Conventional ferrocene derivatives exhibit limited efficacy in regulating the combustion of composite propellants, and the underlying combustion mechanism remains unclear. It becomes imperative to explore the modification of conventional ferrocene derivatives and their application in composite propellants, with the aim of unraveling the intricate combustion mechanism involved. In this study, we synthesized three novel highnitrogen energetic ferrocene derivatives, namely MAFcNO3, MAFcPA, and MAFcNTO, and investigated their potential as catalysts for hydroxyl-terminated polybutadiene solid propellants, and subjected to explore their thermal decomposition and combustion characteristics. The burning rates of the propellants showed significant improvements. Notably, the propellants containing MAFcPA exhibited the lowest pressure exponent of 0.39 within the pressure range of 1-10 MPa. The addition of MAFcPA to the HTPB propellant led to an increase in the combustion flame temperature from 2229.41 degrees C to 2349.91 degrees C. Auto-ignition experiments conducted using a rapid compression machine, the results demonstrated a significant enhancement in the combustion energy release rate of the propellant. Thermal decomposition experiments revealed that MAFcPA facilitated the decomposition of ammonium perchlorate (AP) and hydroxyl-terminated polybutadiene (HTPB), as well as the melting of aluminum (Al). Combustion experiments further elucidated that the decomposition of MAFcPA yielded ferric oxide. The gaseous products of the propellant combustion included CH4, H2O, CO, CO2, H2C--CH2, CH---CH, HCN and O2, while the combustion residues consisted of Al, Al2O3, Al4C3, Al2OC and Fe2O3. This work demonstrates the efficient combustion catalytic effect of three high-nitrogen energetic ferrocene derivatives for solid propellants binded with hydroxyl-terminated polybutadiene.

The evolution of damage features such as pores and cracks during long-term storage is a critical factor affecting the ignition and combustion performance of high-energy propellants. In this work, the influence of thermally induced pore damage on the ignition and combustion performance is investigated experimentally. The pore damage in the high-energy propellant induced by thermal aging at 80 degrees C exhibits a distinct three-stage evolution. This progression closely correlates with the trends in ignition delay time and burning rate. Based on the observed synergistic evolution and interaction between mesoscopic damage and combustion flames in the combustion interface of severely aged propellants, the novel concept of "damage-coupled combustion" is proposed for the first time to characterize this behavior. Various types of mesoscopic damage are observed in these aged propellants, mainly including heterogeneous interfacial cracking, transgranular fracture of particles, intraparticle pores and binder matrix fibrillation. Furthermore, an empirical model correlating aging time, pore damage and combustion performance is established through statistical regression and dimensional analysis, with a goodnessof-fit of 0.98 achieved. Consequently, a strong correlation exists between mesoscopic damage and combustion performance, which is crucial for accurately assessing the safety and reliability of high-energy composite propellants.

Low combustion efficiency is a challenge of aluminum (Al) particles in solid propellants, especially in small solid rocket motors. Therefore, it is necessary to adjust the combustion performance of Al to improve the energy release of solid propellants. Here, a core–shell structured Al-based composite Al@IL/FG with high combustion efficiency has been prepared through ionic liquid (IL) and fluorinated graphene (FG) coating. It is seen that IL can form a smooth coating layer on the surface of Al particles and encapsulate fluorinated graphene inside the coating layer. Thermal analysis results show that the coating layer can lower the reaction temperature of Al in the solid propellants due to the surface activation reaction between the Al and IL/FG. After substituting Al@IL/FG with Al, the residual Al content in the condensed combustion products of solid propellants decreased by 11.37%. In addition, compared with Al-based propellant, the d (0.5) of condensed combustion products of Al@IL/FG-based solid propellant was reduced from 69.157 to 21.559 μm. These results indicate that Al@IL/FG has a higher combustion efficiency than Al in solid propellants.

