EPDM rubber is a ternary copolymer of ethylene, propylene, and non conjugated dienes.
Dienes have a special structure, where only one highly active double bond participates in the copolymer reaction, while the remaining less active double bond remains as an unsaturated point on the copolymer molecular chain for sulfur vulcanization. The main chain of EPDM rubber is saturated, which makes it resistant to heat, sunlight, and ozone. EPDM rubber is essentially non-polar, resistant to polar solutions and chemicals, with low water absorption and good insulation properties.