Elastomer

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The term elastomer is often used interchangeably with the term rubber, and is preferred when referring to vulcanisates. Elastomer comes from two terms, elastic (describing the ability of a material to return to its original shape when a load is removed) and mer (from polymer, in which poly means many and mer means parts). They are amorphous polymers existing above their glass transition temperature, so that considerable segmental motion is possible. At ambient temperatures rubbers are thus relatively soft (E~3MPa) and deformable. Their primary uses are for seals, adhesives and molded flexible parts.

Elastomers are usually thermosets (requiring vulcanization) but may also be thermoplastic (see thermoplastic elastomer). The long polymer chains cross-link during curing and account for the flexible nature of the material. The molecular structure of elastomers can be imagined as a 'spaghetti and meatball' structure, with the meatballs signifying cross-links.

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List of elastomers

Examples of elastomers:

Natural Rubber
Polyisoprene
- Butyl Rubber (copolymer of isobutylene and isoprene)
Polybutadiene
- Styrene Butadiene Rubber or SBR (copolymer of polystyrene and polybutadiene)
- Nitrile Rubber (copolymer of polybutadiene and acrylonitrile), also called buna N rubbers
Chloroprene Rubber, polychloroprene, also called Neoprene
Silicone RTV
FKM Viton®, Tecnoflon®(copolymer of vinylidene fluoride and hexafluoropropylene)
Santoprene®
Fluorosilicone Rubber
EPM and EPDM rubber (ethylene propylene rubber, a copolymer of polyethylene and polypropylene)
Polyurethane rubber
Resilin
Polyacrylic rubber (ABR)
Epichlorohydrin rubber (ECO)
Polysulfide Rubber
Chlorosulfonated Polyethylene (CSM), (Hypalon®)
Polyether Block Amide (PEBA), (Pebax®)