Transition metal oxides exhibit inherent catalytic activity for ammonium perchlorate (AP) decomposition; however, their performance is limited by the scarcity of accessible active sites and low conductivity. Therefore, morphology-directed structural design and interfacial engineering are highly desirable. In this study, twodimensional (2D) MCo2O4 nanosheets (M = Fe, Ni, Cu, and Cr) were synthesized via a thermal expansion method and subsequently combined with three types of carbon materials Cx (Cx = rGO, CNTs, and g-C3N4) to construct 2D MCo2O4/Cxcomposites. Structural analyses demonstrate that the intimate interfacial coupling between 2D MCo2O4 nanosheets and carbon materials effectively suppresses restacking and establishes a continuous conductive network. More importantly, strong interfacial coupling enables effective electronic modulation at the heterojunction, resulting in an optimized charge distribution and enhanced interfacial electron transfer. Among all catalysts, 5 wt. % FeCo2O4/rGO-1 demonstrates the most notable catalytic activity for AP decomposition, reducing its peak temperature in the high-temperature decomposition stage by 137.4 degrees C and increasing its heat release by 736.33 J & sdot;g-1. Electrochemical tests confirm that accelerated interfacial charge transfer enhances AP pyrolysis. Kinetic modelling, TG-FTIR-MS, and DFT calculations indicate that the 2D-2D heterointerface boosts the adsorption of the AP intermediate NH3 and promotes its conversion into higher-valence NO2, while also accelerating electron transport and lowering the decomposition barrier. The synergistic effect between interfacial electron transport and the heterojunction promotes the rapid AP degradation. Based on these findings, a plausible catalytic mechanism for AP decomposition is proposed.

Hydrazine salt of 5-aminotetrazole (HAT) is an excellent material for use in gas generator solid propellants due to its extremely high amount of nitrogen. Combustion performance is an important indicator of solid propellant. The investigation of thermal behaviors could offer insights into enhancing combustion performance through the strategic addition of catalysts. However, discovering highly effective catalysts is challenging. So, for this purpose, we investigated the catalytic activity of catalysts at three different categories and scales (metal oxide microFe2O3, nano-Fe2O3, and liquid metal-organic compound ferrocene-based derivative catocene) on the thermal decomposition behaviors of HAT. The thermal decomposition process of HAT is performed at temperatures ranging from 50 to 550 degrees C employing a combined DSC-TG-FTIR-MS technique. The most probable thermal decomposition route of HAT was inferred by capturing the released gas products. The thermal activation energy is evaluated using Friedman isoconversional method. The results reveal that the activation energy is the highest in stage II of the thermal decomposition process, indicating that the catalytic effect of the catalyst is primarily manifested in stage II. The Criado with model-fitting method is used to identify the possible thermal decomposition reaction models. The findings indicate that the thermolysis model is not guided in any particular model, rather it is consistent with the Fn model. The catalytic activity of the catalysts was also analyzed based on frontier molecular orbitals theory. The findings indicate that the incorporation of the liquid metal-organic compound catocene is an effective way to accelerate its thermal decomposition rate. This suggests that the particle size dominates the catalytic effect, but the molecular orbitals also have some influence on the catalytic performance. The conclusion of this study is beneficial for optimizing, managing, and applying the combustion performance of HAT-based solid propellants.

