Carbon-coated Copper Nanoparticles Prepared By Detonation And Their Influence On Thermal Decomposition Of AP

In this paper,carbon-coated copper nanoparticles?CCNPs?were prepared successfully by detonation method.Thereinto,the detonation precursor was consisted of hexogen?RDX?which was acted as the main explosive,paraffin?WAX?acted as the carbon source and copper nitrate hydrate?Cu?NO₃?₂·3H₂O?acted as the metal source according to certain proportion.The influence of CCNPs on the thermal decomposition performance of AP and AP/HTPB based propellants was analyzed.Research results had certain practical guiding significance to the recycling of waste explosives.Firstly,the detonation parameters of detonation precursor with different ratio were simulated by EXPLO5,which was based on the explosive detonation theory.The effect laws of the ratio of RDX,WAX,Cu?NO₃?₂·3H₂O on the detonation temperature,explosion pressure and oxygen balance was obtained.Results indicated that detonation temperature and pressure decreased with the reduce of RDX content,and decreased with the increase of WAX and Cu?NO₃?₂·3H₂O.The negative oxygen balance increased significantly with the increase of WAX content,and the content of RDX and Cu?NO₃?₂·3H₂O had no significant effect on it.Based on the above results and the carbon / copper ratio of detonation products,four formulations as the detonation precursors were optimized.The four formulations were as follows: RDX0.7WAX0.2Cu?NO₃?₂·3H₂O0.1?2#?,RDX0.55WAX0.2Cu?NO₃?₂·3H₂O0.25?6#?,RDX0.5WAX0.15Cu?NO₃?₂·3H₂O0.35?8#?,RDX0.45WAX0.15Cu?NO₃?₂·3H₂O0.4?10#??Secondly,WAX/RDX coated particles were prepared by water suspension method with WAX which played a role as the coating material.The coated samples were mixed with Cu?NO₃?₂·3H₂O in a certain proportion and pressed into a explosive precursor with a certain density column.The explosive column was detonated with detonator in an explosive container,and the detonation products were collected after detonation.After pickling,washing and drying of the detonation products,the CCNPs were obtained.The composition and morphology of the detonation products were characterized by X-ray diffraction?XRD?,scanning electron microscope?SEM?,transmission electron microscopy?TEM?and Raman spectroscopy.Results indicated that the detonation products were spherical,25⁴5 nm in size,and had an apparent core-shell structure.In this structure,the carbon shell was 2⁵ nm thick and mainly composed of graphite and amorphous carbon.Finally,the CCNPs and AP were mixed evenly with a mass ratio of 5:95.The thermal decomposition performance of AP and AP/CCNPs mixture were analyzed using differential scanning calorimeter?DSC?.The thermal decomposition kinetic parameters of AP and CCNPs were calculated and analyzed.Results indicated the low-temperature decomposition peak of AP with CCNPs disappeared,the peak of high-temperature of AP with CCNPs decreased by 72.77?,72.93? and 74.77? at heating rates of 5,10 and 20°C/min respectively,and the apparent activation energy decreased by 27.18 kJ/mol calculated through Kissinger's method.In addition,the effect of CCNPs?3wt.%?on the thermal decomposition of AP/HTPB based propellant was investigated.Results indicated that compared with AP/HTPB based propellant formulations without CCNPs,the low-temperature decomposition peak of the formulations with CCNPs decreased by 58.74?,58.39? and 54.66?,the peak of high-temperature decreased by 33.59?,30.69? and 27.51? at heating rates of 5,10 and 20°C/min respectively,and the apparent activation energy decreased by 74.90 kJ/mol calculated through Kissinger's method.