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Organic peroxides (OPs) have a long history in the industry. In particular, it mainly occupies a leading position in the polymer industry, so there are still emerging substances being put into the current market and applications. However, the well-known aspect of OPs in the past is reflected in their self-reactive and hazardous properties, which have continued to expand related research in the field of safety. However, even under the rich research foundation and new safety technologies, the thermal hazards caused by emerging OPs are still heard, which means that the application of new OPs still needs attention and solutions in safety area. It is necessary to update the hazard knowledge of emerging OPs and achieve the purpose of disaster reduction. Therefore, the new OP, HTP-65W was selected for this study, starting from kinetic analysis and combining the heat transfer mode of the external system to estimate and assess the overall hazard characteristics between the material and the heat exchange of the environment. The basic experiment is carried out under the technical conditions of the isothermal calorimetric test which conformed to real situation. Evaluating the thermal hazard mode of a substance can establish the determination of safety parameters, and it is essential to the actual operation process. If the substance can be controlled at a specific ambient temperature or the decomposition reaction can be prevented, the possible hazards can be eliminated. For example, HTP-65W has shorter TMRad and TCL, which shows that HTP-65W has obvious reactivity hazards. In addition, evaluating the thermal hazards of HTP-65W in different containers can be used as a safety basis for the design of HTP-65W’s cooling system and on-site operations.

Imidazoline ionic liquids (IMILs) because of its unique performance in the synthesis, liquid phase extraction environment, energy and other fields have broad application prospects, for the safety of the unknown material, study the thermal decomposition characteristics and potential hazards is very necessary. The purpose of this study was to evaluate the risk of three IMILs during production, transportation, storage, and application using thermogravimetry (TG) and accelerating rate calorimeter (ARC). The influence of different lengths of alkyl substituents on ILs stability was systematically analyzed. The apparent activation energy (Ea) and pre–exponential factor (A) of IMILs were calculated by Flynn–Wall–Ozawa (F–W–O) and Coats–Redfern (C–R) methods. Then, the mechanical function of their decomposition reaction was obtained by using the C–R method. The kinetic compensation effect is discussed. Finally, according to the experimental data under adiabatic condition by accelerating rate calorimeter (ARC), it is proved that the runaway reaction of the three IMILs is slow. This study confirms the low potential harmfulness of the above three microorganisms, gives their safe temperature range, and provides a reference for their safe use.

Melamine is one of the most extensively applied flame retardants due to its virtue of high thermostability, weak hydrophilicity, and low pollution. For the time being, its efficiency is hardly to be ideal when it acts alone. In previous explorations, melamine could be compellingly modified on the flame retardancy when it was blended with ionic liquids or the compounds comprising cyano groups. With the aim to integrate the advantages of both the groups of substances together, the cyano ionic liquid, 1-ethyl-3-methylimidazolium dicyanamide, was combined with melamine to improve the thermal stability of this widely used flame retardant in the research. The simultaneous thermogravimetric analyzer was applied to gain related parameters to determine whether the addition of the ionic liquid has the possibility to result in the increase in residue and the improvement in the thermal properties. Model-free and Coats-Redfern methods were related together to obtain the mechanism of decomposition. The experimental results demonstrate that the cyano ionic liquid possesses a promoting synergistic effect on the thermal behaviors of melamine, indicating its outstanding application prospect in practical utilization.

