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The water resistance of cotton textile materials impregnated with SiO2 sols obtained on the basis of liquid glass was studied. Experimental coatings on fabrics were prepared by the bath method. After applying each coating layer and removing excess ash, the experimental samples were dried at (60–80) ºС. Fabric samples impregnated with sol SiO2 were immersed in containers with distilled water maintaining the same sample/water ratio. The fire-retardant properties of the coatings were determined after standing in water for 2–72 hours. The degree of destruction of coatings during hydrolysis was studied by determining the optical density of the hydrolyzate above the surface of the samples using the spectrophotometric (KFK-2) method. Fire-resistant properties were determined at a laboratory installation for fire tests. Under the influence of water, partial hydration of the surface of the silica coating occurs, which does not lead to its destruction. The presence of a layer of adsorbed water molecules on the surface of the coating is the reason for an additional increase in the fire-retardant properties of the samples. It is shown that the degree of homogeneity of the SiO2 sol affects the resistance to hydrolysis of the gel coatings. Low-concentration SiO2 sols (8 %), which are characterized by high fluidity and have a long service life, have a predominant effect. The long-term effect of water provides an increase in the fire-retardant properties of impregnated samples in comparison with non-impregnated fabric samples. The concentration and degree of homogeneity of the SiO2 sol have a predominant effect on the flame retardant properties. The surface layer of flame-retardants prevents the final burning and smoldering of the samples after removing the fire source, but does not significantly affect values of flame-retardant properties.

The effect of fire-retardant compositions based on organo-inorganic SiO2 sols without the use of flame retardants on increasing the fire resistance of cotton-containing textile materials has been studied. Previous studies have shown that the combined use of silicate coatings and flame retardants of simple structure prevents the ignition of impregnated samples of cotton-containing fabric and the proposed chemistry of this process. These studies did not use flame retardants to obtain more information on the effect of the composition and concentration of experimental organo-inorganic SiO2 sols on the fire resistance of treated tissues. The compositions were prepared by the sol-gel method using a technical product – liquid glass – with a silicate modulus of 2,5 and acetic acid solution. The influence of sols concentration in terms of conditioned SiO2 on their rheological features has been studied. It was found that the optical density, fluidity and survivability of experimental sols depend on the concentration of SiO2 in the sol. The compositions were applied to the fabric by the bath method in layers: each layer of the coating was fixed on the surface of the fabric by thermal shock in an oven at temperatures of 80-100 °C. Untreated cotton fabric caught fire under the influence of fire after 7 seconds. Impregnated tissue samples did not ignite under the action of fire, but gradually charred. To determine the effect of coating thickness and SiO2 concentration in the sol on the fire resistance of impregnated fabric samples, fire tests at a gas pressure of 0,2 MPa were performed for 8 s and the area of damage to the reverse side of the fabric was determined. Prolonged exposure to the flame resulted in a crack in the center of the charred spot. In the absence of flame retardants in the fire-retardant composition after removal of the fire source, decay was observed. The time for which a crack is formed in the sample under the action of fire was determined at the time of onset of tissue destruction. It is shown that in the case of using a sol of 10% concentration it is necessary to apply three layers of coating, which doubles the fire resistance (from 7 s for untreated fabric to 15 s for impregnated fabric), the start time of destruction increases 5 times (from 1 min to 5,5 min). The area of damage to the reverse side of the fabric not treated and impregnated with the experimental coating is reduced from 632 mm2 to 0, respectively.

The influence of the process of fire-retardant coating on textiles on the degree of fire protection of cotton and blended fabrics is investigated. Physical-chemical properties of impregnated samples of textile materials depending on the composition of ethyl silicate hydrolysates, concentration and content of diammonium hydrogen phosphate on fire resistance of impregnated samples, time of onset destruction and area of charring of samples after fire tests are analyzed. The obtained experimental data showed the need to build a mathematical model of the protective action of the gel coating based on the laws of heat and mass transfer, which under conditions of maximum simplicity and minimal artificiality takes into account the main processes from the external heat flow processes of heat transfer, thermal decomposition, evaporation and removal of mass, as well as to develop algorithms and software for computer modeling of the protective action of such a coating in conditions of constant or dynamic thermal exposure. A mathematical model of fire-retardant action of organosilicon coating on cellulose-containing fiber of fabric threads has been developed. It provides predictive estimates of fire safety parameters of textile materials, based on the level of thermal impact on the surface of the protected material.

The presence of melting temperatures oscillatory and stepwise changes for hydrocarbons four homologous series is demonstrated and analyzed. The oscillating dependence is manifesteds on the principle of «even-odd» molecules with different deviations from linearity. According to the working hypothesis, this is due to the presence of the matter smallest structural unit in the cluster form of with a certain coordination number. The oscillation of melting temperatures in hydrocarbons series is explained by the fact that clustering can occur both at the site of the final carbon in the molecule and at other carbons in the molecule chain, and this fact depends on the «even-odd» effect. Based on the known values of melting temperatures in homologous series, the clusters probable structure is assumed. It is shown that graphs for the calculated values of equivalent lengths of these clusters correlate with corresponding graphs for hydrocarbons melting temperatures. An approximation formula has been developed to predict melting temperatures of hydrocarbons based on the values of the equivalent length and the cluster molecular weight, which operates with an approximation coefficient of 0.997 and a mean deviation of 4.2 K.

