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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.