Thermal Destruction Processes Research Articles

KINETIC CHARACTERISTICS OF THERMOLYSIS PROCESSES OF WASTE RUBBER PRODUCTS

In this paper, the kinetic parameters of various stages of the processes occurring during the thermal decomposition of waste rubber products are determined. To study the physico-chemical and chemical transformations occurring in waste samples of rubber products with temperature changes, a thermal analysis was carried out. It has been established that the processes of thermal destruction of the carbon component of rubber products are similar to the processes occurring during pyrolysis of solid natural combustible minerals, and conditionally consist of four stages. On the basis of the derivatogram, the temperatures of the endothermic minima were determined, and the temperatures of the processes were determined from the beginning of the peaks of the effects on the DTA curve. To determine the kinetic parameters of various stages of the process of thermal destruction of rubber products without air access, the Arrhenius law was used as the initial equation, which describes the dependence of the reaction rate constant on temperature. It is established that a first-order kinetic equation is acceptable for the process of thermal decomposition of waste rubber products during pyrolysis, activation energies and pre-exponential multipliers of each stage of thermal decomposition are calculated. The lowest reaction rate is observed in the temperature range of 510-780 °C, respectively, this stage is limiting and determines the rate of the process. Based on the results of thermal analysis, a method has been proposed and developed that allows to obtain a refined solid carbon-containing pyrolysis residue by calcining it at a temperature of 800-850 °C in an oxygen-free environment until the complete cessation of gas emission processes. The data obtained are necessary for modeling the pyrolysis process of rubber products on a production scale. Based on laboratory studies and experimental data obtained, it is possible to optimize existing pyrolysis plants for rubber waste. For citation: Makarevich E.A., Papin A.V., Cherkasova T.G. Kinetic characteristics of thermolysis processes of waste rubber products. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 5. P. 107-113. DOI: 10.6060/ivkkt.20246705.6937.

The influence of the mine dust mineral composition on the characteristics of thermal destruction processes

The article describes the results of comprehensive laboratory tests of mine dust samples taken from active mine faces in the Kuznetsk coal basin (Kemerovo region, Russia). The purpose of the experiments is to study the characteristics of thermal destruction processes in mine dust depending on its mineral composition. Based on the results of electron microscopy, the mineral composition of the dust samples under study was determined, and the quantitative relationships of the mineral phases composing the sample were assessed. Using thermogravimetric analysis the lower limits of thermal destruction intervals were established for samples of mine dust with different compositions and percentages of mineral inclusions. The practical significance of the results obtained is substantiated.

Физико-химические свойства суспензий на основе оксида алюминия и перспективы их применения

Cordierite blocks of a honeycomb structure with square cross-section channels are used as ceramic carriers for three-route automotive catalysts. Catalytically active layers are applied from suspensions based on γ-Al2O3, which is introduced into the internal volume of the carrier. The preparation of suspensions included impregnation of Al2O3 powder with solutions of Pt, Eu precursors, dilution with water, grinding to particles with an average size of 4 microns, setting acidity in the required range. The study of the physicochemical properties (point of zero charge, specific surface area, particle size, pore volume, average pore diameter) of a suspension prepared on the basis of aluminium oxide and modified with europium and platinum ions is relevant due to the possibility of using three-path catalysts in technology. The surface and porosity parameters were determined by low-temperature nitrogen adsorption/desorption. pHzcp values were determined by gravimetric titration, the pH of the points were in the range of 6.01-7.1, therefore, the specified acidity range should not be beyond these limits. The processes of thermal destruction of suspensions during heating were studied by thermal analysis. During the heating process from -100 to 250°C, a weight loss was observed throughout the heating process. Endothermic effects were discovered, corresponding to the melting of ice, evaporation of moisture, and decomposition of nitrogen-containing compounds. The greatest weight loss was observed in an aluminium oxide sample modified with europium and platinum ions (Eu,Pt/γ-Al2O3). Quantitative assessment of the forms of moisture bonds in the suspension was carried out using experimental dependences on weight changes of the TG sample and the rate of change in the DTG weight in the temperature range of 270-380 K. Based on the activation energy values, it was established that the mechanism of moisture release from the Eu,Pt/γ-Al2O3 differs from others. The calculated activation energies for the release of moisture was high (41-92 kJ/mol), which indicates the bound state of water in the structure of the solid phase. The suspension was applied to a ceramic catalyst base and annealed at 500 °C, information about the mechanism of moisture release during heating of the suspension will help to avoid a decrease in the specific surface area.

