English Abstract
Recent Developments of Organotransition-metal Catalysts for Polymerization
3. Lanthanide Complex Catalysts for Diene Elastomers
Shojiro KAITA
OM Chem-Tech. Co., Ltd./RIKEN, Cooperation Center, Saitama, Japan
Nippon Gomu Kyokaishi,(2004),77(12),427-431 General Review in Japanese

Recently, Nd-based catalyst systems have been developed for the polymerization of butadiene, and have already been widely used in industrial applications. However, the 1,4-cis selectivity and molecular weight distribution of the produced polybutadiene (BR) cannot be well controlled, since these catalyst systems are Ziegler-Natta based "multi-site" catalysts. On the other hand "single-site" catalyst system, lanthanide-metallocene/cocatalyst system, has attracted recent interest as the next generation catalyst system, which can induce ultimately specific 1,4-cis polymerization (>99.99%) and cis-specific living polymerization (sharp MWD). This article is a brief introduction of recent topics, including strategies aiming at these new elastomers based on tailor-made lanthanide-metallocene catalysts.

Lanthanide, Organometallic Catalyst, Metallocene Catalyst, Single-Site Catalyst, Diene Polymerization, Living Polymerization