Polyolefin polymers have been an important part of daily life for variety of applications since the reported lab-scale process by Carothers in the 1930s1 and commercial process introduction by ICI in the 1940s.2 Most of the polyolefin polymer development since the 1940s can be referred back to the advent of novel catalyst chemistries and processing technologies. Ziegler3-Natta4-based catalyst chemistry dominated most of the commercial polyolefin manufacturing processes, including polypropylene, polyethylene and alpha-olefin5 copolymers until the 1980s.
The use of metallocene (zirconium)-based catalyst systems enabling higher comonomer incorporation with narrower molecular weight distribution to produce isotactic and syndiotactic polypropylene polymers6-7 opened several new markets for polyolefins in the mid-1980s. Further development in olefinic polymers was based on metallocene catalyst technology and constrained geometry catalysis technology (such as the one introduced in the last decade), enabling high activities for ethylene and alpha-olefin copolymerization and resulting in long chain branching, controlled monomer distribution and, thus, improved elastomeric and processability characteristics.8-11