To improve the interfacial performance between hydroxyl-terminated polybutadiene (HTPB)-based polyurethanes and polar propellants, this study addresses the intrinsic polarity mismatch between the two components and proposes a facile chemical modification strategy based on the step-growth copolymerization method, in which polar polyether segments are incorporated into the HTPB backbone. This approach features low cost, simple processing, and promising scalability for practical applications. Poly(propylene oxide) diol (N210), polytetrahydrofuran (PTMEG), and polyethylene glycol (PEG) were employed as representative polyethers to modify HTPB, and a series of polyether-modified HTPB-based polyurethane films and bonded assemblies were prepared accordingly. The effects of polyether type and content on the microphase structure, mechanical properties, surface polarity, and interfacial adhesion strength of the materials were systematically investigated using Fourier-transform infrared spectroscopy, scanning electron microscopy, mechanical testing, contact angle measurements, and debonding tests of bonded specimens. The results demonstrate that N210 significantly enhances the elongation at break of the material (up to 623%) while markedly increasing surface polarity, as evidenced by a decrease in the water contact angle from 113.8° to 80.1°. The N210-modified liner exhibits outstanding interfacial adhesion potential, with the failure mode dominated by cohesive fracture within the propellant. In contrast, PTMEG-modified HTPB polyurethane enables a balanced combination of mechanical properties over a relatively wide composition range (10–30 wt%), while improving interfacial adhesion through optimization of the interfacial structure. The N210- and PTMEG-modified systems enhance interfacial bonding via two distinct mechanisms, namely “polarity–toughness enhancement” and “mechanical balance preservation–interface optimization,” respectively. These results highlight the effectiveness of polyether copolymerization in tailoring the interfacial performance of HTPB-based polyurethanes with polar propellants and provide valuable guidance for the rational design and selection of liner materials.

Rare earth compounds and their derived composite materials are rarely used as combustion catalysts in ammonium perchlorate (AP) thermal decomposition. The composite material Tb-Co-CM, fabricated by calcination of 10 mol.% cobalt-doped terbium Prussian blue analog at the optimal conditions, was employed as a promoter for AP pyrolysis utilizing the adjustable frameworks of PBA compounds. The as-prepared composite TbCo-CM was examined with SEM, XPS, Raman, XRD, etc., confirming its morphology and structure. The catalytic performance evaluated by the DSC technique showed that with 5 wt% Tb-Co-CM as the additive, two decomposition stages of AP were merged into one phase during its pyrolysis, advancing the AP peak temperature in the high-temperature decomposition stage by 112.6 degrees C and boosting its heat release from 679.81 J center dot g-1 to 1415.60 J center dot g-1. The electrochemical property studies revealed that Tb-Co-CM exhibited a superior electrochemical behavior, hinting that the cobalt doping in pure composite Tb-CM accelerates its electron transfer, thereby increasing the catalytic efficiency. The investigations on AP pyrolysis, probed by thermal decomposition kinetics and TG-FTIR-MS, suggested that the electron transfer plays a vital role in the key steps ClO4- to NH4+ and O2 to O2-. The increase in the electron movement enhances the relative percentages of the more stable gases. Finally, a plausible thermal degradation mechanism of AP promoted by the Tb-Co-CM composite was recommended.

Transition-metal coordination polymers are important burning rate catalysts (BRCs) in ammonium perchlorate (AP) combustion. To address coordination polymers agglomeration and enhance their catalytic activity in AP pyrolysis, the flower-shaped undissolved copper 2-nitroterephthalate (CuNBDC) coordination polymer was prepared and was sealed in the nanochannels of carbon nanotubes (O-CNTs) to afford nanocomposite (CuNBDC@O-CNTs(C1)) by an innovative post-synthetic strategy. The structures and morphology of the assynthesized materials were verified using SEM, TEM, XPS, XRD, Raman and FT-IR. Their catalytic effect on AP pyrolysis assessment showed that CuNBDC and CuNBDC@O-CNTs(C1) exhibit excellent catalytic effects on AP thermal decomposition with 5 wt% addition, shifting left its peak temperature by 112.2 degrees C and 95.1 degrees C, respectively, and enhancing the heat release of AP by 166% and 313%, respectively. The catalytic decomposition mechanism of AP with CuNBDC and CuNBDC@O-CNTs(C1) additives, explored by thermal decomposition kinetics, TG-FTIR-MS and theoretical calculations (DFT) revealed that the interaction of the in-situ formed CuO nanoparticles with carboxyl and hydroxyl groups of CNTs mediate and accelerate the electron transfer of ClO4- to NH4+ and O-2 to O-2(-) , boosting the production of more stable gases, thereby facilitating AP degradation. A reasonable catalytic mechanism for AP thermal disintegration is ultimately proposed.