Owing to splendid properties, trinitrophenol-based ionic liquid consisting of ammonium–imidazolium cation, 3,5-diamino-1,2,4-triazole picrate (DATPA), has been investigated concerning the thermal stability in this study. Differential scanning calorimeter (DSC) and thermogravimetry (TG) are used to explore the thermal behavior such as melting point, decomposition temperature, and the temperature of 10% mass loss which are the target to evaluate the thermal stability of other two picrates (picrate and 4-amino-1,2,4-triazole picrate). The results show that DATPA has better thermal stability at 251–252 °C than the other two picrates, and the melt volatility has decreased as well. Moreover, thermal kinetics parameters are calculated by changing the heating rates of DSC and TG. ASTM standard E698 and Kissinger methods are utilized to calculate, and double extrapolation is accepted to explore the mechanism function in the decomposition course, which has been defined as $$f(\alpha ) = 2.105(1{-}\alpha )[\ln (1{-}\alpha )]^{0.525}$$ in this study. Finally, an accelerating rate calorimeter is employed to study the thermal hazard of DATPA under the adiabatic condition and evaluate the level of runaway reaction through the risk matrix. According to Townsend method, we achieve the thermal kinetics parameters of DATPA under adiabatic condition. The results show that the apparent activation energy (Ea) of DATPA is 273.2 kJ mol−1 higher than many other explosives. Besides, according to the theoretical calculation, we find that DATPA has good detonation properties with high stability.

2,2′-Azobis[2-(2-imidazolin-2-yl) propane] dihydrochloride (AIBI) is a class of initiators that share water-soluble features, which was widely employed in the chemical polymerization industry. The merits of AIBI are that it can conduct smooth, stable, and controllable decomposition reaction and initiate polymerization efficiently at low temperature and concentration. Unfortunately, due to the high formation enthalpy and through a large amount of gas release, AIBI has high-potential thermal hazards. Therefore, the thermal behavior of the whole decomposition process is analyzed through series of simultaneous thermogravimetric analyzer and differential scanning calorimetry tests coupled with the advanced thermal investigation. It is found that AIBI would rapidly decompose and abruptly release an enormous amount of heat in the range of 170 to 180 °C, but with only 10% mass loss in this period. These thermal parameters can be used to describe the thermal stability of AIBI, thus effectively preventing the thermal hazard and loss of control of AIBI in the process of production, transportation, and storage.

Organic peroxide (OP) has been applied in the industry for at least 40 years. Driven by significant investments in today’s high-profile energy, petrochemical, and polymer industries, the market and applications of OPs are expanding rapidly. However, the self-reactive nature has led to continuous research work on this topic. Nevertheless, tremendous progress has been made in hazard analysis, which has improved existing protocols or led to the discovery of new safety methods. OPs still cause related chemical hazards, and the limitations related to process hazards remain to be resolved. There is a lack of comprehensive systematic analysis of the process hazards of a wide variety of OPs. Different OPs, namely BPO, LPO, and the emerging OP, HTP-65W, were selected for investigation with several calorimetry techniques based on thermokinetic and heat transfer models. Determination methods have a crucial role in an operator for obtaining a systematic understanding of hazard properties under different process conditions, which is related to avoiding the occurrence of process disasters. For example, LPO has a shorter TMRad and TCL (

Free radical polymerization is an effective method for large-scale production of various olefin polymers, in which the initiator is one of the emphases in the study of different chain reaction mechanisms in chemical industry. The azo compounds are widely used in organic synthesis to initiate chain reactions. Azos are divided into different types according to the applicable temperature range. 2,2′-Azobis(2-methylpropionitrile) is suitable for moderate temperatures and well known. In the past, the chemical and free radical reactions of 2,2′-Azobis(2-methylpropionitrile) have been studied. However, the kinetic model and reaction mechanism of initiators under process conditions are still lacking. The thermal hazard characteristics evaluated by process situation of 2,2′-Azobis(2-methylpropionitrile) were discussed in this study. The kinetics analysis on AIBN is based on detailed information including rate constants, reaction orders and activation energies of the decomposition reaction. Simulated heat exchange patterns of initiators between bulk packaging and the environment can be used to collect relevant heat hazard parameters. The results of the analysis are directly related to the storage and transportation safety of the 2,2′-Azobis(2-methylpropionitrile). Finally, a series of evaluation models about the thermal safety of initiators are constructed and analyzed by simulating the runaway modes of the 2,2′-Azobis(2-methylpropionitrile) at different temperatures.

