Lawrence R. Sita

CCB seminar presentation by Dr. Lawrence R. Sita, University of Maryland.

Talk title: "Molecular Catalysts for Green, Sustainable (and Commercially-Viable!) Technologies"

Abstract:

New paradigms are required that have the potential to dramatically change the range and pace at which specialty polyolefins can be discovered and commercialized. In this regard, we have been pursuing, within a living coordination polymerization system, the identification of dynamic fast and reversible bimolecular processes that are competitive with chain-growth propagation as a means by which to establish mechanistic control

points that can provide external control over the relative rates of these processes in such a fashion that a near continuum of different polyolefin grades between two different limiting stereochemical microstructures, co-polymer compositions or polymer architectures can be generated with a high degree of precision from a single catalyst.  When combined with living coordinative chain-transfer polymerization (LCCTP) in which an excess of a main group metal alkyl species is added that can serve as ‘surrogate’ chain-growth sites, which appear to propagate at the same rate as the active centers, practical (commercial) production of a broad range of specialty ‘precision’ polyolefinmaterials can now be brought closer to realization. This talk will focus on the results of our recent efforts made towards achieving this goal.

Relevant Selected References:

(a) Sita, L. R.

Angew. Chem. Int. Ed. 2009, 48, 2464-2472

(b) Zhang, W.; Sita, L. R.

J. Am. Chem. Soc. 2008, 130, 442-443.

(c) Zhang, W.; Wei, J.; Sita, L. R.

Macromolecules, 2008, 41, 7829-7833