The evolution of new generaton 'single-site' Ziegler-Natta polymerization catalysts

Abstract

Since the discovery of stereospecific polymerization of olefins by K. Ziegler and G. Natta in 1955, tremendous developments have occurred in the area of designing polymerization catalysts. Rapid advances in organometallic chemistry research practised both at academic and industrial laboratories throughout the world have led to the emergence of new generation olefin polymerization catalysts and polyolefin products. The purpose of this article is to highlight some of the major events that have occurred in the area of Ziegler- Natta catalysis and to illustrate the contributions of organometallic chemistry in the exciting story of the evolution of well-defined, 'single-site' metallocene catalysts. The developments in the mechanistic understanding of key steps of polymerization processes such as generation of active species, chain propagation and chain termination emerging from organometallic modeling studies are also highlighted. Also, the recent discovery of late transition metal olefin polymerization catalyst systems and its implications for further research in Ziegler- Natta catalysis is described.