The effect of the process aid “OPS” on the rheological properties of hydroxyl-terminated polybutadiene propellant was investigated by formulating different components of high-solid-content slurry, and the change in slurry viscosity with shear rate, surface morphology of solid-phase particles, and contact angle of the relevant interfaces were characterized. The results showed that the polyalkene polyamine surfactant OPS could significantly reduce the apparent viscosity and enhance the rheological properties of the slurry, to up to a 30% reduction, and the effect was achieved by adjusting the interfacial properties of the aluminum powder and the binder system. With the addition of 0.1% OPS, the contact angle of the interface between the aluminum powder and the binder was obviously reduced, from 97° to 30°, and the wetting was significantly enhanced, so it was judged that the OPS was suitable for HTPB-based composite propellants.

Pronounced migration tendency of the ferrocene-based burning rate catalysts (FcR-BRCs) often compromises the combustion performance of prolonged stored composite solid propellants. Herein, FcR@MnECPs composites were constructed by encapsulating commercial FcR-BRCs within the nanochannels of nitrogen-rich manganese energetic coordination polymers (MnECPs) to retard FcR-BRCs migration. The morphologies and structures of the FcR@MnECPs composites were characterized by SEM, TEM, XPS, XRD, Raman and BET. Migration tests displayed negligible migration of the Cat@MnECPs (Cat = catocene) composites in pseudo-propellants at 50 degrees C. The electrochemical analysis verified that the filling of catocene in the MnDAT (DAT = 3,5-diamino-1,2,4-triazole) mesoporous cavity accelerated the electron transfer of MnDAT. Catalytic tests for ammonium perchlorate (AP) pyrolysis revealed 5 wt% Cat@MnDAT advances the high-temperature decomposition peak of AP by 98.8 degrees C and increases its heat release by 1.15 times. The XRD and XPS analysis confirmed the formation of Mn2O3-Fe2O3 heterojunction in AP catalytic disintegration. The thermal decomposition kinetics, TG-FTIR-MS, and theoretical calculations elucidated that the catalytic degradation pathway of AP with Cat@MnDAT and MnDAT as catalysts: The Mn2O3-Fe2O3 heterojunction expedites the electron transfer (promoting O2- generation) and boosts the conversion of AP into higher oxidation state nitrogen oxides. Finally, a plausible catalytic combustion mechanism for AP is proposed.

The performance of aerospace vehicles directly depends on the operation of large combustion propulsion devices. Combustion instability has long been an inevitable and challenging problem in the development of large combustion propulsion devices. In this study, the dynamic characteristics of combustion instability under different injection schemes in a Helmholtz pulse combustor were investigated experimentally. The ion concentration signals at different locations in the combustor were acquired to characterize the dynamic process of unsteady combustion with different injection parameters. The flow field characteristics and reactant components distribution of the dual jet flame were simulated numerically. The results indicate that injection schemes with a large fuel injection angle phi and nozzle hole spacing are not conducive to combustion stability. A large fuel injection angle phi and nozzle-hole spacing L can prevent fuel jet convergence, thus dividing the central flame front into two parts: one is located near the nozzle outlet with fuel-rich combustion, and the other is close to the combustor wall with fuel-lean combustion. The fuel-rich state can more easily stimulate combustion instability than the fuel-lean state. Compared with the original converging jet, the newly established fuel-rich combustion region increases the occurrence of combustion instability. Nevertheless, the excessive fuel injection angle phi and nozzle-hole spacing L may result in the peak of the combustion heat release preceding the pressure oscillation, which is not conducive to combustion instability.

