The positive correlation between the dispersion and catalytic performance of Fe2O3 nanoparticles in nano-Fe2O3-ultrafine AP energetic composites supported by solid UV-vis spectroscopy

Recently, the widespread use of nanocatalytic materials has contributed to an enormous improvement in the performance of energetic materials, especially, highly dispersed nanomaterials. However, the lack of quantitative methods for analyzing the dispersion of nanomaterials limits their further widespread use. Although various techniques such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), etc. are used to analyze the relative dispersion of nanomaterials, it is not possible to quantitatively analyze their dispersion. Therefore, there has been an effort to develop new methods for the quantitative analysis of nanocatalytic materials. Fortunately, we were able to analyze the dispersion of nanocatalytic materials using the difference in their UV absorbance. More importantly, we established the corresponding difference equation to quantify the dispersion of nanocatalytic materials, which is capable of quantifying the dispersion of nano-Fe2O3 in nano-Fe2O3-ultrafine AP composites. The accuracy of the difference equation was verified using a variety of techniques and the desired results were obtained. Based on the above conclusions, the quantitative analysis method for the dispersion of nanomaterials that we established is expected to be widely used and promote the development of energetic materials.

Construction of Hydrophobic Ammonium Perchlorate with Synergistic Catalytic Effect Based on Supramolecular Self-Assembly for Synchronously Catalyzing the Thermal Decomposition of Ammonium Perchlorate and the Combustion of Aluminum

Ammonium perchlorate (AP), as an important additive component of composite propellants, is critical to the combustion performance of propellants. Herein, AP@1H,1H,2H,2H-perfluorodecyltrichlorosilane (AP@PF) was prepared by establishing a tannic acid-iron ion (TA-Fe) supramolecular self-assembly layer on the AP surface and connecting the 1H,1H,2H,2H-perfluorodecyltrichlorosilane interfacial layer. Results demonstrate that TA-Fe and 1H,1H,2H,2H-perfluorodecyltrichlorosilane are uniformly bound to the surface layer of AP. AP@PF has a lower high-temperature thermal decomposition peak compared to AP. Meanwhile, the exothermic values of low-temperature thermal decomposition (338 J/g) and high-temperature thermal decomposition (597 J/g) of AP@PF are significantly higher than those of AP. In addition, AP@PF exhibits different surface interfacial properties, such as floating on the water surface and exhibiting a static contact angle of 105° on water. AP@PF shows almost no moisture absorption after aging in humid air for 30 days. The exothermic value of the mixture of AP@PF and aluminum powder (156 J/g) is significantly higher than that of the mixture of AP and aluminum (54 J/g), and the mixture of AP@PF and aluminum powder exhibits a higher calorific value and a stronger emission spectrum. Finally, the synergistic catalytic mechanism of AP@PF on the thermal decomposition of AP and the combustion of aluminum powder is also discussed.

Preparation of a Chitosan-Lead Composite Carbon Aerogel and Its Catalytic Thermal Decomposition Performance on Ammonium Perchlorate

Chitosan-lead (CS-Pb) carbon aerogels were prepared by ionic cross-linking and high-temperature carbonization using chitosan (CS) as the carbon precursor. The obtained carbon aerogels were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffractometry (XRD), and X-ray photoelectron spectroscopy (XPS). The obtained aerogels have a 3D structure and a large surface area, which can effectively prevent the agglomeration phenomenon of metals. Differential thermal analysis (DTA) was used to analyze the catalytic performance of a carbon aerogel for ammonium perchlorate (AP). The results showed that the CS-Pb carbon aerogel reduced the peak temperature of AP pyrolysis from 703.9 to 627.7 K. According to the Kissinger method calculations, the E_a of AP decomposition decreased about 27.2 kJ/mol. The TG data at different warming rates were analyzed by the Flynne-Walle-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) methods, which are two of the isoconversion methods, and the activation energies of AP and AP+CS-Pb-3.5 were calculated. Between the conversion degrees (α) of 0.1 and 0.9, the E_a values obtained by the two isoconversion methods are similar and have a certain match. Also, the two isoconversion methods confirm Kissinger's calculation. Finally, thermogravimetry-mass spectrometry (TG-MS) was used to monitor the gases generated during the thermal decomposition of the AP+CS-Pb-3.5 system in real time.

