Based on the classification of three commonly used azide polymers including glycidyl azide polymer, poly(3,3'-diazidomethyl epoxybutane), and poly(3-azidomethyl-3'-methyl epoxybutane), the synthesis process and modification method of azide binders are reviewed, and the future development of azide adhesives are looked forward:(1)based on the improvement of polymerization method and synthesis process, as well as the design and optimization of component and structure(introducing fluorine elements and utilizing chiral chemistry)of polymers, improving the energy and mechanical properties of azide binders;(2)developing new self-healing or easily healable azide binders;(3)developing nano-size azide binders to make each component in nano-size, enabling practical specific impulse closer to the ideal state. 121 References were attached.

To study the influence of silicon(Si)on 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane(CL-20), NC/CL-20 composite explosives and Si/NC/CL-20 composite explosives were prepared by the electrostatic spraying method. The morphology, structure and thermal decomposition properties of the samples were analyzed using scanning electron microscopy(SEM), X-ray energy spectroscopy(EDS), infrared spectroscopy(FT-IR), and simultaneous thermal analyzer(TG-DSC). Additionally, the combustion process of the samples was tested using a high-speed camera. The results show that the addition of nano-Si contributes to the formation of composite explosives with regular morphology and smaller particle size. The Si/NC/CL-20 composite explosive has better and more uniform sphericity, with an average particle size of 73.4nm, compared to the NC/CL-20 composite explosive. The Si/NC/CL-20 composite explosive which produced by the electrostatic spraying method, achieves physically uniform distribution of the components including NC, CL-20, Si. The addition of Si promotes the thermal decomposition of CL-20. In comparison to the NC/CL-20 composite explosive, the activation energy of the Si/NC/CL-20 composite explosive decreases by 16.78kJ/mol, and the self-accelerated decomposition temperature and the critical temperature of thermal explosion decreases by 3.12K and 2.61K, respectively. Furthermore, Si/NC/CL-20 composite explosive has shorter ignition delay time and faster combustion rate compared to the NC/CL-20 composite explosive, which shows that Si can improve the combustion performance of CL-20.

The dihydrazinium salt of 1,3-bis(5-tetrazolyl)triazene was synthesized via a diazotization/neutralization reaction using 5-aminotetrazole(5-ATz)as the starting material. On this basis, an energetic coordination polymer, [Zn₂(ATz)₃(CN)]_n(ECP-1), was prepared hydrothermally using zinc perchlorate. The crystal structure of ECP-1 was elucidated by single-crystal X-ray diffraction, and the thermal stability was studied by DSC and TG. The mechanical sensitivities of ECP-1 was tested and its detonation velocity and detonation pressure was calculated. Its catalytic performance in promoting the thermal decomposition of ammonium perchlorate(AP)was evaluated by DSC. The results show that the ECP-1 reveals a trigonal system with space group R32 and a high crystal density of 2.231g/cm³. It exhibits excellent thermal stability with a peak decomposition temperature of 391℃. The impact sensitivity and friction sensitivity are more than 40J and 360N,respectively. The detonation velocity and detonation pressure are 7.53km/s and 28.20GPa. The addition of 20% ECP-1 lowers the decomposition temperature of AP to 325.6℃ and reduced the activation energy by 34.27kJ/mol. These results highlight the promising catalytic capabilities of ECP-1 for AP decomposition, which shows potential utility as an energetic combustion catalyst.

To improve the morphology and particle size distribution and realize the controlled preparation of FOX-7 crystals, the micro-reaction technology was used to prepare refined FOX-7 by a modular microreactor. The effects of the microstructure disc size, solvent type, and the flux ratio of solvent-nonsolvent on the morphology and size distribution of the refined FOX-7 crystals were investigated and the optimal process conditions were determined. Scanning electron microscope(SEM)and particle size analysis software were used to characterize the morphology and particle size of the refined FOX-7 crystals. The structure and properties were studied by X-ray crystal diffraction(XRD), differential scanning calorimetry(DSC), thermogravimetric analysis(TG), BAM impact susceptibility meter and friction susceptibility meter. Results show that the FOX-7 crystals with a median particle size of d₅₀=1.23μm and a narrower particle size distribution(d₁₀=0.48μm, d₉₀=2.14μm)are obtained under the following conditions: the size of microstructure discs is 60×105μm(number×width), the solvent is NMP, and the flux ratio of solvent-nonsolvent is 1:10. There is no change in crystalline shape between the refined FOX-7 and the raw FOX-7. The critical temperature of thermal explosion of refined FOX-7 is increased by 18℃ compared with that of raw FOX-7. The impact energy is increased from 27.5J to 35J, and the friction energy is increased from 192N to 324N, indicating that the refined FOX-7 crystals have better thermal stability and lower mechanical sensitivity.

In order to accurately characterize the nonlinear mechanical behavior of polymer bonded explosive(PBX)during long-term creep loading and unloading process, the effectiveness of the classical models(power law model and Burgers model)from two kinds of traditional models in predicting creep unloading recovery performance was analyzed firstly by taking the PBX9502 explosive as an example. Based on the Boltzmann superposition principle, a nonlinear creep constitutive model dependent on loading history was proposed and extended to three-dimensional variable load form. Meanwhile,the stress update form and Jacobian matrix of the model were derived through discretizing it numerically. The nonlinear constitutive model was numerically implemented by compiling user-defined material subroutines, and the complete creep process and relaxation process of PBX were further simulated. The results show that two kinds of traditional viscoelastic-plastic models cannot predict the complete creep unloading recovery properties of PBX. However, the nonlinear creep constitutive model along with the numerical simulation method integrates the loading and unloading performance of PBX, and can describe a complete creep loading and unloading mechanical responses of PBX, which has potential in predicting the creep and relaxation properties of related materials under variable loads.