Influence of electric field on the thermal properties of PP+NC nanocomposites for environmental chemistry application

Using Differential Thermal Analysis (DTA) method the thermal-physical properties of nanocomposites PP+NC for environmental and environmental chemistry applications were studied and the thermal-destruction processes after aging in an electric field were determined. The influence of various external factors (strong electric field, electric discharge, temperature, radiation, etc.) on polymers and composites based on polymers penetrates into the deep layers of the matrix and leads to the destruction and reconstruction of the structure. Changes in the ratio of crystalline and amorphous phase occur due to the formation of an interlayer crystalline phase in the matrix. In this regard, the thermal properties of pure PP and PP+2.0% NC nanocomposites were investigated using the derivatographic method to study the influence of the electric field on the aging process, melting temperature, and crystallization rate and depolymerization process.

Development and Substantiation of Approaches to the Management of Sewage Sludge of Different Storage Periods

A widespread method of sewage sludge disposal is still simple storage in sludge lagoons. Subsequent thermal utilization is hardly possible because sludge properties change over time and energy content is reduced. Use as a soil conditioner in agriculture or landscaping is usually not possible due to high heavy metal contents. This paper describes a method in which a 10-year-old accumulated sewage sludge can be utilized as technical soil by mixing it with pyrolized fresh sewage sludge. For this purpose, physicochemical and toxicological characteristics of sewage sludge of different storage periods were identified, processes of thermal destruction of sewage sludge analyzed, toxicological characteristics of solid products of thermal sludge treatment determined, and the possibility of using the sewage sludge–pyrolysate mixture as technical soil was assessed. Results show that the gross calorific value of fresh and one-year stored sewage sludge is with approx. 15,000 kJ/kg dry basis sufficient to produce pyrolysate autothermally. It is also shown that when the pyrolysis residue is mixed with fresh or 1-year old sewage sludge, heavy metals can be immobilized and thus the leaching of heavy metals significantly reduced by up to 75%. The method described can thus be a possible option for recycling accumulated sewage sludge.

Plastic waste: assessment of the prosesses of its formation and management in the North-Western Black Sea Coast Regions

Plastic waste represents a specific component within the municipal solid waste structure because of the peculiarities of its formation, possibility of reuse and ecological consequences of environmental pollution. In particular, growing consumption of plastic is accompanied by a constant level of recycling (4-8%). This leads to accumulation of plastic waste in the environment. The article presents data on the content of plastic waste in the municipal solid waste of Ukrainian cities. According to the data the content of plastic waste within the municipal solid waste amounts to 10-12%. Plastic waste is mainly represented by polyethylene and polyethylene terephthalate (more than 60%). It was discovered that plastic recycling companies import almost a third of recycled materials from Europe, while almost 84% of plastic is still ends brought to landfills. The analysis of the situation with separate collection of the municipal solid waste in the North-Western Black Sea Coast Region (namely Odesa, Mykolaiv and Kherson Regions) indicates a low level of secondary raw materials extraction. It is also exacerbated by the fact that only 75% of the population receives services for centralized collection of the municipal solid waste. It is estimated that almost 160,000 tons of plastic waste were brought to the landfills of Odesa Region in 2019. This volume is equal to the workload of existing plastic processing enterprises of Ukraine. So, as exemplified by Odesa Region, the research aimed at assessing the resource potential of plastic waste by main categories and in terms of clustering of the region, in accordance with the Regional Waste Management Plan project. It also describes the environmental consequences of leaving waste plastic materials in the environment – contamination with microplastics and formation of persistent organic pollutants. Moreover, it indicates that the municipal plastic waste is a significant source for such substances formation during thermal and mechanical destruction processes taking place within a landfill's body or marine environment. The research analyzes the main reasons for a low level of plastic waste use in the region. One of them is a lack of conditions allowing the citizens to collect plastic waste separately from the rest of their waste.

Research the Thermal Decomposition Processes of Copolymers Based on Polypropyleneglycolfumaratephthalate with Acrylic Acid.

