EPDM

EPDM, or ethylene propylene diene monomer, is a synthetic rubber produced by copolymerizing ethylene and propylene with a nonconjugated diene monomer to enable vulcanization. The diene component is typically ethylidene norbornene (ENB), dicyclopentadiene (DCPD), or cyclopentadiene, and the amount is adjusted to balance processability, elasticity, and cure characteristics. A related polymer called EPM (ethylene propylene rubber) lacks a diene and is more difficult to vulcanize with sulfur.

EPDM is renowned for its resistance to heat, ozone, UV light, and weathering, along with excellent low-temperature flexibility and good electrical insulation. It resists steam and hot water and shows compatibility with many acids and bases, making it suitable for outdoor, HVAC, and automotive sealing applications. The material has low permeability to water vapor and forms effective seals. Its limitations include poor resistance to hydrocarbons, oils, fuels, and many solvents, and it can swell in contact with nonpolar solvents. Typical service temperatures range from roughly -50°C to 120°C, with some grades rated beyond these bounds.

Manufacture involves emulsion or solution polymerization, followed by compounding with fillers, antioxidants, and curing systems. Vulcanization is usually sulfur-based or peroxide-based, with peroxide cures offering improved heat and oil resistance at the expense of some elasticity. Common applications include roofing membranes, automotive weatherstripping and window seals, gaskets, hoses for hot water or steam, electrical insulation, and pond liners.

EPDM products are durable and long-lasting; end-of-life management varies by region, with recycling and reclaim options available where facilities exist.