Study On Preparation Of Graphene-based Nanocomposites And Their Catalytic Effect On TKX-50

As a new type of high-energy ionic salt,TKX-50?dihydroxylammonium 5,5'-bistetrazole-1,1'-diolate?has potential application prospects in the field of mixed explosives,especially in the field of propellants.It is a green energy-containing material that is expected to replace AP?ammonium perchlorate?as an important component of solid propellants.Graphene oxide?GO?has a special status in the field of graphene materials.It can be directly applied to energetic materials to form composite energetic materials,and it can also be used as a precursor to synthesize graphene-based composite materials and apply to in the field of catalysis of energetic materials.In this paper,GO was prepared,and TKX-50/GO composite energetic material was prepared from this material.Reduced graphene oxede?rGO?,Fe₃O₄nanoparticles and Fe₃O₄@rGO composites were prepared with GO and FeSO₄·7H₂O as precursors.Their structures and morphologies were characterized,and the catalytic effects of the three materials on the thermal decomposition of TKX-50 were tested.Firstly,GO was prepared by the traditional Hummers method,and the structure and morphology of GO were characterized by XRD,FTIR and SEM.The results showed that typical GO characteristic peaks appeared in the prepared samples,indicating that the target product was successfully prepared.GO presents a disordered layered structure,with clear layered folds visible on the surface and edges,indicating that a large number of oxygen-containing functional groups are introduced between the layers and edges of the GO sheet,which is also confirmed by infrared spectrum analysis.The thermal decomposition performance of GO was tested by TG-DSC.The results show that GO behaves as a two-stage weightless process,and the gaseous products of thermal decomposition are H₂O,CO,andCO₂.GO releases heat during thermal decomposition and can be regarded as an energetic material.Secondly,TKX-50/GO composite energetic material was prepared by spray freeze-drying method,and its structure,morphology and thermal decomposition properties were characterized.The results show that the TKX-50/GO composite energetic material prepared by the spray freeze-drying method has a nano-sized three-dimensional network structure,and the content of GO components is changed,which has a significant effect on the micromorphology of TKX-50/GO.The two exothermic peaks of TKX-50/GO composite energetic materials move to the low temperature direction,and the promotion effect of GO content on the low temperature exothermic peak of composite energetic materials remains within the range of 12.0¹2.5?,and the content of GO components increases The promotion effect of the high temperature exothermic peak moving to the low temperature direction is more significant until the two exothermic peaks overlap.Compared with TKX-50,the thermal decomposition reaction of TKX-50/GO composite energetic materials is more intense.Comparing the TG curves of the two,the weight loss of TKX-50/GO in the second stage of decomposition is advanced,and the quality of TKX-50 at 450?The loss was 96.81%,and the quality losses of TKX-50/GO₁,TKX-50/GO₃ and TKX-50/GO₅ were 94.68%,93.78%and 91.69%,respectively.The apparent activation energy of TKX-50/GO is more than 16kJ·mol^-1 higher than TKX-50,and it shows better thermal stability than TKX-50.Finally,the hydrothermal method and vacuum freeze-drying technology were used to prepare the rGO,Fe₃O₄ nanoparticles and Fe₃O₄@rGO nanocomposites.The structure and morphology of the nanocomposites were characterized.The catalytic effect of different contents on the thermal decomposition of TKX-50 was studied.The results show that the prepared rGO has a good three-dimensional structure.The diameter of Fe₃O₄ nanoparticles is20-50 nm but agglomeration occurs.Fe₃O₄ nanoparticles in Fe₃O₄@rGO nanocomposite are evenly dispersed on the rGO sheet,forming a good load.DSC test results show that the Fe₃O₄@rGO nanocomposite has the best catalytic effect on the thermal decomposition of TKX-50.The two-stage exothermic peak temperature of TKX-50 shifts up to 44.8?and48.6?towards the low temperature direction,and the apparent activation energy decreases.Above 11.3 kJ·mol^-1,Fe₃O₄@rGO nanocomposite can be a good additive for TKX-50-based solid propellants.