| Summary: | The paper considers the influence of the introduction of aluminosilicate microspheres on value of the Payne effect, rheometric, physico-mechanical thermophysical and fire-heat-shielding properties of the elastomer compositions used in the thermal protective coatings based on ethylene-propylene rubber. It was found that partial sorption of vulcanization accelerators and sulfur can occur on the surface of microspheres, followed by their desorption at the vulcanization temperature. This is confirmed by the appearance of a second peak on the vulcanization rate curve. The use of hollow aluminosilicate microspheres in the composition of elastomeric fire-heat-shielding coatings makes it possible to increase the efficiency of these compositions by reducing the thermal conductivity and density of the article while saving the optimum level of physico-mechanical properties. In accordance with the proposed mechanism for the interaction of the polymer matrix and microspheres, additional crosslinked structures are formed within the rubber matrix. An increase in the content of microspheres leads to an increase in the filler-filler interaction, which leads to a relative increase in thermal conductivity. However, the thermal conductivity of compositions containing relatively large amounts of the microspheres is still lower than that of the control. The introduction of microspheres slows down the heating of the sample during high-temperature tests, while reducing the loss of mass and the rate of linear combustion.
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