Performance Of Nano-cocrystal Nitroamine Explosives Fabricated By Mechanical Milling Method

At present,"nanocrystallization"and"cocrystallization"can effectively reduce the sensitivity of high-energy explosives and improve their safety and practicality.In this dissertation,three kinds of nano-cocrystal nitroamine explosives were prepared by mechanical milling method which can achieve nanocrystallization and cocrystallization simultaneously.On this basis,the crystal structure,micro-morphology,sensitivity and performance of nano-cocrystal nitroamine explosives were studied.The main research contents are as follows.The structures of CL-20/HMX,CL-20/RDX and HMX/RDX were optimized and calculated at the DFT-B3LYP/3-21+G*level using Gaussian09.The results show that the cocrystal explosives form C-H…O hydrogen bonds with bond lengths ranging from 1.978?to 2.645?.The structures of the maximum intermolecular interaction energy(?E_max)are:CL-20/HMX structure III(33.196 kJ·mol^-1),CL-20/RDX structure IV(18.541 kJ·mol^-1),HMX/RDX structure III(41.756 kJ·mol^-1).Three kinds of nano-cocrystal nitroamine explosives?CL-20/HMX,CL-20/RDX and HMX/RDX?were prepared by mechanical milling method.The analysis of SEM,TEM,XRD,Raman,IR and EDS showed that these cocrystal explosive particles were near-spherical,with mean particle size of 81.6 nm,141.6 nm,and 250.1 nm,respectively.Diffraction peaks of the new phase appear in the crystals of the cocrystal explosive,and vibration absorption peaks of-NO₂ and-CH₂ shift or disappear because of the formation C-H…O hydrogen bonds.The explosives contain only four elements of C,H,O,and N.Sensitivity and performances of nano-cocrystal explosives were tested by DSC,DSC-IR and sensitivity tests.Compared with the raw materials,the results showed that the thermal decomposition peak temperature?T_p?of the nano CL-20/HMX cocrystal decreased by approximately 3.2°C and 53.9°C,respectively,and the special height(H₅₀)decreased by17.62 cm and 5.48 cm,respectively,and the percentage of friction explosion?P?decreased by32%and 19%,respectively,and the 5s boost point(T_5s)decreased by 27.11°C and 56.91°C,respectively.The T_p of the nano-CL-20/RDX cocrystal decreased by 13.7°C and 19.3°C,respectively,and the H₅₀0 decreased by 36.43 cm and 9.78 cm,respectively,P decreased by44%and 18%,respectively,and T_5ss decreased by 40.06°C and 57.69°C,respectively.The nano-HMX/RDX cocrystal had a T_p value of 261.9°C,H₅₀0 decreased by 17.83 cm and 3.32cm,P decreased by 17%and 4%,and T_5ss decreased by 16.98°C and 4.81°C,respectively.Thermal decomposition products of nano-cocrystal nitroamine explosives contain large amounts of CO₂ and nitrogen oxides.