EPDM rubber (ethylene propylene diene monomer (M-class) rubber), is an elastomer which is characterized by a wide range of applications.
The M refers to its classification in ASTM standard D-1418. The M class includes rubbers having a saturated chain of the polymethylene type.
The ethylene content is around 45% to 75%. The higher the ethylene content the higher the loading possibilities of the polymer, better mixing and extrusion.
Peroxide curing these polymers give a higher crosslink density. This is very much influenced by their molecular structure. The dienes, typically comprising from 2.5% up to 12% by weight of the composition, serve as crosslinks when curing with sulphur and resin, with peroxide cures the diene functions as a coagent, which provide resistance to unwanted tackiness, creep or flow during end use.
EPDM exhibits satisfactory compatibility with fireproof hydraulic fluids, ketones, hot and cold water, and alkalis, and unsatisfactory compatibility with most oils, gasoline, kerosene, aromatic and aliphatic hydrocarbons, halogenated solvents and concentrated acids.
The main properties of EPDM are its outstanding heat, ozone and weather resistance. The resistance to polar substances and steam are also good. It has excellent electrical insulating properties.