A short guide to EP(D)M


At Keltan Elastomers we breathe, sleep and live EP(D)M, but we are well-aware of the fact that some visitors of this website might be pretty oblivious to what EP(D)M even means.

We'll explain it to you in two minutes: EP(D)M is short for Ethylene-Propylene Rubbers, this refers to two different kind of polymers: EPM en EPDM ("polymer" simply being a synthetic substance composed of many repeated subunits called "monomers").

  • EPM represents a copolymer from ethylene and propylene monomers; EPM is entirely saturated and therefore requires vulcanization by radiation or products that release free radicals, such as organic peroxides.
  • EPDM denotes a terpolymer based on three monomers: ethylene, propylene and a non-conjugated diene; EPDM grades have a residual unsaturation in the side chains and can therefore be cured with sulfur and accelerators. Its heat resistance is distinctly better than that of Natural Rubber, SBR and Butadiene Rubber. The molecules of both EPM and EPDM have a completely saturated hydrocarbon backbone, through which excellent ozone resistance and very good resistance to heat and oxidation are achieved.