Kinetics of thermal degradation of polymeric materials is usually studied by weight loss at a constant temperature or during heating. Hence, the activation energy and other kinetic parameters of the thermal destruction process are determined. One of the fastest and most accessible methods for studying the kinetics of these processes is TGA. Weight methods of TGA do not provide an opportunity to judge the proportion of gaseous degradation products. This is especially true for processes associated with the release of hydrogen and other substances with low molecular weights, the accuracy of determining the amount of which by the weight method is low. Meanwhile, the study of the gas evolution process can provide additional information about the kinetics and mechanism of thermal destruction processes. Of great interest is also the joint study of the total weight loss and gas evolution during the polymer heating. Using mass spectrometry, IR spectroscopy combined with thermal analysis (TGA/DSC-IR and TGA/DSC-MS) we have defined product composition and thermal destruction kinetics. As a result of the TGA/DSC-MS study of gaseous products of thermolysis in nitrogen atmosphere, there were found products with 44, 45, 59, 60, 68, and 88 phr. Quite a similar pattern for p-PGFPh:AA copolymers is also observed in TGA/DSC-IR studies: the same products and the same temperature range. However, in contrast to the TGA/DSC-MS study, CO release was also recorded by this method (weak signal). Kinetic characteristics of the processes were determined based on Friedman, Ozawa-Flynn-Wall and modified NPC methods. Obtained values of the activation energy and thermodynamic characteristics make it possible to predict the composition of polymers, which make a significant contribution to the development of theoretical ideas about the features of the physicochemical properties of polymers.

МОДЕЛЮВАННЯ ПРОЦЕСІВ АЕРОДИНАМІЧНОГО НАГРІВУ І ПЛАВЛЕННЯ КОСМІЧНИХ ОБ’ЄКТІВ В АТМОСФЕРІ ЗЕМЛІ

The results of modeling the processes of thermal destruction of large-sized space debris objects due to aerodynamic heating and melting in the upper atmosphere are presented in order to determine the feasibility of using a combined method for their de-orbiting. The cylindrical and spherical models of space debris elements were considered to estimation of the parameters of thermal destruction. The guess, that melt layer which is formed on an object surface, is carried away by a running atmospheric flow, was assumed. The value of heat flux depends on the location on the body surface, thus, two cases were considered: stagnation point, where the heat flux is maximum, and the point on a flat surface. It is shown that the efficiency of destruction of cylindrical bodies (first stages of launch vehicles) depends on the
 angle of attack during object movement in the atmosphere. The most advantageous, to provide the maximum thermal load, are the angles of attack not less than 40°. At small angles of attack, the thermal load on the side surface is insignificant, which can lead to incomplete destruction of the object. Calculations also showed effective combustion of objects spherical shape (fuel tanks of upper stages in the atmosphere. The presented trajectories of deorbiting of space debris objects confirm the effectiveness of thermal destruction for reentry angles: 0°; 0,5°; 1,0°; 1,5°. At the same time, the melting rate increases when reentry angle is increasing. Complete thermal destruction (melting) of the discharge objects is possible for the structural material from aluminum alloys, in particular АМг6. This case takes place in aerospace design practice. Thus, the use of a combined method of deorbiting the large-sized space debris into the dense layers of the Earth's atmosphere is quite appropriate, because it provides the productive aerodynamic heating and thermal destruction in the atmosphere some objects like as used first stages of launch vehicles or fuel tanks, which are the most typical components of space debris

Combined Computational and Experimental Studies of Anabasine Encapsulation by Beta-Cyclodextrin.

The encapsulation of the famous alkaloid, anabasine, with β-CD was studied to obtain a more stable and bioavailable inclusion complex. Various in silico and experimental studies of the obtained β-CD-anabasine complex are presented. Firstly, molecular docking studies were conducted against the α, β, and γ cyclodextrins to explore which subclass is the best for encapsulation. The obtained results that pointed at β-cyclodextrin were further confirmed by five MD simulations and MM-PBSA studies. Experimentally, the spectral properties of the anabasine β-cyclodextrin complex were determined by FT-IR, 1H, and 13C-NMR spectroscopic methods. Additionally, the surface morphology of the anabasine β-cyclodextrin was investigated using a scanning electron microscope. Furthermore, the outputs of the thermographic measurements utilizing a differential scanning calorimeter were displayed. The activation energy of the reaction of thermo-oxidative destruction of the clathrate complex was calculated, and the kinetic parameters of the thermal destruction processes were decided using the Freeman–Carroll, Sharpe–Wentworth, Achar, and Coates–Redfern methods. The kinetic parameters of the thermal decomposition of the anabasine β-cyclodextrin were in agreement and verified the reliability of the obtained results. The obtained computational, spectral, morphological, and thermogravimetric results verified the successful formation of the anabasine β-cyclodextrin complex.

