Fluorocarbon Rubber (FKM / VITON)
Fluorocarbon Rubber (FKM / VITON), has the same carbon atom backbone of most elastomers, but has many of the hydrogen atoms that are normally attached to the chain replaced by fluorine atoms. The resulting rubber provides the best overall combination of resistance to fluids and heat, high environmental/ozone resistance. It has excellent low compression set and ageing characteristics. Its low temperature tolerance is the worst overall of any elastomer, and steam and some fluids can still attack it.
Silicone Rubber
Silicone Rubber are basically polydimethyl siloxane, This special structure does not produce elastomers with high levels of strength or other basic physical properties, but all the properties are much less sensitive to temperature changes. It has excellent flame, weather, ozone and electrical properties, resistant up to very high temperatures and flexible to very low temperatures. It has Poor tensile and abrasion resistance compared to other elastomers. Fluid resistance is generally poor. Cost can be moderately high to fairly expensive, and special processing is required.
Nitrile Rubber
Nitrile Rubber is another copolymer using butadiene, combined with acrylonitrile (which gives high polarity) in varying proportions depending on what properties are desired. The acrylonitrile content imparts oil resistance to the elastomer, and the more acrylonitrile used in the copolymer However, low temperature flex is impaired by increasing acrylonitrile concentration. It has excellent resistance to petroleum based oils and fuels, silicone greases, hydraulic fluids, water and alcohols. It has a good balance of working properties such as low compression set, high tensile strength, and high abrasion resistance, combined with a low cost. So it is used widely in seals, O-rings, hoses, etc.
Ethylene propylene diene Monomer (EPDM)
Ethylene propylene diene Monomer (EPDM), EPDM is yet another copolymer, These polymers have no double bonds in their main chain structure, which makes them immune to many forms of chemical attack that affect most elastomers.It has very good low temperature properties, tolerates high temperatures well. It has excellent resistant to water, steam, heat, weather & ozone, ultra violet. It does not resist most fluids well, with the exception in an aviation hydraulic fluid. It is used frequently as a blending polymer with other elastomers to improve aging and ozone resistance.
Neoprene
Neoprene, Neoprene is a commercial name for polymer comprised of polychloroprene. It is a general purpose elastomer. it has inherent strength, elongation, abrasion resistance, resilience, fatigue, low heat buildup, bond ability, and low temperature flexibility. However, because of the increased polarity, it is definitely superior in resistance to oils, solvents, heat, aging, weather and ozone. Poor resistance to aromatic hydrocarbons.