Polybutadienes cross-metathesis

Cross-metathesis of dimethyl hex-3-enedioate with polybutadiene containing 20-30% 1,2 units has also been studied, with similar results (Campistron 1986). 

The use of this last group of compounds in the synthesis of functional polymers as well as the use of group (iii) coreactants in the polymerization or copolymerization of cyclic olefins and in the cross metathesis of polydodecene and cw-1,4-polybutadiene has been pioneered commercially by the Huls company. A 80% ra 5-polyoctenamer is now commercially available under the tradename Vestenamer 8012. 

Polybutadiene is readily cross-linked by heating with 1% dicumyl peroxide for 10 min at 145°C. If the product is first extracted with C2CI4 to remove any non-cross-linked material and then placed in eontact with WCl6/EtA.lCl2/EtOH in C2CI4 at 45°C, it rapidly goes into solution (Hummel 1970 Kumar 1981). An added acyclic olefin assists this process but is not essential. It is clear that the network can be readily broken down by the occurrence of either intramolecular or intermolecular metathesis reactions. 

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