Preparation And Thermodynamic Properties Of Graphene Oxide-based Novel Energetic Composites

With the wide application of millimeter wave radar in the military field,the dynamic whereabouts of weapons and equipment,individual combat and infantry are threatened more and more.Smoke passive jamming technology has become one of the most effective ways to combat millimeter wave radar because of its good millimeter wave jamming ability,efficient and maneuverable dynamic masking advantages.Carbon based materials represented by graphene oxide and carbon fiber are one of the smoke interference materials widely studied and used at present.However,the current carbon based smoke interference materials generally have some shortcomings,such as poor thermal decomposition activity caused by high activation energy and enthalpy,low decomposition sensitivity caused by high decomposition peak temperature,small explosion divergence area and short effective suspension time caused by low energy content of smoke materials,which are difficult to meet the needs of weapons and armaments dynamic stealth requirements in military fields such as individual combat and infantry marching.In view of the above problems,in this paper,glycidyl azide polymer(GAP)and 3,3-bisazide methyloxybutylene tetrahydrofuran copolymer(BAMO-THF)were used as binding additives for energetic materials,and chopped carbon fiber(CF)was used as millimeter wave interference agent and crosslinking agent to modify graphene oxide(GO)by solution dispersion based blending,two new energetic smoke passive interference composites,GO/GAP/CF and GO/BAMO-THF/CF,were prepared respectively.The microstructure and thermal decomposition properties of the composites were characterized by scanning electron microscopy(SEM),X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FT-IR)and differential thermal analyzer(DSC).SEM shows that due to the crosslinking effect of CF,the two composites have eliminated pores and gaps compared with the original GO and become a continuous network structure.At the same time,GO has a coating effect on CF.SEM test results also show that due to the network porous structure of BAMO-THF,GO/BAMO-THF/CF has better coating effect and continuous fold structure than GO/GAP/CF,and its energy density is further higher than GO/GAP/CF.FT-IR and XRD show that the composites contain azide groups and azide based amorphous diffraction peaks,which proves that GAP,BAMO-THF and GO are well combined,and the diffraction angle of GO crystal diffraction peak of GO/BAMO-THF/CF shifts to a high angle relative to GO/GAP/CF,which also proves its better crosslinking effect.DSC results showed that compared with the original GO,the activation energy and enthalpy of GO/GAP/CF decreased by 57.6 KJ/mol(About24 %),the free energy decreased by 1.2 KJ/mol(0.86 %),and the average heat release rate increased by about 10.42 %;The activation energy and activation enthalpy of GO/BAMO-THF/CF are reduced by 95.8 KJ/mol(About 40 %),the free energy is reduced by16.9 KJ/mol(12.11 %),and the average heat release rate is increased by about 32.84 %,indicating that the thermal decomposition activity of the two composites is improved and have higher energy density.Due to the network porous structure,self height decomposition promotion rate and high reaction heat of BAMO-THF(Up to 1185 J/g),GO/BAMO-THF/CF has better coating effect than GO/GAP/CF,The energy released by thermal decomposition can be quickly transferred to the whole material,so it has the best thermodynamic performance.Because the two composites contain 15-20 % CF and GO,and the content is only about 70 %,there is little change in decomposition weight loss.At the same time,the experimental data show that the exothermic peak temperature and weight loss performance of GO/BAMO-THF/CF are less improved than GO/GAP/CF,which is due to the lower exothermic interval start temperature of GAP(210.5 ?)and higher weight loss ratio(Weight loss at 400 ?)of GO/BAMO-THF/CF.Finally,through Fluent software and Origin software,the movement change law of smoke particle fluid impact pressure with time and smoke particle coverage after 0.05 s are simulated,analyzed and data fitted.The simulation results show that the smoke screen materials basically meet the requirements of military applications for the suspension time of smoke interference materials.At the same time,compared with the current smoke screen materials of graphene or carbon fiber composite metals and their oxides,the two composites also have the advantages of low density and low preparation cost,which shows their great potential application value in the field of millimeter wave smoke interference in military applications,It can also provide reference for the preparation and research of new energetic millimeter wave smoke passive interference carbon matrix composites in the future.