Study On Improving Safety And Thermal Decomposition Performance Of Ammonium Perchlorate Based On Insensitive Nano-explosive

The development of modern composite solid propellants with high safety,excellent thermal decomposition performance and green environmental protection is the development direction in the field of aerospace and weapons.However,the above performances are mutually restricted or even contradictory,making it difficult for the industry.As an oxidant,ammonium perchlorate(AP)is the most commonly used and the most important component in composite solid propellant.Its safety and thermal decomposition performance directly affect the various properties of solid propellant.In this paper,the high safety performance of insensitive nano explosive and its synergistic decomposition with AP greatly improves the safety and thermal decomposition performance of AP.At the same time,the decomposition products are all gas without heavy metal ions,so it is more environmentally friendly.The specific research contents are as follows:The effects of different types of explosives at the decomposition temperature from 210?to380?on the decomposition temperature of AP were investigated.Finally,1,3,5-Triamino-2,4,6-Trinitrobenzene(TATB),2,2',4,4',6,6'-Hexanitrostilbene(HNS),and 1-1,2,6-diamino-3,5-dinitro pyrazine-1-oxide(LLM-105)nano explosives were selected from the synergistic effect and safety performance.AP@TATB,AP@HNS and AP@LLM-105 core-shell composites with different mass ratios were successfully prepared by ultrasonic synthesis.XRD analysis showed that Estane,TATB,HNS and LLM-105 did not affect the crystal form of AP.Combined with XPS and SEM analysis,in a certain range,the higher the mass ratio of nano explosives,the better the coating degree.For example,when the content of nano-TATB is 5 wt%,nano-TATB appears on the surface of AP,but it fails to form a complete shell.With the increase of TATB content to 10 wt%,the surface of AP is completely covered by TATB,forming a complete core-shell structure.Similarly,XPS and SEM characterization showed that the AP@HNS and AP@LLM-105 core-shell composites prepared with 15 wt%mass fraction of HNS and LLM-105 respectively had complete and dense shell.The thermal decomposition performance and activation energy of AP@TATB composites were analyzed according to DSC technology.The high-temperature decomposition peak of AP@TATB composites could be advanced to 365.3?by 10 wt%shell TATB,the apparent heat release was increased to 1171.6 J/g,and the activation energy was reduced to 124.7 k J/mol.When the mass fraction of shell HNS was 15 wt%,the decomposition temperature of AP@HNS composite decreased to 319.9?,the heat release was 1064 J/g,and the activation energy was 163.5 k J/mol;When the content of LLM-105 shell was 15 wt%,the high-temperature decomposition peak and low-temperature decomposition peak of AP@LLM-105 composite overlapped at 296.4?,the apparent heat release was 1271 J/g,and the activation energy was reduced to 154.6 k J/mol.The gas products during the decomposition of the three complexes were analyzed by STA-FTIR.It was speculated that HCl O₄produced by AP decomposition promoted the decomposition of explosives,and NO₂released by explosive decomposition oxidized HN₃,thus leading to the advance of high temperature decomposition temperature.In the mechanical sensitivity test,the impact sensitivity H₅₀of AP@TATB composite is more than 90 cm,and the friction sensitivity P is reduced to 0.The impact sensitivity H₅₀of AP@HNS composite is 32 cm,and the friction sensitivity P is 77%.The impact sensitivity H₅₀of AP@LLM-105 decreased to 39 cm and the friction sensitivity P decreased to 18%.In summary,AP@nano-explosive composite was designed and prepared in this paper,which greatly improved the safety performance of AP through the buffering and blocking effect of insensitive nano-explosive on the shell.Through the synergistic decomposition of explosives,the thermal decomposition performance of AP was improved.The decomposition products are all gas,and there is no heavy metal ion component used in the thermal decomposition of AP,so it is more environmentally friendly.At the same time,the heat generated by the decomposition of explosives improves the energy of AP.Therefore,the research results in this paper are expected to provide technical support for new solid propellants with high safety,excellent thermal decomposition performance and environmental protection.