Di-tert-butyl peroxy-hexahydro terephthalate (HTP-65W), a newly developed organic peroxide, has been used in manufacturing acrylonitrile–butadiene–styrene copolymer and as an initiator in the polymerization. However, few studies focus on the thermal hazards of HTP-65W. The purpose of this study was to investigate the thermal decomposition phenomenon of HTP-65W under different conditions via calorimetric technologies and simulation. According to simultaneous thermogravimetric analyzer curves, two mass loss stages were detected at about 79 °C and around 64–72% mass loss happened in the first stage. Furthermore, the real view system was used to observe the apparent physical phenomenon like color and state change in HTP-65W during the reaction. Utilizing accelerating rate calorimeter and adiabatic kinetic method, the exothermic phenomena occurred at around 75 °C. The apparent activation energy (Ea) and rate constant of reaction under adiabatic conditions were 172.0 kJ mol−1 and 4.0 × 1025 mol L−1 s−1. Through differential scanning calorimetry and kinetics simulation, an exothermic peak appeared between 87 and 168 °C caused by the thermal decomposition of HTP-65W, and the Ea calculated using Flynn–Wall–Ozawa and Friedman methods were 143.4 and 128.4 kJ mol−1, respectively. To prevent thermal loss prevention accidents, time to maximum rate under adiabatic condition was obtained as 24 h under 63.9 °C and self-accelerating decomposition temperature was 61 °C for 50 kg package size of HTP-65W. Results of this study can support to prevent the potential thermal hazards of HTP-65W happened during storage, transportation, and manufacturing process.

1-Ethyl-2, 3-dimethylimidazolium nitrate [C2mmim][NO3] is a typical solvent for industrial applications. Under inappropriate temperatures, [C2mmim][NO3] may present a flammability hazard due to thermal decomposition. This study investigated the thermal stability and flammability of [C2mmim][NO3] via simultaneous thermogravimetric analyzer, homemade combustion test device (CTD) with high speed camera, and thermogravimetry coupled with Fourier transform infrared spectroscopy (TG-FTIR). The thermal decomposition of [C2mmim][NO3] was divided into two parts based upon the dynamic experiments, and the maximum operating temperature was determined to comprehensively estimate the thermal stability of [C2mmim][NO3]. CTD experiments indicated that [C2mmim][NO3] could produce intense combustion when heated. Further TG-FTIR experiments confirmed that [C2mmim][NO3] decomposed to produce a large number of flammable gases, such as ethylene, which might be the reason that [C2mmim][NO3] has prominent flammability.

Using batteries to convert chemical energy into electrical energy is one of the significant technologies that must be enhanced in the 21 st century. In the fuel battery development area, ionic liquids (ILs) are outstanding electrolytes for batteries. According to their thermophysical and phase equilibrium properties, ILs are widely used in different energy fields due to their diversity in the synthesis field. However, there are few detailed thermokinetic studies on ILs. To ensure the thermal safety of ILs in the process of creation, a commonly used IL, 1-butyl-3-methylimidazolium nitrate ([Bmim]NO3), was chosen for exploration. In this study, thermal decomposition characteristics were obtained by differential scanning calorimetry. The obtained data were input into the thermokinetic equation to determine the basic thermal hazards of [Bmim]NO3. In addition, based on thermal equilibrium theoretical models, the reaction kinetics and critical safety parameters were extrapolated for consideration. The influences of the sample mass and the overall heat transfer coefficient were simulated and discussed in 25.0 g and 50.0 g packages. The results showed that [Bmim]NO3 had a shorter TMRad and TCL (