INFLUENCE OF LIQUID FOAMING AGENT DISTRIBUTION ON THE FORMATION OF FOAM GLASS POROUS STRUCTURE

It was shown that the use of liquid-phase foaming agents is promising for the synthesis of foam glass. The dynamics of the change in the glass particles size in the process of batch obtaining was studied. It was shown that additional grinding of glass powder particles occurs during the mixing process. The influence of the time of the batch mixing on the structure of the foam glass was investigated. It was shown that the density of the obtained foam glass is directly proportional to the batch mixing duration. Changes in the structure of the material associated with the processes of distribution of a liquid foaming mixture on glass powder particles during mixing and subsequent changes in the dynamics of the glycerol thermal destruction processes were described.

Development of Self-Shielded Flux-Cored Wires for Arc Welding of Low-Alloy Steels

Current aspects of the developing of modern self-shielding flux-cored wires composition for arc welding of low-alloyed steels are considered. Advantages and disadvantages of flux-cored wires of carbonate-fluorite, oxide and oxide-fluoride types of are shown in comparison. The effectiveness of gas shielding of molten metal at welding with self-shielding flux-cored wires of carbonate-fluorite type is analyzed considering the thermal properties of their cores. It is shown that to improve reliability of gas shielding at welding using the wires of this type it is important not only to ensure generation of sufficiently large volume of shielding gases at thermal destruction of the wire core, but also to control this process, providing gas evolution at all stages of heating and melting of the wire. The results of complex thermal analysis of the wire core mixtures containing, for example, lithium carbonate show substantially large heat losses for heating and melting of the wire core, which are accompanied by the development of energy-intensive processes of thermal destruction of core components. It is shown that the limitation of lithium carbonate content in the wire at the level of not more than 2 wt. % allows not only to preserve welding arc burning stability at the acceptable level but also to provide effective gas shielding of molten metal and easy separation of slag crust. The control of thermochemical reactions in the core is achieved by selection of its proper composition to ensure favorable melting of flux-cored wire and electrode metal transfer to the welding pool. Results of metallographic examinations of distribution and composition of non-metallic inclusions in metal of the welds made with wires of the oxide and oxide-fluoride types are presented. Main properties of the developed self-shielding flux-cored wires and recommendations on welding are given in conjunction with prospective fields of their application.

Особенности пожароопасных свойств семян подсолнечника, способов их хранения и тушения

The physicochemical and fire-hazardous properties of sunflower seeds are considered, the peculiarities in the manifestation of the propensity of the product in violation of storage conditions and regimes (high humidity, temperature, high weeds, increased acid number of raw materials and, as a consequence, the manifestation of the vital activity of microorganisms and insects) to self-heating and spontaneous combustion are revealed. Under favorable conditions of heat accumulation and air inflow, spontaneous combustion can turn into open. This is especially typical for the processes of thermal and thermo-oxidative destruction of sunflower seeds enriched with oil, and because of the high well content, also with oxygen in the air. In buildings of sunflower floor storage, fire extinguishing when detected by fire alarm systems is carried out with the use of water and water-based means. The most acceptable and effective way to suppress the burning of vegetable raw materials and compound feeds, and to safely unload it from granaries is the combined method.

Влияние группового состава темных кубовых остатков и условий их окисления на свойства битумных вяжущих

Bitumen is a complex and specific in its composition organic materials, the physicomechanical, chemical, adhesive and other properties of which significantly depend on their group composition and the ratio of hydrocarbon fractions included in them. These properties, in turn, are directly related to the composition of the feedstock, which is determined by the level (depth) of processing of oil shoulder straps and the methods of oxidation and compounding of refined products of different levels. This work evaluates the group composition of the initial bituminous raw material and its changes during oxidation under various conditions. The study showed that the oxidation process is dominated by the processes of thermal oxidative destruction, leading to the decomposition of fractions of saturated hydrocarbons into aromatic, resinous and partially aromatic fractions into asphaltenes prone to agglomeration. The results of the study expand knowledge about the development of the potential for regulating the properties of commercial bitumen and polymer-bitumen binders based on them by varying the composition of oil strands supplied for oxidation. The data obtained were used to optimize the production processes of LLC "BITUM", Salavat, for the purpose of large-scale production of commercial bitumen and PMB. The binders produced were used in 2018-2019 for the production of asphalt concrete and polymer-asphalt concrete mixtures and the device of coatings based on them in the Volga Federal District.

