Butyl rubber also known as polyisobutylene and PIB (C4H8)n is a synthetic rubber, a homopolymer of 2-methyl-1-propene. Polyisobutylene is produced by polymerization of about 98% of isobutylene with about 2% of isoprene. Structurally, polyisobutylene resembles polypropylene, having two methyl groups substituted on every other carbon atom. It has excellent impermeability, and the long polyisobutylene segments of its polymer chains give it good flex properties. Polyisobutylene is a colorless to light yellow viscoelastic material. It is generally odorless and tasteless, though it may exhibit a slight characteristic odor.
Ethylene Propylene Diene M-Class Rubber
EPDM rubber (ethylene propylene diene Monomer (M-class) rubber), a type of synthetic rubber, is an elastomer which is characterized by wide range of applications.The E refers to Ethylene, P to Propylene, D to diene and M refers to its classification in ASTM standard D-1418. The M class includes rubbers having a saturated chain of the polymethylene type. The diene(s) currently used in the manufacture of EPDM rubbers are DCPD (dicyclopentadiene), ENB (ethylidene norbornene) and VNB (vinyl norbornene).
Nitrile butadiene rubber (NBR) is a family of unsaturated copolymers of 2-propenenitrile and various butadiene monomers (1,2-butadiene and 1,3-butadiene). Although its physical and chemical properties vary depending on the polymers composition of nitrile (the more nitrile within the polymer, the higher the resistance to oils but the lower the flexibility of the material), this form of synthetic rubber is generally resistant to oil, fuel, and other chemicals.
Polybutadiene is a synthetic rubber that is a polymer formed from the polymerization of the monomer 1,3-butadiene. It has a high resistance to wear and is used especially in the manufacture of tires. It has also been used to coat or encapsulate electronic assemblies, offering extremely high electrical resistivity.