Papers by Keyword: Thermal Decomposition

Abstract: New patterns of the complex influence of various parameters on the ignition temperature of magnesium, aluminum and zirconium particles in the products of thermal decomposition of pyrotechnic mixtures based on fluoroplastics have been established. Experimental and statistical models have been developed for the first time to predict the influence of controlled technological parameters on the ignition temperature of metal particles to form a database on the fire-hazardous properties of pyrotechnic products under external thermal effects.

Abstract: The burning process of limestones is an important process in the modern industries, which can be described in two parts, CaCO₃ decarbonation due to the thermal stress and formation of CaO crystalline structure. It was already observed that the different composition and structure of a raw material influence the transformation process and has affect on the chemical and mechanical properties on the formed lime. This study is focused on the characterization of the raw material (porosity, chemical composition, geological age and origin) and its effect on the burning process and the formation of CaO and its properties. The microstructure of studied material burnt at different times of isothermal load was observed by SEM and the reactivity test was measured and analyzed. The limestone with a more porous inner system was burnt faster and is inclinable to overburn at longer thermal load.

Abstract: Consideration was given to the issue of flammability during the thermal decomposition of synthetic materials used for the constructions to isolate the process equipment and building structures. The experimental research data obtained for the thermal decomposition of synthetic materials with the measurements of temperature as a function of the time of thermal radiation were given including a change in the mass and structure of the specimens of synthetic materials exposed to the thermal radiation during the fire. The obtained experimental data enabled the substantiation of the process of the thermal decomposition of synthetic materials depending on time and temperature and also a change in the mass of the specimens of synthetic materials before and after the tests.

Abstract: Consideration was given to the issue of the integrated evaluation of the flammable properties and factors of wooden products (Oriented Strand Boards, OSB and Wood Particle Boards, WPB) as basic flammable construction materials exposed to the action of fire. The experimental data obtained for flammable wooden products during the experiments carried out to define the dependence of temperature on the time of fire impact, to measure and substantiate the charring depth of wooden products, to determine degradation zones affected by fire and their sizes (area, width and length) and to compare a change in the specimen mass before and after the tests have been given. The experimental data confirm and substantiate the pyrolysis processes of wooden products during the fire spread.

Abstract: Consideration was given to the issues relating to safety conditions and security arrangements during the thermal decomposition of wood at the time of the fire in the premises of domestic buildings. The data of experimental investigations obtained for the thermal decomposition of wood were given with the measurement data of the concentration of toxic gases (СО, СО₂), oxygen (О₂), and temperature depending on time and fire spreading conditions in the premises. The studies were carried out by comparing the changes in the temperature of the solid flammable materials with time and the emission intensity of toxic gas (СО, СО₂) under the limited oxygen access at the time of the fire. The research data confirm those obtained for the gaseous atmosphere composition in the premises during the thermal decomposition of the solid flammable materials.

Abstract: From the microscopic point of view, combining experiment with simulation, the thermal decomposition mechanism of solid propellant was discussed. At first, the thermo gravimetric curves of HTPB film and propellant were studied based on DSC-TG thermal analysis experiment technology. The thermal decomposition process of propellant was simulated by establishing the physical model of meso-structure cell. The results show that the simulation is consistent with the experimental trend. The above research is helpful to further understand the thermal decomposition mechanism of propellant.

Abstract: Over the past decades, significant advances have been made in the development and research of gas separation membranes based on ionic liquids (IL) and their polymer analogs (PIL) for membrane separation of "acid gases" such as CO₂ and H₂S from gas mixtures. Polymers containing various amino groups are of great interest for the selective separation of acid gases from gas mixtures, since ammonia and its derivatives are used in conventional purification. In this work, we have synthesized a monomeric ionic liquid based on 4 vinylbenzyl chloride with included triethylamine by the Menshutkin reaction. Further, on its basis, polymer ionic liquids were obtained by the method of free radical polymerization, then an anion exchange reaction was carried out to replace the Cl anion with Tf₂N. To analyze the process of thermal pyrolysis of poly [VBTEA-Tf₂N] a pyrolysis-gas chromatography/mass spectrometer (Py-GC/MS) was employed in this research. The obtained materials, which are high molecular weight compounds, can be used to obtain polymer membranes of various architectures by traditional methods: both non-porous symmetric membranes and microporous asymmetric membranes.

Abstract: Owing to its remarkable mechanical, electrical and thermal properties, graphene has been a hot area of composites research in the past decade, including the field of energetic materials. Graphene has been widely applied in enhancing the physical properties of energetic materials, such as solid composite propellants. Through the way of adding different forms of graphene into the matrix of solid propellants, their thermal decomposition performance can be effectively improved. In this paper, we reviewed the status and challenges of the application of graphene in the thermal decomposition of composite solid propellant. Moreover, the main preparation methods and material structures of graphene are reviewed. We can conclude that graphene and its derivatives can enhance the catalytic effect remarkably, which can be attributed to the large specific surface area of graphene that makes the uniformly dispersed catalyst particles and the more catalyst active sites. Meanwhile, graphene possesses the high thermal conductivity, making the rapider heat diffusion, which can promote the decomposition reactions of the energetic components in solid propellants. Graphene and catalyst work synergistically in their thermal decomposition. More than this, the main methods to improve the thermal decomposition of energetic components of composite propellants and their effects on decomposition temperature reduction are systematically summarized, respectively.

Abstract: Thermally activated ozone gas (TAO) was demonstrated as an alternative technology to conventional spin-on carbon (SOC) stripping. The SOC stripping rate with ozone gas was found to be a function of substrate temperature and actual ozone amount calculated from the ozone flow rate and concentration. Furthermore, work function metal (WFM) stripping rate showed a high selectivity to SOC films, and the amount of oxidation TiN, which is a WFM metal, was also equivalent to conventional technology of SOC stripping. This TAO gas process can be used in clean tools, making it a promising integrated solution for SOC stripping followed by post clean.

Abstract: The thermal decomposition kinetics of polybutylene terephthalate (PBT) and flame-retardant PBT (FR-PBT) were investigated by thermogravimetric analysis at various heating rates. The kinetic parameters were determined by using Kissinger, Flynn-Wall-Ozawa and Friedman methods. The y (α) and z (α) master plots were used to identify the thermal decomposition model. The results show that the rate of residual carbon of FR-PBT is higher than that of PBT and the maximum mass loss rate of FR-PBT is lower than that of PBT. The values of activation energy of PBT (208.71 kJ/mol) and FR-PBT (244.78 kJ/mol) calculated by Kissinger method were higher than those of PBT (PBT: 195.54 kJ/mol) and FR-PBT (FR-PBT: 196.00 kJ/mol) calculated by Flynn-Wall-Ozawa method and those of PBT and FR-PBT (PBT: 199.10 kJ/mol, FR-PBT: 206.03 kJ/mol) calculated by Friedman methods. There is a common thing that the values of activation energy of FR-PBT are higher than that of PBT in different methods. The thermal decomposition reaction models of the PBT and FR-PBT can be described by Avarami-Erofeyev model (A₁).