Many newly developed polyurethane elastomers (PUEs) often rely on organic solvents for dissolving specific components such as chain extenders, in order to achieve improved mechanical toughness, self-healing capability, etc. However, solvents complicate the synthesis and raise multiple problems relating to post-processing, greatly limiting the application of self-healing PUEs. Herein, a novel bulk polymerization routine for synthesizing polyurea elastomers is designed by specific chain extender well-dissolved in the prepolymer, as well as moisture-assisted curing without using any solvent. The synergy of aromatic disulfide dynamic chemistry and urea bondage endowed the resultant elastomers with high toughness, ultrafast (similar to 1 s) and efficient (up to 98.6 %) self-healing capability at various temperatures (similar to-23 degrees C), resistance to puncture, colorless and transparent nature approaching the standards of photovoltaic glass. The work offers a facile, adjustable and efficient routine for constructing high-performance polyurea elastomers, which have big promise not only in the field of material science, but also in the industrial production and application of polyurethanes.

Nanoconfined composites exhibit outstanding catalytic performance for the thermal decomposition of ammonium perchlorate (AP). However, it remains a formidable challenge to construct nanoconfined catalysts when the restricted species are insoluble precipitates that form rapidly at room temperature. Herein, a general precursor-based stepwise confined strategy is proposed to encapsulate M3[Fe(CN)6]2·xH2O (M-Fe-PBA) (M = Fe, Co, Ni, Cu, Zn) within N-doped hollow carbon nanospheres (NHCs), resulting in yolk-shell structured composites, M-Fe-PBA@NHCs. Catalytic tests reveal that 5 wt.% Co-Fe-PBA@NHCs show the highest catalytic activity among the M-Fe-PBA@NHCs composites, significantly lowering the high-temperature decomposition peak of AP and increasing its heat release. Electrochemical analysis confirms that fast electron transfer of Co-Fe-PBA@NHCs facilitates AP combustion. TGA-FTIR-MS measurements further elucidate an accelerated decomposition pathway. Density functional theory calculations indicate that NH3 and O2 released during AP degradation are preferentially adsorbed on the in situ formed Co3O4/CoFe2O4, promoting O2 reduction to O2 - species and facilitating the deeper oxidation of NH3 into higher-valence NO2. Crucially, this confinement strategy enables the efficient incorporation of instantly formed insoluble species into any hollow host material with accessible voids, providing a versatile platform for the development of multifunctional nanoconfined catalysts and the rational design of high-performance confined catalysts with potential applications.

2?3-Bis(hydroxymethyl?-2?3-dinitro-1?4-butanediol tetranitrate(DNTN? is energetic material? which is the densest nitrate. The unclear thermal decomposition mechanism of DNTN has seriously hindered its application in propellants. The thermal decomposition process of DNTN was investigated by a combination of reactive force field molecular dynamics(ReaxFF MD? simulation? solid-phase in situ infrared spectroscopy(in situ IR? and TG-DSC-FTIR-MS simultaneous techniques? and the gas and solid products of the thermal decomposition were analysed? the thermal decomposition mechanism was elucidated. The results showed that the decomposition of DNTN was revealed that the process occurred in three stages. During the first stage from 127 degrees C to 147 degrees C? the O-N bond in DNTN was partially broken? releasing a minor amount of NO2 gas. In the second stage? between 147 degrees C and 220 degrees C? DNTN underwent rapid decomposition? removing the nitro groups and decomposing the quaternary carbon skeleton?accompanied by the formation and cleavage of the microcyclic structure? releasing a large amount of gases such as NO2 and CO2? and at the same time emitting a large amount of heat. The third stage? taking place within the temperature range of 240-350 degrees C? involved the high temperature pyrolysis of the remaining solid product of DNTN?which resulted in a limited release of CO2 gas? and above 300 degrees C? the remaining solidphasematerial would further react to result in the production of cyano. In this paper? the thermal decomposition mechanism of DNTN was illustrated from a multistage perspective? which had important guiding significance for its application in propellants and the follow-up research on stability mechanism