The polymerization industry has existed for many years. The advancement of industrial technology is contributed to the related synthesis and application of enduring polymer operation. Organic peroxide (OP) initiators have been used and applied to practical industrial processes which may cause a runaway reaction due to their self-reactive property. OPs have been used for a long time and studied in the related literature. However, there are still emerging OPs that have recently been applied to these processes, and there are few related studies. To ensure the thermal safety of OPs in the process of production, transportation, and storage, the common OP initiator such as dicumyl peroxide (DCPO) was selected to be investigated. First, thermal decomposition characteristics under non-isothermal and adiabatic conditions of DCPO were acquired by differential scanning calorimetry. Second, combined calorimetry with pseudo-adiabatic and isothermal conditions can determine the process of thermal hazards and basic reaction patterns. The gleaned data can input into a mathematical model to evaluate the basic thermal hazards for DCPO, respectively. In addition, based on simulated thermal explosion models and kinetic parameters, hazardous properties of storage and transport can also be acquired. The results show that the DCPO has prominent hazard properties on thermal and explosive hazards in process conditions which should pay much attention to temperature during storage and transportation.

Ionic liquids (ILs) have very low volatility and are consequently considered as a green replacement to the organic solvents that have been widely used to date. The fire and explosion hazards of traditional organic solvents primarily depend on the combustibility of their vapors; therefore, ILs have been regarded as nonflammable for a long time because of their low volatility. However, recent studies have shown that ILs are flammable due to their thermal stability and consequently, the fire and explosion hazards of ILs limit their practical applications. The compound 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (abbreviated as [EMIM][Tf2N]) has been considered a potential candidate solvent for surfactant systems, but studies about the fire and explosion hazards of this IL are rare in the literature. In this study, the fire and explosion hazards of [EMIM][Tf2N] were explored in terms of different aspects. The auto-ignition temperature of [EMIM][Tf2N] was found to be 478 °C with an ignition delay time of 12.6 s. It was observed with the TGA/DSC system that the decomposition of [EMIM][Tf2N] was endothermic in a nitrogen atmosphere but exothermic in an air atmosphere. The dynamic TGA curves showed that the apparent activation energies were the same in both nitrogen and air atmospheres, but the dynamic DSC curves showed that the apparent activation energies were different in nitrogen and air atmospheres. The apparent activation energy inferred from the DSC curve in an air atmosphere was found to be the same as the apparent activation energy estimated by the Semenov theory of thermal ignition. Analysis of the gaseous decomposition products of [EMIM][Tf2N] by the TGA-FTIR system indicated that the exothermal effect in the air atmosphere was caused by the auto-ignition of acetylene (which is one of the gaseous decomposition products) and not by decomposition itself.

2,2′-Azobis (2-methylpropionate) (AIBME) is a new type of environmental-friendly oil-soluble azo initiator, extensively applied in the radical polymerization industry relying on its extraordinary thermal and physicochemical properties. Nevertheless, the special structure makes AIBME decompose easily under low ambient temperature with a tremendous amount of heat release. To qualify its thermal hazard and obtain the specific safety parameters such as time to maximum rate under adiabatic condition (TMRad) and self-accelerating decomposition temperature (SADT), differential scanning calorimeter (DSC), simultaneous thermogravimetric analyzer (STA), and accelerating rate calorimeter (ARC) were applied to analyze the thermal behaviors of AIBME while conducting the thermokinetic analysis and numerical curve fitting. The results indicate that AIBME decomposes at low temperature, and the SADT of AIBME in 25 kg UN package is 35.2 °C. Moreover, the temperature at TMRad = 8 h is determined at 51.6 °C using Townsend method. Compared with commercially used azo compounds, such as 2,2′-azobisisobutyronitrile (AIBN) and 2,2-azobis(2-methylbutyronitrile) (AMBN)), the predominant heat of decomposition, more gaseous degradation products, quicker heat release rate, and lower decomposition temperature make AIBME more hazardous during production, storage, and transportation. The results of this study can provide the references for the process safety assessment and the design of appropriate safety system in scale-up applications with the wish to avoid the occurrence of AIBME involved accidents.

