In Situ Preparation And Properties Of MgWo₄-GO And Cu-Co/GO Composites

Solid propellant is the main power source of rocket and missile engines.Exploring and researching a kind of high-energy,stunned solid propellant with good application performance is the current research focus of national military industry development.Among them,combustion catalyst as the main regulator of propellant combustion performance,to a large extent determines the combustion performance of solid propellant.In situ growth is realized by grafting oxygen-containing functional groups on the surface of graphene oxide?GO?with metal ions.This is a new method to synthesize graphene oxide based composite materials after physical mixing and self-assembly methods.Compared with the other two methods,the nanocomposite synthesized by this method can be used as a combustion catalyst for solid propellants.On the one hand,it can reduce the agglomeration of the nanoparticles,and on the other hand,it can significantly enhance the bonding strength between composite materials,solve the separation problem in liquid propellants,and greatly enhance their thermal decomposition catalytic performance.In this paper,two kinds of Mg WO₄-GO and Cu-Co/GO composites were prepared by in situ growth method,and their structure,morphology,catalytic decomposition performance and thermal decomposition kinetic equation were studied in detail.The specific research contents are as follows:1.Mg WO₄ adopted ethylene glycol?EG?and water as solvents was synthesized by one-step solvothermal method at different solvent ratios?EG:Water=7:0,6:1,5:2,4:3,3:4,2:5,1:6 and 0:7?.XRD and SEM results showed that two different crystal forms and eight different morphologies of Mg WO₄ particles were obtained.The research on the catalytic decomposition of AP shows that when the ratio of EG:Water is 7:0,that is,the Mg WO₄obtained in the pure EG solvent has the best catalytic decomposition performance,which can reduce the low temperature decomposition of AP from 310 to 298?,the high temperature decomposition was reduced from 405 to 371?.This is mainly due to the smaller particle size and larger specific surface area of Mg WO₄ prepared in pure EG solvent.2.Graphene oxide?GO?used in this experiment was prepared using modified Hummers.Mg WO₄-GO nanocomposite was prepared by in situ growth-assisted solvothermal method using three different dispersants?urea,polyethylene glycol and PVP?.The ultrasonic dispersion results show that the Mg WO₄-GO composite prepared by the in situ growth method is more stable,compared with self-assembled Mg WO₄/GO,and it is not easy to disperse in water by ultrasound.The catalytic decomposition experiments of HMX,RDX and AP show that Mg WO₄-GO prepared with urea as a dispersant has a smaller particle size and therefore having the best catalytic performance,which makes the exothermic decomposition temperature of HMX,RDX and AP decrease by 15.06,11.09 and 66.60?,respectively,the apparent activation energy of RDX reduce by 68.60 k J·mol^-1.Finally,the catalytic decomposition mechanism of AP was studied in depth.3.Cu Co₂O₄-GO composites were prepared by in situ growth methods.XRD and SEM results showed that spherical particles with regular morphology and uniform size were obtained.However,it was not the Cu Co₂O₄-GO composite by standard card matching.For this reason,three different calcination atmospheres?Air,N₂ and Ar?were used for high-temperature calcination at 500?for 5 h.XRD results showed that Cu Co₂O₄,Cu O and Co O,Cu and Co elemental substances were formed after calcination in Air,N₂ and Ar atmospheres.The GO contained in the composite material was completely decomposed after being calcined in Air atmosphere,and carbon deposition was formed due to incomplete decomposition after calcination in N₂ and Ar atmospheres.Finally,the catalytic performance of the samples before and after calcination on RDX and RDX+NC was studied.The research results show that the Cu-Co/GO?Ar?composite calcined in Ar atmosphere has the best catalytic effect on RDX and RDX+NC.This is mainly due to its smaller particle size,good crystallinity after Ar calcination,and the"synergistic effect"between the Cu,Co and carbon materials.