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Ionic liquids (ILs) are the safest solvent in various high-temperature applications due to their non-flammable properties. In order to obtain their thermal stability properties, thermogravimetric analysis (TGA) is extensively used to analyze the kinetics of the thermal decomposition process. This review summarizes the different kinetics analysis methods and finds the isoconversional methods are superior to the Arrhenius methods in calculating the activation energy, and two tools—the compensation effect and master plots—are suggested for the calculation of the pre-exponential factor. With both parameters, the maximum operating temperature (MOT) can be calculated to predict the thermal stability in long-term runnings. The collection of thermal stability data of ILs with divergent cations and anions shows the structure of cations such as alkyl side chains, functional groups, and alkyl substituents will affect the thermal stability, but their influence is less than that of anions. To develop ILs with superior thermal stability, dicationic ILs (DILs) are recommended, and typically, [C4(MIM)2][NTf2]2 has a decomposition temperature as high as 468.1 °C. For the convenience of application, thermal stability on the decomposition temperature and thermal decomposition activation energy of 130 ILs are summarized at the end of this manuscript.

A thermal-oxidative aging test at 120 °C was conducted on ethylene propylene diene monomer (EPDM) vulcanizates of the semi-efficient vulcanization system. The effect of thermal-oxidative aging on EPDM vulcanizates was systematically studied by curing kinetics, aging coefficient, crosslinking density, macroscopic physical properties, contact angle, Fourier Transform Infrared Spectrometer (FTIR), Thermogravimetric analysis (TGA) and thermal decomposition kinetics. The results show that the content of hydroxyl and carbonyl groups as well as the carbonyl index increased with increasing aging time, indicating that EPDM vulcanizates were gradually oxidized and degraded. As a result, the EPDM vulcanized rubber chains were crosslinked with limited conformational transformation and weakened flexibility. The thermogravimetric analysis demonstrates that the thermal degradation of EPDM vulcanizates had competitive reactions of crosslinking and degradation, and the thermal decomposition curve can be divided into three stages; meanwhile, the thermal stability of EPDM vulcanizates gradually decreased with increasing aging time. The introduction of antioxidants in the system can promote the crosslinking speed and reduce the crosslinking density of EPDM vulcanizates while inhibiting the surface thermal and oxygen aging reaction. This was attributed to the fact that the antioxidant can reduce the thermal degradation reaction level, but it is not conducive to the formation of a perfect crosslinking network structure and reduces the activation energy of thermal degradation of the main chain.

The accompanying health and environmental issues have prompted a renewed effort to find more environmentally friendly substitutes for ammonium perchlorate (AP) as a solid rocket propellant oxidizer. AP Propulsion’s outstanding performance is complemented by environmental concerns, which search for greener options necessary. Ammonium nitrate (AN) has emerged as a viable alternative that provides cost-effectiveness, non-detectable and tractable properties to the adversary, and cleaner combustion products. Structural instability is one of the problems with AN-based propellants. This work aims to overcome this obstacle by creating green energetic molecular perovskite based on nitrate groups (NO 3 − ). NH 4 (C 6 H 12 N 2 )(NO 3 ) 3 (DAN-4) was synthesized by molecular assembly technique. Scanning electron microscope (SEM), X-ray diffraction (XRD), and Fourier transfer infrared (FTIR) were applied to characterize the structure and morphology of AP, AN, and DAN-4. Thermal decomposition of AP, AN, and DAN-4 were investigated using differential scanning calorimetry (DSC), and thermal gravimetric analysis (TGA). The results show that DAN-4 has one exothermic peak at 201 °C with 1420 J/g heat evolved compared to AN which has two endothermic phase transitions at 54 °C, and 128 °C respectively, melting point at 170 °C, and thermal decomposition at 294 °C with no exothermic peak, and heat evolved. DAN-4 shows higher energy released than common oxidizer (AP) which evolved 836 J/g. Decomposition kinetics was investigated via isoconversional (model free) and model fitting. Kissinger, Kissinger–Akahira–Sunose (KAS), integral isoconversional method of Flynn–Wall–Ozawa (FWO). DAN-4 demonstrated an apparent activation energy of 211.1 ± 1.66 kJ/mol compared with 160.8 ± 1.07 kJ/mol for pure AP, and 143.82 ± 3.3 kJ/mol for pure AN. DAN-4 shows higher thermal stability than AP, and AN. This work could promote the application of DAN-4 in the field of composite solid rocket propellant.