To obtain the evolution law of polymer bonded explosive(PBX)with high viscosity during the resonant acoustic mixing process, a high-efficiency resonant acoustic mixer, rotational rheometer, and differential scanning calorimeter were used to study the evolution law with mixing time of the morphologies, rheological properties, and safeties of NTO/HMX/Al based high-viscosity PBX in different process conditions. The results indicate that the material goes through four major stages during the resonant acoustic mixing: initial stage, spheronization stage, viscoelastic stage, and fluidization stage. As in the morphological evolution of high-viscosity PBX, the mode is determined by the container shape, while the difficulty is affected by the mixing temperature and acceleration. Additionally, altering the parameters to improve mixing efficiency can result in a quick decrease in the viscosity. In the spheronization stage, the temperature and electrostatic voltage of the material reach the peak. The thermal and mechanical safety of the material is relatively low, and the electrostatic safety decreases rapidly with the addition of the binder.

In response to the issues of the change in hydroxylammonium nitrate(HAN)concentration due to water evaporation during the reaction process, which leads to alteration of the activity as well as the inability to perform real-time online qualitative and quantitative analysis of reactants and products, a high-pressure continuous-flow fixed-bed reactor was designed to investigate the catalytic decomposition of HAN aqueous solutions over various alumina-supported noble metal catalysts with the real-time online mass spectrometry. It is found that the conversion of hydroxylammonium ions(NH₃OH⁺)is always greater than that of nitrate ones(NO^-₃)at the same temperature. And Pt-based catalysts exhibites the best activity, where the conversion rates of NH₃OH⁺ and NO^-₃ reach 100% and 45% at 120℃, respectively. At low temperatures(<100℃), NH₃OH⁺ is mainly converted to N₂O and NH⁺₄ with the selectivity of about 60% and 40% at 80℃, respectively, while NO^-₃ reacts with NH⁺₄ to produce N₂O as the temperature increases. The reactor designed in this work could provide the reference for studying the structure-activity relationship of catalysts and reaction mechanism.

In order to improve the interfacial bonding strength between the thermal insulation layer and the liner layer of solid rocket propellant, the surface of thermal insulation layer was processed by a femtosecond laser, and the microstructures were processed on the surface of the thermal insulation layer by the etching effect of the femtosecond laser. The microstructuresurface of the thermal insulation layer was characterized by a confocal laser microscope after the processing. The contact angle with water of the thermal insulation layer surface before and after processing were measured by a contact angle tester. The tear-off tests were conducted by complex environment test system to characterize the interfacial bonding strength of the thermal insulation layer before and after processing. The results show that the microstructure of the thermal insulation layer surface after femtosecond laser processing is uniformly distributed, and the morphology is homogeneous. The microstructure surface after processed greatly improves the wettability of the thermal insulation layer surface, and the contact angle with water is reduced from 94.6° to 27.7°. Compared with the unprocessed thermal insulation layer, the tensile strength after femtosecond laser processing was increased by 218% from 1.31MPa to 4.16MPa. The surface wettability and bonding strength of the thermal insulation layer was improved.

In order to study the effect of flow field characteristics on the breaking of solid propellant by cavitation water jet, HTPB propellant was taken as the research object, the numerical calculation of cavitation water jet at different nozzle expansion angles were carried out by using stress mixed eddy current model(SBES), and the influence mechanism of nozzle structure parameters on flow field characteristics were analyzed. The experimental study on HTPB propellant breaking by cavitation water jet were carried out, and the influence of flow field characteristics and breaking effect were discussed. The results show that the length of the potential flow core is affected by the expansion angle of the nozzle, which affects the velocity distribution on the target surface, and the propellant breaking depth is positively correlated with the velocity peak distribution on the target surface. The return jet at the nozzle outlet limits the development of cavitation towards the nozzle wall, thus affecting the cavitation intensity. The surface area of the breaking pit is positively correlated with the cavitation intensity, and is slightly smaller than the area covered by the cavitation cloud. The experimental results show that there is a great correlation between the flow field characteristics and the breaking results, which indicates that the flow field characteristics calculated by this method can be used to optimize and design the nozzle structure, improving the breaking efficiency of propellant. When the nozzle expansion angle is 60°, the cavitation water jet velocity and cavitation intensity have significant advantages. Combined with the analysis of breaking mass, breaking depth and breaking pit area, the breaking effect is the best at this time.

To enhance the analysis of experimental data in closed vessel tests, an iso-volumetric combustion model was established to numerically calculate the characteristics of pressure(p)—time(t). The fitting calculation was developed between the experimental test and the theoretical model, and the varying of burning rate could be solved for the high energy nitramine propellant. After that, different 7-perforated deterred high energy nitramine gun propellant samples were prepared, and the related equivalent parameters of iso-volumetric combustion model were fitted. It could quantitatively present the effects of deterring technology on the desensitizing layer, which referred to the decreasing of burning rate and the average thickness. The results show that, the static combustion characteristics of different gun propellant samples can be yielded by the iso-volumetric combustion model with the equivalent parameters. There are good agreements between the theoretical calculation and the experimental measurement. The equation of u=u₀+u_xpⁿ can conform to the relationship of burning rate(u)—pressure(p)for the high energy nitramine gun propellant. In the dry deterring technology, compared with the blank gun propellant, it can reach 72%—84% for the relative variation of equivalent burning rate of the deterring layer. Meanwhile, it locates in the level of O(10^-2)for the relative magnitude of average thickness between the deterring layer and the propellant web.