned by UV-Vis visible-UV spectrophotometer,and the absorbance of the solution with different reaction times at 420 nm for different specimens was tested using spectrophotometer,and the dopamine solution with the addition of Na IO4 had the fastest change in its absorbance and the best effect of promoting the polymerization reaction of dopamine.Dopamine can form a uniform and smooth PDA coating in the environment of O₂.（3）TKX-50@PDA-O₂ and TKX-50@PDA-Na IO₄composites were successfully prepared by water suspension method using PDA as the coating material,and the composites were tested and analyzed by SEM,XPS and FT-IR.the apparent activation energy of TKX-50@PDA-O₂and TKX-50@PDA-Na CIO₄decreased by 44.68 k J/mol and 50.97 k J/mol,and the impact and friction sensitivities were reduced.（4）Four composite energetic materials were successfully prepared by aqueous suspension using PANI as the capping material,and DSC showed that the activation energy of TKX-50@PANI-1 was 27.26 k J/mol lower than that of recrystallized TKX-50.The activation energies of TKX-50@PANI-2,TKX-50@PANI-3 and TKX-50@PANI-4 were increased by11.83 k J/mol,69.63 k J/mol and 50.87 k J/mol.The mechanical susceptibility and electrostatic spark susceptibility of the composites were reduced.