Energetic bimetallic complexes as catalysts affect the thermal decomposition of ammonium perchlorate

Two bimetallic complexes of 4-hydroxy-3,5-dinitropyrazole, [K₂Mn(DNPO)₂(H₂O)₄]_n·2H₂O (BMEP-1) and [K₂Zn(DNPO)₂(H₂O)₆]_n (BMEP-2), were synthesized and characterized by IR spectroscopy and elemental analysis. The crystal structures of BMEP-1 and BMEP-2 were determined by single-crystal X-ray diffraction. It is noteworthy that these complexes presented different metal-organic frameworks. The thermal behaviors of BMEP-1 and BMEP-2 were investigated by differential scanning calorimetry and thermogravimetric analysis measurements. These bimetallic complexes exhibited high thermal stability (348.0 °C and 331.0 °C) due to their large coordination bonds and three-dimensional interconnected structure. The catalytic performances of BMEP-1 and BMEP-2 on the thermal decomposition of ammonium perchlorate were investigated by TGA-DSC, TGA-FTIR, and non-isothermal kinetic analyses. The results showed that BMEP-1 and BMEP-2 exhibited excellent catalytic performance in the thermal decomposition of ammonium perchlorate. Notably, there was only a single exothermic peak at 302.6 °C and 318.6 °C, and the activation energy values of ammonium perchlorate decreased to 123.88 kJ mol^-1 and 128.43 kJ mol^-1, respectively. TGA-FTIR results showed that BMEP-1 and BMEP-2, as effective components of catalysis, will promote the production of H₂O, N₂O, NO₂, and HCl in advance, during the thermal decomposition of ammonium perchlorate. BMEP-1 and BMEP-2 are expected to be two candidate additives for the catalytic decomposition of ammonium perchlorate in composite solid propellants.

Study on the thermal decomposition behavior of ammonium perchlorate catalyzed by Zn–Co cooperation in MOF

The combustion performance of solid propellants plays a decisive role in the overall application of rockets.

Optimized energetic HNTO/AN co-crystal and its thermal decomposition kinetics in the presence of energetic coordination nanomaterials based on functionalized graphene oxide and cobalt

The present research aims to select the optimal molar ratio of hydrazine 3-nitro-1,2,4-triazol-5-one (HNTO) and ammonium nitrate (AN) to produce an energetic co-crystal. For a comparison purpose, the heat release, cost, density and hygroscopicity of the different co-crystals were evaluated. The obtained results indicated that HNTO/AN at the 1 : 3 ratio exhibited a higher heat release, better thermal stability, low water content and a reasonable cost, compared to other co-crystals. This new co-crystal was fully characterized through powder X-ray diffraction (XRD), infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC), confirming that this latter displayed similar characteristics to those of the co-crystal with a 1 : 1 ratio, which was recently developed. On the other hand, the catalytic activity of two energetic coordination polymers of triaminoguanidine-cobalt (T-Co) complexes, with or without graphene oxide (GO-T-Co-T), on the thermolysis of the developed co-crystal has been also assessed by DSC under non-isothermal conditions. It is revealed that these catalysts have greatly decreased the decomposition temperature of the HNTO/AN cocrystal. Moreover, because of the complete decomposition in the case of the (HNTO/AN)/GO-T-Co-T composite, the heat release has been increased as well. Isoconversional integral kinetic methods were exploited to determine the kinetic parameters of the different systems. According to the obtained results, these catalysts have a strong catalytic action on the decomposition of the co-crystal AN/HNTO for which the activation energy and the pre-exponential factor are considerably lowered. Consequently, the developed co-crystal and the energetic catalysts could be considered as potential ingredients for the next generation of composite solid propellant formulations.