This paper presents experimental research on the flame-retardant properties and thermal decomposition kinetics of wood treated by boric-acid-modified silica sol. The poplar wood was impregnated with pure silica sol and boric-acid-modified silica sol. The results showed that modifiers can be observed in the cell wall and cell lumen. The ignition time, second peak of the heat release rate, total heat release, and mass loss of the W-Si/B were delayed obviously. The composite silicon modification had a positive impact on carbonization. Thermogravimetric analysis showed that the residual mass of W-Si/B was enhanced and the thermal degradation rate was considerably decreased. By thermal decomposition kinetics analysis, the boric acid can catalyze the thermal degradation and carbonization of poplar wood. In other words, wood treated with boric-acid-modified silica sol showed significant improvement in terms of flame retardancy, compared with wood treated with common silica sol.

Thailand has plentiful rubberwood biomass for biofuel and bioenergy applications, as well as for carbon material production. One of the keys to choosing a biomass conversion process is its effects on the physicochemical properties. In addition, thermochemical conversion of biomass also requires knowledge of its thermal decomposition behavior and kinetics for reactor design; and specification of operating conditions. Thus, the aims of this research were to explore the physicochemical properties of rubberwood biomasses (RWBs) generated alternatively from branches, trunks, and roots. The rubberwood biomass with the best energy properties was then selected to investigate its thermal decomposition behavior and kinetics. The physicochemical properties of RWBs determined were the gross and elemental components, energy properties, lignocellulosic components, and major noncombustible elements. Thermal decomposition observations were carried out by using the thermogravimetric analyzer under a nitrogen atmosphere at heating rates of 5, 10, 20, and 30 °C min −1 . The kinetic analysis was conducted by applying the iso-conversional model-free methods of Friedman, Kissinger–Akahira–Sunose (KAS), and Ozawa–Flynn–Wall (OFW). Based on statistical analysis, the results highlighted that the trunks (RTT) possessed the best energy properties. The lignocellulosic and elemental components of RWBs had small differences. The activation energy derived from iso-conversional methods demonstrated consistency with previous studies. The activation energies were in the ranges 159.11–210.61, 168.89–175.06, and 169.96–176.01 kJ mol − 1 according to the Friedman, KAS, and OFW methods, respectively. These explorations are useful for applying the RWB as feedstock in torrefaction and pyrolysis applications.

This investigation delves into the thermal decomposition kinetics and thermal hazards of the water-soluble azo initiator, 2,2′-azobis[2-(2-imidazolin-2-yl) propane] dihydrochloride (AIBI), starting with an examination of phase changes and reactions during AIBI heating. Initially, a thermogravimetric analyser was employed to assess the sample, applying a heat-wait-heat approach to observe exothermic reactions upon heating to the decomposition point. This process revealed reactions initiating around 160 °C, a critical temperature for phase transition identified in previous research. However, no noticeable phase change was observed, consistent with earlier reports noting mass loss at this temperature, highlighting the nuanced phase behaviour of AIBI. Further analysis utilised differential scanning calorimetry alongside the isoconversional kinetic analysis via the Flynn–Wall–Ozawa method to investigate AIBI’s thermal decomposition. This comprehensive approach revealed a complex decomposition process with an apparent activation energy of approximately 150 kJ mol –1 , underscoring the need for careful temperature management during storage and transport to forestall autocatalysis, recommending an ambient temperature below 100 °C and incorporating a model-free methodology as a preliminary step allowed for an initial assessment of the reaction’s kinetics, providing a broader understanding of the decomposition behaviour. Following this, a model-based approach was employed for advanced verification, such as determining the specific reaction model, f ( α ) and conducting further kinetic calculations. This two-pronged analysis strategy enriched our insight into AIBI’s thermal hazard behaviour, enabling a more accurate prediction of thermal hazards and informing safer handling and storage practices. The study confirms the intricate thermal decomposition characteristics of AIBI. It highlights employing both model-free and model-based methodologies for a comprehensive understanding of thermokinetics and safety profiles.

