| abstract |
The present invention generally relates to the use of certain ruthenium and osmium complexes that are substantially inactive at a first temperature (preferably about room temperature) but become progressively more active at a higher second temperature. This difference in reactivities allows the reaction mixture to be formed and manipulated at the first temperature until polymerization is desired. When appropriate, the reaction mixture is heated to a suitable temperature (preferably greater than 50 DEG C.) to activate the catalyst and to initiate polymerization. Because both the initiation and the rate of polymerization may be controlled with temperature, the inventive methods are especially suitable for ring opening metathesis polymerization ("ROMP") reactions and for molding polymer articles that require extended pot-lives. |