||Recent Developments of Organotransition-metal Catalysts for Polymerization
1. The Synthesis of Olefin Elastomers
OM Chem-Tech. Co., Ltd./RIKEN, Cooperation Center Saitama, Japan
Nippon Gomu Kyokaishi,(2004),77(9),312-316 General Review in Japanese
Design and fine-tuning of olefin-polymerization systems with organometallic
catalysts have attracted recent interest. These catalysts, unlike the classical
Ziegler-Natta systems, generate "single" active sites that enable more precise
control of molecular weight, molecular weight distribution, and in particular,
stereo-regularity of the resulting polymer. Such systems, initially devoted to
polymerization of ethylene and propylene targeting engineering plastics, are
recently being applied to the synthesis of novel elastomers.
This article is a brief introduction of such topics, including synthesis of
EPM-equivalent polymers by homo-polymerization of propylene, and isotactic-atactic
or isotactic-hemiisotactic stereo-block polymerization of propylene.
Strategies aiming at these new elastomers based on tailor-made organometallic
catalysts are also described.
Organometallic Catalyst, Metallocene Catalyst, Single-Site Catalyst, Olefin Polymerization, Stereoblock PP, Thermoplastic Elastomer