Study of the influence of temperature-time conditions of vulcanization on the properties of elastomer compositions

The article was devoted to the study of the influence of temperature-time conditions of vulcanization on the kinetic parameters of structuring of rubber compounds and the physical and mechanical properties of rubbers. The object of the study was an elastomeric composition based on natural rubber and containing a sulfur curing system. The investigated rubbers were obtained under various time conditions and temperatures of 143, 160 and 170°C. It was determined that with an increase in the vulcanization temperature, the values of the minimum torque decrease by 11.6-15.6%, and the maximum torque increase by 3.5-4.1%, at the same time the density of rubber cross-linking increases by 6.2- 7.5%. Analysis of the results of determining the physical and mechanical parameters of rubbers revealed that at a temperature of 143°C the vulcanization time does not significantly affect the elastic-strength parameters of rubbers and vulcanizates are characterized by the highest values of tensile strength both before and after thermal aging. It has been established that with an increase in the vulcanization temperature, side processes are activated, leading to a decrease in the elastic-strength properties of rubber (a decrease in tensile strength by 9.2-16.4% and elongation at break up to 7.2%). Vulcanizates obtained at 170°C are characterized by the lowest indicators of elastic-strength properties, hardness Shore A and rebound resilience, which is due to the density of the network and the nature of cross-links. The research results showed that when choosing the final vulcanization mode, especially for multilayer products, it is necessary to take into account not only the energy consumption in the production of finished products, but also the influence of temperature and time parameters on the complex of physical and mechanical properties of each component of the product.