The problem of development of technological principles of obtaining silica coatings on the basis of stable concentrated SiO2 sols on the basis of liquid glass is solved in the work. The composition was developed and SiO2 sols based on liquid glass of technical purity were obtained by mixing a solution of liquid glass and acetic acid. Experimental coatings on tissues were prepared by the bath method. After applying each coating layer and removing excess sol, the experimental samples were dried by heating in an oven at (60–80) ºС. The resulting silicic acid solution is characterized by pH5-6, has sufficient resistance to coagulation for about an hour. To improve the quality of impregnation of fabric threads with the composition, ethanol was added in the amount of 5 to 15 vol. %. The obtained compositions were examined by spectrophotometric (CPK-2) and microscopic (Digital Microscope S10) 1000x methods of analysis. The behavior of experimental sols in the induction period of maturation was studied and it was found that the viability of sols increases with increasing alcohol content. It is shown that small amounts of alcohol lead to a decrease in the buffer capacity of the composition and, accordingly, to a decrease in the viability of sols. The alcohol content of 15 vol. % significantly increases the survivability of the sol. The influence of alcohol content on fire-retardant properties of impregnated tissue samples was studied. It has been shown that regardless of the concentration of the SiO2 sol, 10 % ethanol must be added to the composition to improve the fire-retardant properties of the impregnated tissues. After the fire tests, the fabrics have a fairly dense structure, but all the threads have become much thinner. All samples did not lose their elasticity, the coating did not crumble. Given that the stability of impregnated fabric samples compared to non-impregnated samples increased 5–7 times, it can be concluded that the use of SiO2 sols based on liquid glass for fire protection of textile materials is promising.

Based on the generalization of research results on the processes of obtaining SiO2 sols using tetraethoxysilane and ethyl silicates, the main factors influencing the elasticity of silica coatings on cotton fabrics and their fire-retardant properties are considered. The possibility of forming covalent bonds between the functional groups of cellulose, gel coating and flame retardant layer is considered, which explains the strong fixation of a thin layer of coating on the fibers of the fabric and improve its fire protection. The use of the developed compositions for fire-retardant elastic coatings based on ethyl silicate allows to increase the time of complete burning of cotton from 30s (untreated fabric) to 600s (treated with binary coating).

The use of complex fire-retardant coatings based on ethyl silicate gel - diammonium hydrogen phosphate reduces the process of smoke formation during thermal exposure to treated tissue samples, which is promising for improving the fire safety of textile materials. The compositions are easy to obtain, they do not require specific processing conditions, do not contain toxic substances. This allows us to offer developed compositions for fire protection of textile materials used in facilities with a large number of people.

The paper considers the influence of the composition of the flame retardant composition on the change of fire-retardant properties of textile materials. Experimental samples of cotton fabric were impregnated with sol of ethyl silicate-40 obtained under conditions of acid-base hydrolysis. A solution of diammonium hydrogen phosphate was sprayed on the dried surface of the gel coating and dried again. The influence of the composition of the hybrid composition of the system of ethyl silicate gel - flame retardants on the fire-retardant properties of impregnated textile materials was studied, namely the time of onset of fabric charring, the area of damage to the reverse side of the fabric after the action of the kinetic flame for 8 s, as well as the time of onset of tissue destruction, which was determined at the time of the crack on the sample. It is shown that additional fixation on the surface of the hybrid coating of the ethyl silicate gel - diammonium hydrogen phosphate-urea system further increases the fire-retardant properties of the coating, but only under conditions of using small amounts of urea. It was found that urea acts as a conventional additive-modifier. It improves the properties of the coating in small quantities, and sharply worsens them if it used in large one. In connection with the composition of the hybrid coating was optimized for its effect on the area of damage (total and deep) and the time of onset of destruction of the samples, ie the time during which the crack formed on the fabric under the action of the flame. Small additions of 20% diammonium hydrogen phosphate solution and 10% urea solution increase the resistance of the textile material to the action of the kinetic flame by almost 12 times. It is shown that after long-term heat load (for 10 minutes) impregnated fabrics do not lose elasticity. Final burning and decay is not observed. Due to the fact that minor tissue destruction begins only after 10 minutes of action of the kinetic flame, the results made it possible to offer hybrid siliceous coatings for fire protection of rescue stretchers, which are designed to rescue the wounded from high-rise buildings during a fire.

The influence of the degree of homogeneity of the SiO2 sol on the duration of the induction period and the quality of fire-resistant coatings on textile materials was studied. The prospects of using IR spectroscopy as an express method for studying the phase composition of a gel coating, the degree of completion of the hydrolysis of an organosilicon component, and adjusting the parameters for obtaining a high-quality fire-resistant binary coating of a sol SiO2 - flame retardant system are shown.

Established the possibility of galvanochemical obtaining of a plating stronger than in case of chrome precipitation. Proposed precipitation of ternary alloy Co-Мо-W, which allows using the effect of synergism. Proposed and researched usage instead of sulphate-anhydride electrolyte – citrate-diphosphate and ammonia-citrate one. Achieved an increase in current efficiency of precipitated alloy and decrease in current efficiency of hydrogen, with respect to chrome precipitation, which increased safety of the galvanochemical industry. Selected the optimal ratios of components in citrate-diphosphate and ammonia-citrate electrolytes for ternary alloy Co-Мо-W precipitation. Determined the parameters of electrical effect for the galvanic process: constant current – j = 2–8 А/dm2, pulse unipolar current – j = 4–20 А/дм2. Achieved a high microhardness of this plating and high adhesion to base surface. Achieved greater safety of the galvanochemical technological process of ternary alloy Co-Мо-W application compared with chromium plating.