Abstract:In order to solve the problems of high temperature and high pressure in the synthesis of 1-methyl-3，4， 5-trinitropyrazole （MTNP）， a new method of simple synthesis of MTNP was developed， that is， 4-chlorpyrazole （1） was used as raw material， and MTNP was synthesized by nitration， N-methylation， benzylamine amination and oxidation. The effects of material ratios， temperatures， solvents， debenzylation reagents， and oxidation conditions on the yields of 4-benzylamino-1-methyl-3，5-dinitropyrazole （4）， 4-amino-1-methyl-3，5-dinitropyrazole （5）， and MTNP were investigated. Fourier transform infrared spectroscopy （FT-IR）， nuclear magnetic resonance （NMR） and high performance liquid chromatography （HPLC） were used to characterize the structures of the intermediates and target compounds. The results showed that when the intermediate 4 was synthesized， the molar ratio of n（benzylamine）：n（4-chloro-1-methyl-3，5-dinitropyrazole， 3）=6∶1， the reaction temperature was 35 ℃， and petroleum ether/water was the solvent， the yield was 89.6%. In the synthesis of intermediate 5， concentrated sulfuric acid （98%） was used as debenzyl reagent， and the yield was 95.2%. The yield of MTNP was 60.5% by using intermediate 4 as substrate and “one-pot method” of debenzylation/oxidation. By optimizing the reaction conditions， the total yield of MTNP synthesized from raw material 1 by one-pot method was 41.5% and the purity was 98% （area normalization method）.

Abstract:To develop efficient Burning rate catalyst （BRC）， a key component for regulating solid propellant combustion performance， and to explore the role of single-atom catalysts， a Fe single-atom catalyst supported on porous carbon carrier （Fe-NC@PC） was designed and synthesized. The composition and morphology were thoroughly characterized by X-ray powder diffractometer （XRD）， X-ray photoelectron spectroscopy （XPS）， scanning electron microscope （SEM）， transmission electron microscope （TEM）， high-angle annular dark-field scanning transmission electron microscope（HADDF-STEM） and X-ray absorption fine structure （XAFS）. Moreover， the effect of Fe-NC@PC on thermal decomposition for energetic materials within solid propellant was investigated via thermogravimetric-differential scanning calorimetry （TG-DSC）. Results show that Fe atoms in Fe-NC@PC were anchored on the carrier surface via Fe-N bonds with the loading amount of 0.98%. Upon the addition of 5% Fe-NC@PC， the thermal decomposition peak temperature of 1，1-diamino-2，2-dinitroethylene （FOX-7）， cyclo-1，3，5，7-tetramethylene-2，4，6，8-tetranitramine （HMX）， hexanitrohexaazaisowurtzitane （CL-20） and Dihydroxylammonium 5，5’-bistetrazole-1，1′-diolate （TKX-50） decreased by 34.6， 9.4， 6.3 ℃ and 27.9 ℃， respectively， demonstrating clear catalytic effects. Additionally， the apparent activation energies were also altered.

Abstract:To address the low energy release efficiency of aluminum powder as a metallic fuel， aluminum-based composite fuels containing 3%-6% polyvinylidene fluoride （PVDF） were prepared using mechanical alloying. The powders were characterized using scanning electron microscopy （SEM） and X-ray diffraction （XRD） to analyze their microstructures and phase compositions. The active aluminum content was measured by gas volumetric analysis， and the combustion calorific values were determined using oxygen bomb calorimetry. Thermal oxidation properties were evaluated through thermogravimetric-differential scanning calorimetry （TG-DSC） and a custom-built rapid heating oxidation setup. SEM and XRD results revealed that the composite aluminum powder modified with 4% PVDF dispersion prevented the formation of a continuous Al₂O₃ shell during heating. TG-DSC analysis showed a 76.7% oxidation weight gain at 1300 ℃ for the composite powder， representing a 35.8% improvement over pure aluminum powder （40.9%）. Rapid oxidation tests at 1100 ℃ demonstrated a 64.6% weight gain after 120 s for the composite powder， which is 41.2% higher than the 23.4% weight gain of pure aluminum. These findings highlight the critical role of PVDF dispersion modification in enhancing the oxidation activity and efficiency of aluminum powder.