Severe fire and explosions are frequent phenomena during handling of organic peroxides that are promoted supremely by conditions such as chemical impurities and thermal instability. As an initiator in the polymerization process, cumene hydroperoxide (CHP) has wide usage in the chemical process industry. This violently reactive chemical is studied here experimentally using differential scanning calorimeter (DSC), an isothermal mode of operation that can access the thermal hazards in the decomposition of CHP alone and later mixed with products following an autocatalytic reaction scheme. Importantly, DSC-evaluated thermokinetic parameters such as reaction enthalpy (ΔHd), time to maximum rate (TMRiso), and maximum heat flow (Qmax) were estimated to ascertain the degree of thermal hazard under various transportation and storage temperatures. The Heat-Wait-Search mode of accelerating rate calorimeter has been used to investigate decomposition kinetics parameters data under an adiabatic condition. Data such as initial exothermic temperature (T0), self-heating rate (dT/dt), pressure rise rate (dP/dt) and pressure–temperature profiles help to gauge the runaway reaction hazard of CHP alone and then mixed with its products to support the autocatalytic model of exothermic decomposition. The curve fitting data indicated that activation energy had reduced from 245.4 to 236.7 and 242.3 kJ mol−1, when CHP was mixed with acetone or dicumyl peroxide, respectively. The decrease in activation energy for autocatalytic material thermal decomposition reaction is depicted here with various experimental findings and mathematical analysis.

Azo compounds, which are commonly used in radical polymerization reactions, readily demonstrate their self-reactive properties. Because of their sensitive thermal decomposition properties, azo compounds have been responsible for many accidents. To avoid unexpected thermal decomposition in the workplace, information about the thermal stability and other properties of azo compounds should be provided to on-site personnel in industries that use these materials. In this study, the target substance, 2,2′-azobis-(2,4-dimethylvaleronitrile) (ABVN), is shown to have a higher reactivity than other azo compounds, and its thermal decomposition characteristics are discussed based on a literature review and results from differential scanning calorimetry (DSC) and accelerating rate calorimetry (ARC). A thermokinetic analysis of ABVN is conducted using DSC and ARC data. The results can provide process-control data and explain the effects of thermal runway for ABVN. In addition, based on applied numerical methods, critical runaway temperatures, stable temperatures, and the required heat dissipation rate for the prevention of the thermal runaway reactions are calculated using a process deviation analysis. The results show that the reactant quantities and the process parameters must be strictly controlled to achieve the desired reaction.

Coal, a flammable substance, is affected by spontaneous weathering and can be hazardous when exposed to thermally unstable conditions. Over the past few decades, numerous chemical disasters involving coal have occurred, resulting in many deaths. Therefore, strategies for the prevention of such disasters must be implemented to ensure human safety, avoid financial losses, and minimise adverse environmental effects. This study determined the thermal safety parameters and thermal hazards of lignitous and long flame coal by using thermogravimetry and differential scanning calorimetry. The characteristics of the functional groups in coal and treated coal were observed through Fourier transform infrared spectrometry. The structures of coal and coal treated with an ionic liquid, namely 1-butyl-3-methylimidazolium, were observed through scanning electron microscopy. Finally, theoretical kinetic models were applied to calculate thermokinetic parameters and identify the degree of thermal hazard present during periods of thermal instability. The results revealed that 1-butyl-3-methylimidazolium nitrate considerably reduced the probability of coal spontaneous combustion and the degree of hazard for long flame coal. Therefore, this ionic liquid could serve as an effective inhibitor of spontaneous combustion in long flame coal.