The enhancement of the anti -migration performance of ferrocene-based burning rate catalysts (BRCs) and their catalytic influence on ammonium perchlorate (AP) combustion in composite solid propellants through the confinement effect is acknowledged as an effective strategy. In this investigation, FcR@ZIF-67 nanocomposites were fabricated by introducing commercial ferrocenes (FcR = Cat, NBF, TBF, and NOF) into microporous ZIF-67 nanochannels. In the catalysis performance evaluations, the Cat@ZIF-67 exhibited prominent combustion catalytic efficiency on AP thermal decomposition by advancing the AP pyrolysis temperature peak by 111.4 degrees C and increasing its release heat by 2.3 times. Moreover, the anti -migration tests demonstrated that FcR@ZIF-67 composites remain predominantly immobile during prolonged storage at 50 degrees C. The investigation results of in -situ solid FTIR, TG-FTIR-MS, and theoretical calculations for the AP thermal degeneration with Cat@ZIF-67 as a promoter, indicated that, in the oxygen -rich environment of AP, the thermal disintegration of Cat@ZIF-67 creates a Fe2O3-Co3O4 heterostructure that facilitated the generation of reactive oxygen species. This, in turn, accelerated the pyrolysis of AP and formed more thermodynamically stable gaseous products, advancing its exothermic degradation temperature and increasing its release heat. Based on these discoveries, a hypothetical catalytic mechanism for the thermal decomposition of AP is proposed.

Abstract To compare the applicability of particle gradation models commonly used in solid propellants, a variety of particle gradation models including constant-ratio gradation, maximum loading fraction gradation, and rolling gradation model, were used in the study of three-component HTPB propellants. The initial conditions were set to configure the slurries of the propellants, and the viscosity of the slurries was measured by using a rotational rheometer, and the power model was utilized to determine the rheological superiority of the slurries. The reason for the better rheological properties of the slurries is explained in conjunction with fractal theory. The results show that the Rolling gradation model is the best suited for AP single particle gradation of the three-component HTPB propellants and that its higher applicability may be related to having a higher fractal dimension number, which is positively correlated with the rheological properties. These findings help to optimize the formulation design of a three-component HTPB composite solid propellant and improve its performance.

For alleviating agglomeration of alpha-Fe2O3 nanoparticles and improving their catalytic activities as burning rate catalysts (BRCs) in solid propellants, Fe(CO)(5) as the iron source was encapsulated into the inner space and/or loaded onto the outer surface of carbon nanotubes (CNTs) via ultrasonication with visible light and temperature control strategy. The Fe(CO)(5)-CNTs composites were subsequently transformed into alpha-Fe2O3-CNTs nanocomposites by Fe(CO)(5) pyrolysis. The as-synthesized alpha-Fe2O3-CNTs composites were utterly characterized by HRTEM, SEM, BET, XPS, FTIR, Raman, and XRD. The catalytic combustion results show that the nanocomposites are highly active in boosting the thermal degradation of ammonium perchlorate (AP). alpha-Fe2O3&CNTs(S1) nanocomposite, the most excellent one, shifts left the peak temperature of the high-temperature decomposition (HTD) region of AP by 103.7 degrees C and increases its release heat by 190 %. Moreover, a carbon nanotube with a smaller outer diameter and higher iron content is conducive to enhancing AP thermal deterioration. A possible mechanism of AP decomposition with the addition of the nanocomposites was investigated by thermal decomposition dynamics, in-situ solid-state FTIR, and gas phase FTIR-MS technique. The mechanistic research implies that the produced NH3 and HClO4 gases can be absorbed on the nanocomposite surfaces to form more superoxide anions (O-2) during AP decomposition, accelerating the generation of NO from N2O and facilitating AP disintegration at a lower temperature. A tentative AP decomposition mechanism in the presence of the alpha-Fe2O3-CNTs nanocomposites is therefore proposed.