Abstract:In order to investigate the effects of a new energetic photocurable binder terminal acrylate based poly（3-nitratomethyl-3-methyloxetane） （APNIMMO）， on the thermal decomposition and combustion properties of RDX-based photocurable gun propellants， a high-energy APNIMMO/RDX gun propellant sample was designed and fabricated by 3D printing. The thermal decomposition process and related kinetic parameters of the APNIMMO/RDX photocurable gun propellant were studied using differential scanning calorimetry （DSC） and thermogravimetry-differential scanning calorimetry-Fourier transform infrared spectroscopy-gas chromatography （TG-DSC-FTIR-GC）. The combustion performance of the APNIMMO/RDX photocurable gun propellant was evaluated using a closed bomb tester. The results indicate that the thermal weight loss of the APNIMMO/RDX photocurable gun propellant occurs in two main stages. Thermogravimetry and gas product escape mainly focus on the first stage（158.9-234.3 ℃）， In this stage， tthe thermal decomposition of APNIMMO/RDX begins with the exothermic decomposition of APNIMMO， promoting the melting and decomposition of RDX. This causes RDX to decompose earlier， leading to a lower critical explosion temperature （T_pe） for APNIMMO/RDX compared to pure RDX. The second stage （234.3 ℃ to the end of the test） presents a “thermal neutral” state with neither exothermic nor endothermic behavior， mainly attributed to the slow decomposition of the APNIMMO backbone after the complete decomposition of its side-chain nitrate ester groups. The results of combustion performance show that the burning rate coefficient of APNIMMO/RDX propellant is low， the pressure index is high， and there are a large number of holes on the surface of the sample of the aborting combustion test. The analysis shows that in the APNIMMO/RDX propellant system， the burning rate of RDX is higher than that of APNIMMO binder under high pressure due to the large content of RDX. The difference in burning rate between the two causes the heat and pressure generated by combustion to penetrate into the entire propellant along the formed holes， and the process is greatly affected by pressure， so the pressure index is high.

Abstract:In order to investigate the reaction characteristics of oxidizer-fuel composite materials with different particle sizes in constant-volume combustion， laser ignition and detonation environment of high energy explosive hexanitrohexaazaisowurtzitane （CL-20）， three particle sizes of perfluoropolyether-functionalized micro/nano aluminum （nAl_150@xPFPE， μAl_1@xPFPE and μAl_5@xPFPE， where x=2.5%， 5.0%， 7.5%） was constructed by particle suspension method， and CL-20 based aluminized explosive was prepared by kneading granulation method. The pressure-time curve， laser-induced ignition process， energy release rate and efficiency of samples in CL-20 were studied by means of closed constant-volume explosive device， laser ignition， detonation velocity and detonation heat test equipment， respectively. The results showed that with the increase of PFPE mass fraction， the peak pressure and pressurization rate of nAl_150@xPFPE samples and μAl_1@xPFPE samples increased gradually， while the peak pressure of μAl_1@7.5%PFPE sample reached 4138.4 kPa and its pressurization rate reached 0.216 MPa·ms^-1. However， when the PFPE mass fraction exceeded 5.0%， the pressurization rate seemed to slow down. At the same time， with the increase of PFPE mass fraction， the burning rate of PFPE-functionalized micro/nano aluminum in CL-20 increased gradually. When x=7.5%， the burning rate of all the three samples with different particle sizes in CL-20 increased by 2.1 cm·s^-1， 1.8 cm·s^-1 and 2.3 cm·s^-1， respectively. In addition， four kinds of fuel-rich CL-20 based aluminized explosives were designed. Among them， the measured detonation velocity of JWL-3 explosive （62% CL-20/32% μAl_1@5.0%PFPE/6% binder） was 8125 m·s^-1， the measured detonation heat was 8049.8 kJ·kg^-1， and the energy release efficiency reached 86.10% （measured by detonation heat）.

Abstract:Understanding thecorrelations between solid propellant composition， burning rate characteristics， and safety parameters including the impact， friction， and electrostatic spark sensitivities for both HTPB （Hydroxyl-Terminated Polybutadiene） propellant slurry and its final cured product is crucial for optimizing both the safety profile and performance characteristics of solid composite propellants. This study systematically applies the grey relational analysis method to quantitatively evaluate the relationships between formulation parameters（aluminum content， ammonium perchlorate content， RDX proportion and the total solid loading in the overall mass） and burn rate with the safety parameters measured for both HTPB propellant slurry and its final product. The key influencing factors for each sensitivity parameter were identified. The results indicate that ammonium perchlorate content exhibits the strongest correlation with both impact and electrostatic spark sensitivities in HTPB propellant slurry， while RDX content displays the predominant influence on friction sensitivity. Regarding the sensitivity of the final cured product， aluminum content emerges as the dominant factor influencing impact sensitivity， whereas burning rate and solid content become the primary determinants affecting the friction and electrostatic spark sensitivity， respectively.