In the study, agricultural waste bagasse was used as a bio-based flame retardant for reducing the flammability of epoxy. Specifically, an interpenetrating network (IPN) was formed through a ring opening reaction between the hydroxyl functional group of bagasse and the epoxy group of triglycidyl isocyanurate (TGIC), forming Bagasse@TGIC. Next, 9, 10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide (DOPO) was mixed with Bagasse@TGIC, inducing a reaction between the active hydrogen of DOPO and the epoxy group of TGIC, ultimately forming Bagasse@TGIC@DOPO with an IPN structure. Finally, the novel flame retardant was added to epoxy to create a composite. The integral procedural decomposition temperature (IPDT) of pure epoxy is 619 °C, after the introduction of the 30 wt% flame retardant, the IPDT of the resultant composite material increased to 799 °C, greatly increasing the thermal stability by 29%. After the addition of the Bagasse@TGIC@DOPO flame retardant, the limiting oxygen index increased from 21% for the pure epoxy to 29% for the composite, and the UL-94 rating improved from failing rating for the pure epoxy and V-0 rating for the composite. The Raman spectrum indicated that the addition of Bagasse@TGIC@DOPO IPN substantially increased the biochar yield during the burning process, increasing thermal stability. These results confirmed that the epoxy/Bagasse@TGIC@DOPO composite had substantial flame retarding effects.

Fish scales (FSs) are fishery wastes that can cause environmental pollution. This study aimed to solve this environmental problem. FSs were used as a flame retardant for polymer materials, making them valuable. Fish scales were combined with a commercial flame retardant, ammonium polyphosphate (APP), through synergistic effects to reduce the amount of commercial flame retardant. The use of FSs conforms to the concept of a circular economy and lowers costs by reducing the consumption of APP. Thermogravimetric analysis (TGA), integral procedural decomposition temperature (IPDT), pyrolysis kinetics, limiting oxygen index (LOI), the Underwriters Laboratories 94 (UL94) flammability test, scanning election microscopy, Raman spectroscopy, and energy-dispersive X-ray spectroscopy were used to determine the thermal properties, flame retardant properties, flame retardant mechanism, char morphology, and composition of the composites. The TGA results indicated that the addition of 40% flame retardant raised the char residue from 16.45 wt.% (pure EP) to 36.07 wt.%, IPDT from 685.6 °C (pure EP) to 1143.1°C, LOI from 21% (pure EP) to 30%, and UL94 classification from fail (pure EP) to V-0. These results suggest an increase in char residue, which indicates better protection of the polymer matrix material. The improvements in IPDT, LOI, and UL94 classification, which indicate greater thermal stability, lower flammability (from flammable to fireproof), and higher flammability rating (from fail to V-0), respectively, suggest that the composite material has favorable thermal properties and is less inflammable.

In this study, a composite flame retardant was created by combining fish scale (FS), fishery waste, and ammonium polyphosphate (APP), a commercially available flame retardant. The composite flame retardant was added to epoxy resin (EP) to form an EP/APP/FS composite that prevents burns and is environmentally friendly. The use of FS conforms to the concept of circular economy and lowers costs by reducing the consumption of APP. Thermogravimetric analysis (TGA), integral procedural decomposition temperature (IPDT), pyrolysis kinetics, limiting oxygen index (LOI), the Underwriters Laboratories 94 (UL94) flammability test, scanning election microscopy, Raman spectroscopy, and energy-dispersive X-ray spectroscopy were used to determine the thermal properties, flame retardant properties, flame retardant mechanism, char morphology, and composition of the composites. The TGA results indicated that the addition of 40% flame retardant raised the char residue from 16.45 wt% (pure EP) to 36.07 wt%, IPDT from 685.6 °C (pure EP) to 1143.1°C, LOI from 21% (pure EP) to 30%, and UL94 classification from fail (pure EP) to V-0. These results suggest an increase in char residue, which indicates better protection of the polymer matrix material. The improvements in IPDT, LOI, and UL94 classification, which indicate greater thermal stability, lower flammability (from flammable to fireproof), and higher flammability rating (from fail to V-0), respectively, suggest that the composite material has favorable thermal properties and is less inflammable.