Investigation of the Effect of Fillers on the Properties of the Expanded Coke Layer of Epoxyamine Compositions

Intumescent fire-retardant coatings based on epoxy resins, compared to traditional fire-retardant compositions, have improved performance properties – high strength, chemical and atmospheric resistance, adhesion to many materials. However, unmodified epoxy polymers are combustible and to obtain IFR based on them, flame retardants and mineral fillers are added to their composition. Intumescent systems for flame retardant coatings based on epoxy oligomers (non-halogen-containing) usually consist of ammonium or ammophos polyphosphate as an acidic agent and a wide range of fillers, both inert and gaseous, or which are an additional source of carbon. Each component of the fire-retardant intimate coating in different ways affects the processes of coke formation, which determines the requirements for their choice. Thus, the aim of this work is to conduct experimental studies of the dependence of the characteristics of the expanded coke layer on the composition of the intumescent epoxyamine composition. The results of experimental studies of the effect of ammonium polyphosphate and binary mixtures of ammonium polyphosphate (APP) with aluminum hydroxide (AH), sodium tetraborate decahydrate (STD), titanium oxide TiO2 (TO), pentaerythritol (P), aerosil (A) and expandable graphite are presented (EG) on the multiplicity of expanding and weight loss of epoxy compositions at study temperatures of 350, 400 and 450°C. Studies have shown that the production of intumescent flame retardant coatings based on epoxy oligomers is possible provided they are filled with ammonium polyphosphate in an amount of more than 20 mass parts. The most effective in terms of expanding are additives titanium oxide and aluminum hydroxide in an amount of 20 mass parts, which allows to obtain intumescent fire-retardant coatings with a linear coefficient of expanding 30-32 and 24-27, respectively, throughout the range of temperatures. The obtained data are useful in the development of fire-retardant coatings based on epoxy oligomers.

ASPECTS OF DEVELOPMENT OF FIREPROOF COMPOSITIONS FOR STRUCTURES WITH TEXTILE FUEL PRODUCTS

The results of experimental studies on the effectiveness of fire protection of easily erected structures made of flammable textile products are presented. An analysis of the directions of use of easily erected structures made of flammable textile products indicates a steady trend towards an increase in their use during the temporary fulfillment of certain tasks of the Armed Forces of Ukraine and units of the. During the heating of such structures, ignition and rapid spread of fire are possible. The operating statistics for easily erected structures have found a low level of safety due to the use of natural fibers (e.g., linen, cotton and blends), which are highly sensitive to heat and fire. Reduction of combustibility and the development of non-combustible and non-combustible materials is one of the main directions for preventing fires and solving the problem of expanding the scope of these materials. Treatment with fire protection means significantly affects the spread of the flame, allows you to reduce the smoke-generating ability and heat release significantly. After the test, it can be seen that the sample of the textile material sustains spontaneous combustion for more than 5 s; sample damage is more than 150 mm. After the test, it is clear that the sample of textile material does not support self-combustion for no more than 5 s; sample damage is no more than 100 mm. The inhibition of the process of ignition and flame propagation for such a sample is associated with the decomposition of fire retardants under the influence of temperature with the absorption of heat and the release of incombustible gases (nitrogen, carbon dioxide), a change in the direction of decomposition towards the formation of incombustible gases and a hardly combustible coke residue. This leads to an increase in the thickness of the coke layer and inhibition of the heat transfer of the high-temperature flame to the material, which indicates the possibility of the transition of textile materials during processing with a fire retardant composition to materials that are non-combustible, which do not spread the flame by the surface.

Gasification Characteristics and Kinetics of Unburned Pulverized Coal in Blast Furnaces

Pulverized coal injected into a blast furnace (BF) burns incompletely in a very limited amount of time. A considerable amount of unburned pulverized coal (UPC) escapes from the raceway to the coke layer. The unburned pulverized coal reacts with CO2 in the coke layer, and this has a very significant impact on the operation of the BF. The gasification reaction characteristics of the UPC with CO2 were assessed by thermogravimetric analysis. The microstructure and specific surface area of the pulverized coal and UPC were characterized by scanning electron microscopy (SEM), and a specific surface area testing apparatus together with the Brunauer-Emmett-Teller (BET) method, respectively. The results showed that Qingding UPC requires a higher temperature to complete the gasification reaction. At the same heating rate, the Tm (maximum reaction rate temperature) of the Shenhua UPC is much lower and the reaction rate is larger than those of the Qingding UPC. An increased heating rate is beneficial for the gasification reaction of the two UPCs. The kinetics analysis results showed that the optimal mechanism function models for the Shenhua and Qingding UPCs are chemical reaction models. The apparent activation energies of gasification of the Shenhua UPC and Qingding UPC under different conditions were 269.89–223.41 KJ/mol and 266.70–251.54 KJ/mol, respectively.

