Ethylidene norbornene

Ethylidene norbornene (ENB) is a chemical compound. It is a diene, a chemical with two alkene double bonds, related to the polycyclic compound norbornane. Ethylidene norbornene is used as a comonomer to make EPDM rubber, a strong synthetic rubber.

 Polymerisation 
Polymerisation of ENB is very regioselective. Ring strain makes the double bond of the norbornene more reactive. This bond reacts with Ziegler–Natta catalysts and metallocenes, but steric hindrance stops the ethylidene group from reacting. This means that ENB polymers and copolymers have double bonds as side groups on a saturated polymer backbone.

 Sources 

Category:Monomers
Category:Dienes
Category:Bicyclic compounds
Category:Hydrocarbons