Abstract:To further improve the accuracy of the Virial-Peng-Long （VPL） equation of state （EOS） in describing the thermochemical relations of gaseous detonation products， and to enhance the accuracy of the VPL EOS in predicting the detonation performance of energetic materials， the abnormal inflection points in the short-range repulsive stage were corrected based on the analysis of the mathematical form of Exponential-6 （Exp-6） potential to obtain a novel exponential molecular potential： Exponential-6modified （Exp-6m） with the globally continuous and smooth potential function curve. On this basis， a high-order virial type gaseous detonation product EOS： Virial-Peng-Long modified （VPLm） EOS was established based on the theoretical values of 2-5th virial coefficients of Exp-6m potential. On one hand， the detonation Chapmann Jouguet （C-J） parameters of oxygen rich equilibrium explosives such as PETN and NG， as well as high-energy density explosives such as CL-20， were calculated using the VPLm EOS. The results show that VPLm EOS can accurately evaluate the detonation performance for explosives. The prediction deviation of detonation C-J pressure of PETN at higher densities less than 1.5%， and the prediction deviation of detonation velocity of high-density CL-20 can also be controlled within 1.6%. The calculation accuracy has been significantly improved compared to the VPL EOS. On the other hand， VPLm EOS was applied to calculate the detonation velocity of typical metal-containing primary explosive， lead azide （LA）， at different densities. The results show that the VPLm EOS had better accuracy in predicting the detonation velocity of LA than Explo5 and CHEETAH， and can more accurately evaluate the detonation velocity of LA at higher densities compared to the VPL EOS.

Abstract:To overcome the limitations of conventional cook-off models in full-chain prediction of explosive formulations and charge behaviors while eliminating post-ignition temperature field singularities， a multi-component parameter fitting model was systematically applied to investigate the thermal decomposition response and cook-off characteristics of polymer-bonded explosives （PBX-9501， PBX-9502， and novel PBX-4）. A component parameter-driven full-process simulation framework was established through coupled multi-physics modeling integrating Arrhenius reaction kinetics with the JWL product gas equation of state， enabling numerical characterization from initial thermal decomposition to final casing rupture. Validation results demonstrated that ignition time prediction errors for PBX-9501 and PBX-9502 were 3.4% and 5.7% respectively compared with experimental data. Ignition time deviation for PBX-4 prediction reached 2.3% against validation experiments. Dynamic regulation of product gas parameters stabilized explosion temperatures within 3328-3502 K， effectively resolving temperature singularity issues inherent in traditional solid-phase cook-off models.

Abstract:The process parameters have a direct impact on the 3D printing quality of solid propellant grains. To more reasonably adjust the 3D printing process parameters and improve printing quality， based on the single-layer stacking process， a numerical simulation method was employed to conduct an orthogonal experimental study on three influencing factors： extrusion speed， printing height， and printing temperature. The degree of influence of each factor was calculated through variance and range analysis. The grey relational analysis method was adopted for comparison， and the optimal combination of process parameters was selected after comprehensively considering the printing accuracy of special points. A method for calculating the printing line spacing based on single-line cross-sectional data was proposed for the first time， and simulation and experimental verification were conducted. The results indicated that the extrusion speed had the greatest impact on printing quality. When the extrusion speed was set to 12 mm·s^-1， the nozzle height was 1.2 mm， and the printing temperature was 55 ℃， the printed part exhibited optimal quality. After parameter adjustment， the tensile strength of the specimen increased from 0.21 MPa to 0.43 MPa， and the density rose from 1.43×10³ kg·m^-³ to 1.65×10³ kg·m^-³. Single-layer printing simulations and experiments demonstrated a significant improvement in molding quality after parameter adjustment.

Abstract:3-Nitro-1，2，4-triazole-5-one （NTO） is a typical insensitive energetic material that combines low sensitivity， high energy density， and a simple manufacturing process. In recent years， it has attracted significant attention from researchers. The crystallization characteristics of NTO， including crystal morphology and particle size， are critical factors in its production and application， directly influencing its flowability， bulk density， formulation safety， and detonation performance.This study presents a systematic review of recent advancements in NTO crystallization and modification technologies， covering aspects such as crystallization fundamentals， particle size and morphology control， cocrystal formation， and coating techniques. Particular emphasis is placed on the thermodynamic and kinetic properties of NTO crystallization in commonly used solvents， as well as the application of spherulization techniques. Furthermore， the study highlights effective strategies for simultaneously enhancing both energy performance and safety through cocrystal and coating approaches.It is recommended that future research efforts further explore or strengthen green crystallization techniques based on aqueous systems， the preparation of spherical single crystals， crystallizer design， and flow field simulations. These advancements will facilitate precise control of crystallization processes in industrial production and accelerate the development of multi-specification NTO crystal products tailored to various application scenarios.