Innovative ways to control dust and explosion safety of mine workings

Ensuring dust and explosion safety during underground coal mining is one of the most important tasks of industrial safety and labor protection departments. The main method of preventing explosions of coal dust settled in mine workings is to process them with stone dust (rock dusting). The traditional methods of quality control of rock dusting include radioisotope, optical and chemical methods. To implement them, the devices are equipped with environmentally harmful radioactive elements, expensive optical sensors, desiccants and replaceable flasks with chemical reagents, which increases the cost of analysis and its duration. The measurement error of these devices is 10 % or more. The main purpose of the study is to develop and substantiate a new method for monitoring the dust and explosion safety of mine workings, which will be devoid of the disadvantages of the methods mentioned above. It is proposed to evaluate the quality of rock-dust distribution by a fundamentally new way – thermogravimetric. The method was tested on the dust of coal mines in Kuzbass and the Vorkuta basin, including dust samples taken in mines with actual explosions. The article presents the results of experimental studies of the processes of thermal destruction of coal and stone dust mixtures. The non-overlapping intervals of the thermogravimetric reaction are identified: moisture yield (35-132 °С); volatile matter yield from coal (380-580 °С); thermal degradation of limestone with carbon dioxide yield (650-850 °С). Methods and mathematical dependencies for processing significant and qualitative identification characteristics of thermogravimetric curves in determining the content of non-combustible components in a sample of mine dust are considered.

Thermal destruction of polymers: analysis of the process physicochemical parameters

This experimental study has confirmed that during thermal decomposition of polymeric waste samples at a temperature of 850 °C, without oxygen access, there is a 90 % drop in the mass of this waste with the release of a large volume of gaseous products. This feature should be taken into consideration in the engineering calculations of reaction chambers, reactors, and connecting gas pipelines. The analytical study was carried out by a method of thermodynamic analysis using the universal estimation system Astra (TERRA). It has been shown that with an increase in reaction temperature there is a change in the composition of the products of thermal destruction of polymeric waste by reducing the mole fraction of СН4 and increasing the proportion of Н2. The calorific value was calculated according to Mendeleev’s empirical formula. The experimental study (a pyrolysis-gas chromatography method) has confirmed the calculation results regarding an increase in the proportion of hydrogen in the gaseous products of destruction with an increase in process temperature. As a result, due to the lower volumetric heat of hydrogen combustion, the total caloric content of the synthesis gas obtained is significantly reduced. For the experiments, a laboratory installation of low-temperature pyrolysis of polymers with external supply of thermal energy was built, and synthesis gas was used as an energy carrier. At the experimental-industrial installation, by a low-temperature pyrolysis method, the synthesis gas of a stable composition with a lower heat of combustion of 24.8 kJ/m3 was obtained. The reliability of the results of the proposed estimation method to the results of instrumental measurements has been shown. Promising areas of further studies have been determined, including the optimization of processes of thermal destruction of chlorine-containing polymer waste; the effective use of hydrogen from the composition of the synthesis gas obtained.

RESEARCH OF THERMAL PROPERTIES OF UHMWPE BASED COMPOSITES AFTER EXPLOSIVE PRESSING

The thermal characteristics of the initial UHMWPE and its composites with QGP and MDF, as well as those obtained by explosive pressing (VP), have been investigated. It has been established that explosive pressing leads to hindering the processes of melting and thermal destruction, which may be associated with chemical interaction, the formation of inter- and intramolecular cross-links characteristic of this polymer. UHMWPE and its compositions with 3% CHP after VP have higher melting points of the crystalline phase, thermal oxidation and thermal destruction in comparison with the starting materials of similar composition. In the UHMWPE composition with 10% MDF, no increase in thermal properties after VP was observed, similar to the original fluoroplastic.

RESEARCH OF THERMAL PROPERTIES OF UHMWPE BASED COMPOSITES AFTER EXPLOSIVE PRESSING

The thermal characteristics of the initial UHMWPE and its composites with QGP and MDF, as well as those obtained by explosive pressing (VP), have been investigated. It has been established that explosive pressing leads to hindering the processes of melting and thermal destruction, which may be associated with chemical interaction, the formation of inter- and intramolecular cross-links characteristic of this polymer. UHMWPE and its compositions with 3% CHP after VP have higher melting points of the crystalline phase, thermal oxidation and thermal destruction in comparison with the starting materials of similar composition. In the UHMWPE composition with 10% MDF, no increase in thermal properties after VP was observed, similar to the original fluoroplastic.

