Studying the Stability of Ethylene—Propylene Rubbers under Thermocycling in Different Working Media

The change in the properties of ethylene–propylene SKEPT-40- and SKEPT-50-based rubbers under thermocycling in air and a medium of DOT-4 brake fluid within a temperature range from –50 to +50°C has been studied. It has been shown that SKEPT-40-based rubber specimens have a higher degree of retaining the strength characteristics, whereas SKEPT-50-based specimens have a higher degree of retaining the hardness and relative elongation. The frost resistance of ethylene–propylene rubbers in DOT-4 medium is much better preserved as compare to exposure in the air medium due to their good stability in this medium and its plasticizing effect. The contribution of ultra-high-molecular-weight polyethylene (UHMWP) to the stabilization of both the physicomechanical properties and frost resistance of ethylene–propylene rubbers has been established.