Common O-Ring materials that are SUITABLE for dynamic and static seal in the environment containing Methane include

• Buna-N (Nitrile): Buna-N, also known as Nitrile rubber, is a synthetic rubber copolymer of acrylonitrile (ACN) and butadiene.
• Chemraz: Chemraz combines the resilience and sealing force of an elastomer with chemical resistance approaching that of PTFE.
• Epichlorohydrin: Epichlorohydrin (ECO) has properties similar to nitrile rubber but with better heat and oil resistance as well as better low temperature flexibility.
• Fluorocarbon: Fluorocarbon elastomer (FKM) material is also known by its tradename VITON or Fluorel.
• Hypalon: Hypalon is the traenme of a clasof Chlorosulfonated Polyethylene (CSM).
• Kalrez: Kalrez is the tradename for a perfluoroelastomeric material.
• Hydrogenated Nitrile: Hydrogenated Nitrile Butadiene Rubber (HNBR) is also known as Highly Saturated Nitrile (HSN).
• Virgin Teflon: Because Teflon is a hard plastic rather than a stretchy elastomer, it is uncommon to see an o-ring that is made entirely of Teflon.
• Vamac: Vamac is the tradename of a class of Ethylene Acrylic elastomer (AEM).

The O-Ring materials below are USUALLY SUITABLE for static seal in the environment containing Methane.

• Neoprene: Neoprene is a homopolymer of chlorobutadiene (CR).
• Polyacrylate: Polyacrylate (ACM) is a class of copolymer of ethyl and acrylates.
• Polysulfide: Polysulfide was one of the first commercial synthetic elastomers.

The following O-Ring materials are SOMETIMES OK for static seal but not for dynamic seal in the environment containing Methane.

• Millable Polyurethane: Millable Polyurethane rubber is made from both polyester and polyether polyols.

O-Ring materials that are NOT SUITABLE for using in the environment containing Methane include

• Butyl: Butyl (IIR) is a synthetic rubber, a copolymer of isobutylene and isoprene.
• Ethylene-Propylene: Ethylene-propylene (EP) is a copolymer of ethylene and propylene.