Using the method of pyrolytic mass spectrometry in the study of biodegradable polymeric materials

The results of pyrolytic mass spectrometry studies of biodegradable polymeric materials based on polyolefins and segmented polyurethanes with various functional additives are summarized. The structure and composition of initial and after exposure in soil, climate chamber and after exposure to microorganisms (bacteria, yeast) composites are characterized. In the research presented, influence of acetates and complexonates of metals, including cobalt, copper and zinc, on the structural changes in the high pressure polyethylene (HPPE) occurring under the impact of factors such as temperature, humidity and UV-radiation is investigated. It was established, that samples of HPPE, modified by cobalt acetate and cobalt and copper complexonates are responsive and most sensitive to the action of above-mentioned physical factors. Investigation of a segmented polyurethanes (SPU) of a different chemical structure influenced by a factors, modeling of the environmental conditions was conducted. It was shown using pyrolytic mass-spectrometry method and monitoring of samples’ weight loss that under the influence of above-mentioned environmental factors in the SPU occurs processes, resulting to changing its micro heterogeneous structure. It is established that SPU having ester links in its structure and being exposured in soil for 120 days is predominantly attacked by microorganisms, then the main active factor appears to be soil’ pH value – after 300 days in soil with alkaline or acid solution SPU sample decomposes into a separate fragments. Features of the chemical structure of urethane polymers synthesized on the base of hydroxylated rapeseed oil (polyol) were examined. Analysis of the results showed that the macromolecular compounds obtained are segmented polyurethanes which thermal degradation occurs in two stages: hard blocks are destroyed at the first stage, while polyol part (soft blocks) decomposes at the second stage, allowing to identify the temperature area of polymer destruction and thus its temperature region of operation. It is shown that the most suitable from the viewpoint of environmental friendly is polyurethane composition containing more than 50% of polyol. Thermal mass-spectrometry (TMS) has been employed to investigate processes of thermal destruction of segmented polyurethane and it’s compositions filled by polysaccharides: starch, dextrin, chitosan. The features of thermal destruction for segmented polyurethane and related compositions before and after their storage in a soil have been determined. Application TMS is shown to permit the processes of biodegradation of polymeric materials to investigate.

Chemical cellulose-based fibers of decreased flammability

The studies reported here have made it possible to determine the optimal ways of fire protection, in which the samples of modified complexite have reduced flammability. The sample with the ions of molybdenum (VI), treated with phosphoric acid, had the highest magnitude of oxygen index among five modified samples of the fiber. This is the most fire-protected sample, which contains three types of flame retardants: nitrogen (amidoxime groups of complexite, phosphorus (treatment with phosphoric acid) and molybdenum (VI). The obtained data indicate the chemical interaction of flame retardant with complexite.The morphology of fibers and the process of their destruction are influenced by the introduction of flame retardants. Scanning electronic microphotographs show the existence of a morphological change of the surface at modification of the complexite samples with flame retardant. The introduction of flame retardant into complexite affects the process of thermal destruction of the samples in the air and argon media. At the same time, the introduction of molybdenum (VI) significantly reduces the thermal stability of fibers. It is likely that processes of thermal destruction can be catalyzed by metals both in the air medium and in the argon medium. The magnitudes of order of reaction of thermal decomposition at the transition from a fiber sample treated only with acids to the samples of complexite containing molybdenum (VI) decreases up to 0.38. At the same time, the values of activation energies E, kcal/mol, and the enthalpy of the process of thermal destruction of complexite DH, kcal/mole also decrease. The mechanical properties of fibers at the introduction of flame retardants into the fiber composition change insignificantly. Depending on the composition of flame retardants, rupture load decreases by 6–11 %, lengthening of the samples decreases by 6–16 %.Thus, there are some grounds to suggest that it is possible to create fibrous materials based on cellulose with predetermined properties of reduced flammability.

The Effect of Water on the Thermal and Thermooxidative Destruction Processes of some Polyheteroarylenes

The temperature-time modules of drying and heat treatment of polyetherketones and polyphenylene sulfides are revealed; which made it completely possible to get rid of sorption water and an upper limit noticeable worsens the thermal stability of polymers. The most vulnerable bonds in polysulfones to the effects of water at processing temperatures were found.