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Research Projects: Click images for more information
- Organometallic Initiators for Controlled Polymerization Reactions
The Scheme below shows how the reaction cycles are coordinated. Compound 1 is well known for its ability to incorporate 1-alkenes into a growing polyethylene chain. Compounds 2 and 3 were developed in our laboratories during our studies on how Lewis acids activate a metal center by attachment to a site removed from monomer trajectory. Compound 2 dimerizes ethylene to 1-butene, while 3 is a precatalyst for the conversion ethylene to a distribution of 1-alkenes. The presence of 2 gives rise to 1-butene, which ultimately is incorporated by the titanium site into a polyethylene chain to yield ethyl branches. Similarly, the distribution of 1-alkenes generated by the catalyst derived from 3 produces in the polymer chain a distribution of branches of varying lengths. The three catalysts work together to provide a branched polyethylene structure from ethylene alone, which is not possible to attain using any two catalysts. The resulting polyethylene materials have a range of useful bulk physical properties |