Heatfireprotection Polymer Coatings on the Basis of EPDM-40 with Additives

Triple ethylene-propylene copolymers (EPDM) are used for the making of structural elements exposed to mechanical loads and are heat-resistant [1, 2], but their widespread use in aviation and shipbuilding equipment and other industries is limited due to Flammability. Double ethylene-propylene rubbers are practically limiting, and triple (EPDM), Dicyclopentadiene is used as the third component, due to the small content of double bonds in the side chains, have high heat resistance compared to diene rubbers [2], and therefore the issues of fire resistance of rubber-technical products based on them remain more and more urgent [3-7]. In [7] it is shown that if the values of the oxygen index (OI) and PP and EPDM are equal 17 % and 18.5 %, respectively, the coke numbers (CN) - 0 % and 0.5 %, and the copolymer is a PP/EPDM = 37,5/62,5 OI increases to 19.5% and CN up to 1.5 %. For copolymer PP / EPDM = 61.5 / 38.5 OI and CN are 21% and 3.4%, respectively, i.e. fire resistance in copolymers does not increase, which is an urgent problem. Polyolefins as it is shown in [7] and other works, at pyrolysis in soft conditions decompose practically without the rest, at thermal blows the mechanism of destruction changes and the carbonized rest is formed. The presence of cross-linked structures in the macromolecules of polyolefins also leads to the appearance of a carbonized residue. In work [8] the formulations of rubber mixtures resistant to wet chlorine, aqueous solutions of sodium hydroxide and sodium chloride, hydrogen, for the production of gaskets for electrolyzers and in [9] the effect of dithiophosphate accelerators on the complex properties of rubbers based on rubber grade EPDM-40. In [10] investigated the effect of a modified alumino-silicate intumescent microfiber filler kaolin microfiber (KMF) on the fire and heat protective properties (FHP) of vulcanizates based on ethylene-propylene-diene rubber EPDM-40. The compositions contained from 3 to 15 Weight Part (W.P.) KMV with a fractional composition of 25-110 microns and a fiber diameter of about 10 microns. As modifiers used a phosphorus boron containing oligomer (FBO), contributing to the increase of fireheat protective properties and multifunctional additive - hexachlor-p-xylene. It has been established that the modification of the kaolin microfiber leads to an improvement in the fire and heat protective properties at high temperature exposure: the rate of linear combustion decreases by 14%, the formation of the coke layer (CL) increases. It is shown that in conditions of erosion ablation, the fire-protective material has a 10 to 15% increase in tearing strength of CL, the time of onset of fire increases by 20-40% and the time of CL separation by 30%. In [ 11 ], the effect of HYPERLINK "https://translate.google.com/translate?hl=ru&prev=_t&sl=ru&tl=en&u=https://elibrary.ru/keyword_items.asp%3Fid%3D12826492" microcarbon fiber, a solution of FBO, HYPERLINK "https://translate.google.com/translate?hl=ru&prev=_t&sl=ru&tl=en&u=https://elibrary.ru/keyword_items.asp%3Fid%3D2483721" elastomers and HYPERLINK "https://translate.google.com/translate?hl=ru&prev=_t&sl=ru&tl=en&u=https://elibrary.ru/keyword_items.asp%3Fid%3D4285142" elastomeric materials on the fire-protective properties of EPDM-40 was investigated. The aim of the study was to investigate the processes of pyrolysis in the condensed phase, improving the properties of incombustibility and the creation of flame retardant rubber based on EPDM-40 for metal constructures.

The researches of high-temperature properties of iron materials in laboratory conditions

The aim of the study is to simulate in laboratory conditions the behavior of iron ore materials in the zone of softening-melting DP and drip flow using an integrated method developed at the Institute of Ferrous Metallurgy. It is shown that the widespread idea of the formation in the blast furnace of primary slag melt based on FeO takes place mainly in the initial period of slag formation and is true for low basicity iron ore materials. For pellets, the nature of the formation of liquid phases differs significantly from the agglomerate. Experimentally established changes in the composition of the slag melt as heating. It is shown that under the conditions of temperature and heat treatment of raw materials, each temperature has its own composition of the liquid phase. When the pellets are melted, the primary melt is formed in the temperature range of 1330–13600C, in which the proportion of primary slag is 16–25%. Melt from high-silicon lumpy ore is formed at high temperatures of 1490-15200С. The mass of the primary slag with 42-48% FeO is 4-8% by weight of iron ore materials. The main part of the melt hangs on the coke nozzle on the coke layer at temperatures above 16000C. Melts formed from mixtures of iron-containing materials, as a rule, have averaged characteristics. The observed patterns make it possible to predict the behavior and properties of multicomponent charge mixtures in a blast furnace.