Adding burning-rate catalysts (BRCs) is highly effective for enhancing ammonium perchlorate (AP) thermal decomposition. To mitigate BRCs' agglomeration and enhance their catalytic activity for AP pyrolysis, five metal carbonyl compounds (Mo(CO)(6), Cr(CO)(6), W(CO)(6), Fe-2(CO)(9), Mn-2(CO)(10)) were refined into oxidized carbon nanotube (CNTs) cavities, respectively, by ultrasonication. The structures of the as-prepared nanocomposites were examined with TEM, SEM, XPS, Raman, etc., confirming the successful filling of the carbonyl compounds. Electrochemical studies revealed that the Mo(CO)(6)@CNTs(N1) exhibited an enhanced electron transfer rate and superior electrocatalytic performance compared to CNTs(N1). Their catalytic performance evaluated by DSC showed that 5 wt% Mo(CO)(6)@CNTs(N1) exhibits the best catalytic effect, increasing the heat release of AP by 2904.63 J & sdot;g(-1), advancing its peak temperature by 80.6 C, and decreasing its activation energy by 100.45 kJ & sdot;mol(-1). The degradation mechanism of AP catalyzed by Mo(CO)(6)@CNTs(N1) was probed through TG-FTIRMS, in-situ solid FTIR, and theoretical calculations. The investigations suggested that the promoter in AP generates carbon nanotubes-confined MoO3 nanoparticles featuring numerous Lewis and Bronsted acidic sites, which not only improves NH3 adsorption and activation but also enhances electron transfer and accelerates O-2 conversion to O-2-, thereby facilitating AP pyrolysis. Finally, a plausible catalytic mechanism for AP decomposition is postulated.

The safety of the solid propellant molding process is vital for the stable production of high-quality propellants. Failure events caused by abnormal parameters in the molding process may have catastrophic consequences. In this paper, a Bayesian network (BN) model is proposed to assess the safety of the solid propellant granule-casting molding process. Fault tree analysis (FTA) is developed to construct a causal link between process variables and process failures. Subsequently, expert experience and fuzzy set theory (FST) are used to obtain failure probabilities of the basic events (BEs). Based on the mapping rules, FTA provides BN with reliable prior knowledge and a network structure with interpretability. Finally, when new evidence is obtained, the probability is updated with the diagnostic reasoning capability of BN. The results of the sensitivity analysis and diagnostic inference were combined to identify key parameters in the granule-casting molding process, including curing temperature, vacuum degree, extrusion, calendering roll distance, length setting value, holding time, and polish time. The results of this paper can provide effective supporting information for managers to conduct process safety analysis.

For alleviating agglomeration of α-Fe2O3 nanoparticles and improving their catalytic activities as burning rate catalysts (BRCs) in solid propellants, Fe(CO)5 as the iron source was encapsulated into the inner space and/or loaded onto the outer surface of carbon nanotubes (CNTs) via ultrasonication with visible light and ultrosonic temperature control strategy. The Fe(CO)5-CNTs composites were subsequently transformed into α-Fe2O3 filled/loaded nanocomposites by Fe(CO)5 pyrolysis. The as-prepared α-Fe2O3-CNTs composites were utterly characterized by HRTEM, SEM, BET, XPS, FTIR, Raman, and XRD. The catalytic combustion results showed that the nanocomposites were highly active in promoting the thermal decomposition of ammonium perchlorate (AP). The best one, α-Fe2O3&CNTs(S1), lowered the peak temperature of the high-temperature decomposition (HTD) stage of AP by 103.7 °C and increased heat release of AP by 331%. Moreover, a carbon nanotube with a smaller outer diameter and higher iron content is conducive to enhancing AP thermal degradation. The decomposition mechanism of AP in the presence of the nanocomposites was studied by thermal decomposition kinetics, in situ solid-state FTIR, and gas phase FTIR-MS technique. The mechanistic research implied that the nanocomposites can absorb the generated NH3 and HClO4 gases on their surfaces and form more superoxide anions (O2-) during AP decomposition, accelerating the oxidation rate of N2O to NO