Study On The Thermal Decomposition Of Molecular Perovskite Energetic Materials Catalyzed By Transition Metal Compounds

Molecular perovskites energetic materials have attracted more and more attention in recent years because of their excellent detonation and its simple synthesis process.For the amino perchlorate molecular perovskites energetic materials((H₂dabco)[NH₄(Cl O₄)₃],DAP-4),it could be regarded as the modification of ammonium perchlorate(AP),the most-commonly-used oxidizing component in solid propellants.And it is environmentally friendly,so it has further application prospect in solid propellant and explosives.In this paper,the thermal decomposition process of DAP-4 was studied.On this basis,the catalytic effect of MAX phase transition metal carbides(Mo₂Ti Al C₂),metal-organic framework materials(PB-s)and graphene-based transition metal oxides(Co₃O₄-r GO)on the thermal decomposition of DAP-4 was studied.Their possible catalytic mechanism are explored.The main findings of this paper are as follows:(1)The molecular perovskite energy-containing material DAP-4 was prepared by self-assembly method,and the thermal decomposition behavior of DAP-4 at different heating rates was studied by DSC.It was found that the heating rate had no significant effect on the thermal decomposition process of DAP-4,but with the heating rate increased,the exothermic peak of DAP-4 rose from 387.46°C to 410.62°C.Through the calculation of Kissinger and Ozawa methods,it is learned that the apparent activation energy of pure DAP-4 is 204.76KJ/mol and205.35KJ/mol respectively,and the apparent activation energy E_aof the two methods is highly consistent,indicating that the test results have a certain degree of credibility.(2)The structure of the MAX phase transition metal carbide Mo₂Ti Al C₂ was characterized by SEM and XRD,and the results showed that Mo₂Ti Al C₂ had a significant layered structure.The effect of Mo₂Ti Al C₂ on the thermal decomposition of DAP-4 was studied by DSC,the results show that at the heating rate of 10?/min,Mo₂Ti Al C₂ reduced the peak temperature of DAP-4 from 394.36?to 365.91?.According to Kissinger and Ozawa methods,the apparent activation energy of DAP-4/Mo₂Ti Al C₂ composite energetic material increases by more than46KJ/mol,74KJ/mol and 7KJ/mol,respectively,compared with pure DAP-4,showing better thermal stability.The possible mechanism of action of Mo₂Ti Al C₂ on DAP-4 was also discussed.(3)Prussian blue(PB-s)was prepared by using potassium ferricyanide and ferric chloride as raw materials.The structure of PB-s was characterized by SEM,XRD,XPS and FT-IR.The results show that the prepared PB-s is composed of cubic micro-spherical particles and its structure is stable.The effect of PB-s on the thermal decomposition of DAP-4 was studied by DSC,the results show that at the heating rate of 10?/min,PB-s reduced the peak temperature of DAP-4 from 394.36°C to 303.06°C.Compared with pure DAP-4,the apparent activation energy of DAP-4+1%PB-s and DAP-4+5%PB-s composite materials decreased by more than62KJ/mol and 66KJ/mol,respectively,according to Kissinger and Ozawa methods.However,the apparent activation energy of DAP-4+10%PB-s composite energetic materials increased by more than 21KJ/mol.The possible mechanism of action of PB-s on DAP-4 was also discussed.(4)Graphene-based transition metal oxides(CO₃O₄-r GO)were prepared from graphene oxide and cobalt nitrate as raw materials.The structure of Co₃O₄-r GO was characterized by SEM,XRD,XPS and FT-IR.The results confirmed that the self-made material was composed of disordered stacked flake graphene and well-crystallized Co₃O₄.The effect of PB-s on the thermal decomposition of DAP-4 was studied by DSC,the results show that at the heating rate of 10?/min,PB-s reduced the peak temperature of DAP-4 from 394.36°C to 342.30°C.According to Kissinger and Ozawa methods,compared with pure DAP-4,the apparent activation energy of DAP-4/Co₃O₄-r GO composites increased by more than 108KJ/mol after adding 1%Co₃O₄-r GO.However,when 5%and 10%Co₃O₄-r GO were added,the apparent activation energy of DAP-4/Co₃O₄-r GO composites decreased by more than 14KJ/mol and71KJ/mol,respectively.The possible mechanism of action of Co₃O₄-r GO on DAP-4 was also discussed.