In this study, four types of waste bamboo fibers (BFs), Makino bamboo (Phyllostachys makinoi), Moso bamboo (Phyllostachys pubescens), Ma bamboo (Dendrocalamus latiflorus), and Thorny bamboo (Bambusa stenostachya), were used as reinforcements and incorporated into polypropylene (PP) to manufacture bamboo–PP composites (BPCs). To investigate the effects of the fibers from these bamboo species on the properties of the BPCs, their chemical compositions were evaluated, and their thermal decomposition kinetics were analyzed by the Flynn–Wall–Ozawa (FWO) method and the Criado method. Thermogravimetric results indicated that the Makino BF was the most thermally stable since it showed the highest activation energy at various conversion rates that were calculated by the FWO method. Furthermore, using the Criado method, the thermal decomposition mechanisms of the BFs were revealed by diffusion when the conversion rates (α) were below 0.5. When the α values were above 0.5, their decomposition mechanisms trended to the random nucleation mechanism. Additionally, the results showed that the BPC with Thorny BFs exhibited the highest moisture content and water absorption rate due to this BF having high hemicellulose content, while the BPC with Makino BFs had high crystallinity and high lignin content, which gave the resulting BPC better tensile properties.

Numerous theoretical calculations have demonstrated that polynitrogen with an extending polymeric network is an ultrahigh-energy all-nitrogen material. Typical samples, such as cubic gauche polynitrogen (cg-N), have been synthesized, but the thermal performance of polynitrogen has not been unambiguously determined. Herein, macroscopic samples of polynitrogen were synthesized utilizing a coated substrate, and their thermal decomposition behavior was investigated. Polynitrogen with carbon nanotubes was produced using a plasma-enhanced chemical vapor deposition method and characterized using infrared, Raman, X-ray diffraction X-ray photoelectron spectroscopy and transmission electron microscope. The results showed that the structure of the deposited polynitrogen was consistent with that of cg-N and the amount of deposition product obtained with coated substrates increased significantly. Differential scanning calorimetry (DSC) at various heating rates and TG-DSC-FTIR-MS analyses were performed. The thermal decomposition temperature of cg-N was determined to be 429 °C. The apparent activation energy (Ea) of cg-N calculated by the Kissinger and Ozawa equations was 84.7 kJ/mol and 91.9 kJ/mol, respectively, with a pre-exponential constant (lnAk) of 12.8 min−1. In this study, cg-N was demonstrated to be an all-nitrogen material with good thermal stability and application potential to high-energy-density materials.

HMX/RDX composites were prepared using the solvent-antisolvent alternating method. The morphology and structure of the composites were characterized by optical microscopy, high-performance liquid chromatography (HPLC), Fourier transform infrared spectroscopy (FT-IR), and powder X-ray diffraction (PXRD). The composite exhibited a morphology with HMX as the core and RDX as the coating layer. The HMX existed in the β-phase, and molecular interactions were observed between the two components (a blue shift of 2.06 cm − 1 in the NO 2 symmetric stretching vibration peak of HMX and a red shift of 2.06 cm − 1 in the C-H stretching vibration peak of RDX). Thermal analysis revealed synergistic effects in the thermal decomposition process (lower decomposition peak temperature for HMX and higher for RDX), with an apparent activation energy (149.41 kJ/mol) in the first decomposition stage lower than that of the physical mixture and pure RDX component. Concurrently, both the critical thermal detonation temperature (227.74 ℃) and self-accelerating decomposition temperature (213.78 ℃) exceed those of the physical mixture and pure RDX component, thereby demonstrating superior thermal safety. This composite material strikes a balance between energy release efficiency and safety, offering significant application value for weapon systems that pursue higher performance and lower vulnerability. It also provides a novel approach and technical pathway for high-energy explosive formulation design.

The ultrafine MoO3 powders were prepared by the combination of centrifugal spray drying and calcination in this work. The thermal decomposition behavior of the spherical precursor was studied. The phase constituents, morphologies, particle size, and specific surface areas of MoO3 powders were characterized at different temperatures. It is found that the decomposition of the precursor is subjected to five stages, and forms different intermediate products, including (NH4)8Mo10O34, (NH4)2Mo3O10, (NH4)2Mo4O13, h-MoO3, and the final product α-MoO3. Moreover, the decomposition rate equation is established based on the thermal decomposition kinetic parameters of the precursor. With an increase in decomposition temperature, the morphology changes from unclear boundary particles to dispersed flake particles, and the flaky particles exhibit larger sizes, higher crystallinity, and better dispersion, which can be attributed to the mass transfer of gaseous MoO3 products. Additionally, the MoO3 particle size decreases progressively, and the specific surface area increases and then decreases. At 500 °C, it can achieve ultrafine flaky MoO3 powder with the size of thick sheets, with a thickness of about 300 nm and a length of about 1–3 μm. This research can offer an innovative strategy for preparing ultrafine MoO3 powder.