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In this work, a Mg-based energetic composites, commonly known as pyrotechnic tracer composition (Mg-PC), was successfully fabricated by a mechanical milling method. The influence of the impact of artificial heat- or moist-aging on the combustion heat, ignition characteristics, and the thermal decomposition behavior of the as-prepared composite were investigated. Results show that the total energy output has decreased by 16% and 51% for the heat- and moist-aged samples, respectively. Microcalorimetric studies revealed shorter induction times and higher heat flow magnitudes for the different aged samples. Compared with the unaged composition, the ignition time of heat- and moist-aged samples are distinctly increased by 2.2 and 14.3 times, respectively. The thermogravimetric analysis demonstrated that humidity and thermal agings have a catalytic effect and accelerate the decomposition reaction, reducing the onset temperature decomposition by about 4–6°C after aging. The kinetic deconvolution analysis (KDA) indicated a multistep reaction comprising the resin decomposition, partial decomposition of the oxidizer, and the combustion of the Mg-PC. The activation energy of the first two decomposition steps was lower than that of the as-prepared mixture. Furthermore, the combustion process, corresponding to the third step exhibited slightly higher activation energy compared to the unaged formulation and is assigned to the fuel oxidation and the pre-decomposition of the oxidizer under heat- or moist-aging. [ABSTRACT FROM AUTHOR]

This study explored the stability and thermo‐kinetic features of double base nitrocellulose (NC)/diethylene glycol dinitrate (DEGDN) propellant supplemented with Kraft lignin. For this purpose, the impact of 2‐nitrodiphenylamine (2‐NDPA), 1,3‐dimethyl‐1,3‐diphenylurea (C‐II) and lignin stabilizers on the molecular structure, morphology, and thermokinetic behavior of NC/DEGDN composite were thoroughly analyzed. Experimental results showed that lignin exhibits promising stabilizing efficiency comparable to that of the conventional 2‐NDPA and C‐II. In addition, thermal findings highlighted that the incorporation of 2‐NDPA, C‐II, and lignin has improved the thermal decomposition temperature of NC/DEGDN propellant. The investigation of the thermolysis kinetics of stabilized NC/DEGDN composites demonstrated an increase in the Arrhenius parameters with respect to the NC/DEGDN baseline. Above all, this investigation contributes to the ongoing efforts to develop new environmentally friendly stabilizers for nitrate esters‐based composites. [ABSTRACT FROM AUTHOR]

Nitrogen oxides (NOx), which result from the decomposition of nitrocellulose (NC)-based solid propellants, promote the degradation of this later and alter its long-term stability. Thus, to avoid such situation and ensure a better stability, conventional stabilizers such as aromatic amines or urea compounds are usually added to the NC-based formulations. However, these latter may generate carcinogenic and toxic species that may negatively affect both human health and environment. Herein, based on its selective adsorption capacity of NOx, the stability potential of a porous inorganic compound, namely, mordenite (MOR), on nitrocellulose was assessed. Three NC-based samples (S1–S3) were prepared through the incorporation of 3 wt.% of stabilizing agents, i.e., S1: pure NC, S2: NC + DPA, and S3: NC + MOR. The effect on the stability of this inorganic compound with regard to pure NC has been highlighted utilizing stability tests and kinetic modeling. Beforehand, the compatibility of mordenite with nitrocellulose was initially checked by means of DSC and FTIR. Furthermore, the obtained results via Vacuum Stability Test (VST) and Bergmann–Junk (B&J) test demonstrated that S3 displayed a better stability than S1 and comparable behavior to S2. The determination of the kinetic triplet by isoconversional methods confirmed the effectiveness of MOR as a stabilizing agent. These findings claim that such inorganic compound may be used efficiently as a stabilizer for NC-based energetic formulations. [ABSTRACT FROM AUTHOR]

In the present work, a green synthesis of copper oxide nanoparticles (CuO NPs) has been performed through a precipitation method using three different copper precursors and sylvestrys leaf extract as a capping agent. Morphology and structure of the obtained CuO NPs were confirmed by X‐ray diffraction (XRD), ultraviolet‐visible (UV/Vis), Fourier transform infrared (FT‐IR) and Raman spectroscopy, as well as scanning electron microscopy (SEM). Moreover, their thermal behavior and catalytic performance were studied using thermogravimetry (TG) and differential scanning calorimetry (DSC). Four isoconversional kinetic methods have been applied to the DSC data obtained at different heating rates in order to determine the kinetic triplets. The results showed that the introduction of CuO NPs has noticeably lowered the thermal decomposition temperature by 91.7, 89.9, and 83.0 °C, and increased the exothermic enthalpy by 1053, 832, and 962 J·g–1 for AP‐CuO‐S, AP‐CuO‐N, and AP‐CuO‐Cl, respectively. Furthermore, CuO NPs were found to reduce the activation energy of AP decomposition. Besides that, ammonium perchlorate decomposes following different reaction models g(α), depending on the decomposition stage and the addition of CuO NPs. These results indicate further that the green synthesized CuO nanoparticles are promising ballistic modifiers for composite solid propellants. [ABSTRACT FROM AUTHOR]

Organic eutectics, as well as aniline-based compounds, were recently found to be efficient stabilizers for solid propellants. In the current work, compatibility of nitrocellulose (NC) with the conventional stabilizer (Diphenylamine (DPA)), one aniline-based compound (N-(2-ethanol)-p-nitroaniline (ENA)), and their eutectic composition (Diphenylamine + N-(2-ethanol)-p-nitroaniline) have been investigated by thermal techniques according to well-known standards. The compatibility and thermal stability of NC mixtures were further explored using stability tests, kinetic modeling via different isoconversional methods, and the determination of the isokinetic temperature. DPA was found to be highly compatible with NC, whereas compatibility issues appeared once ENA, as well as the eutectic (DPA+ENA), are present in the NC mixture. Moreover, the obtained results suggest an incompatibility between the stabilizers (ENA and DPA) in the eutectic mixture. Finally, it was found that the thermal stability of the NC-based energetic materials was adversely affected if a compatibility problem is observed between the stabilizers and nitrocellulose. [ABSTRACT FROM AUTHOR]

In this study, microcrystalline cellulose nitrate (MCCN) as energetic polymer is successfully obtained from Posidonia oceanica brown algae (POBA). Fourier transform infrared spectroscopy (FTIR) results show alterations in the intensities of some absorption bands, suggesting a significant difference in the chemical structure between microcrystalline cellulose and the emergent MCCN samples. X‐ray diffraction (XRD) measurements indicate that MCCNs are more crystalline than conventional nitrocellulose (NC). According to scanning electron microscopy (SEM), both NC and MCCN reveal a compact structure and a rough surface. Differential scanning calorimetry (DSC) displays that the thermal degradation of MCCNs shifts to lower temperatures compared to the respective NCs. Furthermore, in comparison with NC samples, MCCN samples exhibit high density, high nitrogen content, low viscosity‐average molecular weight, and good thermal stability. On the other hand, kinetic modeling based on DSC data is carried out by isoconversional integral methods to determine Arrhenius parameters and the decomposition mechanisms. It is found that MCCNs present lower activation energies than conventional NCs with a decrease of ≈6%. Finally, this work opens a new pathway to prepare MCCN from POBA, and it is expected to have applications in several areas such as propellants, energetic binders, and gas generators. [ABSTRACT FROM AUTHOR]