Recent Data on the Number of Active Centers and Propagation Rate Constants in Olefin Polymerization with Supported ZN Catalysts
Stereo specific Polymerization and Stereoregular Polymers : European Polymer Conference
08-12 Jun 2003
||Stereospecific Polymerization and Stereoregular Polymers
, E-ISSN: 1521-3900
||Active centers, Polyethylene, Polypropylene, Stereospecificity, Ziegler-Natta polymerization
Boreskov Institute of Catalysis, Novosibirsk, 630090, Russia
Data on the number of active centers (Cp) and propagation rate constants (Kp) have been obtained by means of polymerization quenching with 14CO of propylene and ethylene polymerization with supported titanium-magnesium catalysts (TMC) with different composition. In the case of propylene polymerization the Cp and Kp values have been measured separately for isospecific, aspecific and low stereospecific centers. Effects of MgCl2 support, internal and external donors are discussed on the basis of data obtained.
Data on the strong effect of diffusion limitation at ethylene polymerization with number of TMC have been obtained and a set of methods have been used to exclude this effect. Data on Cp and Kp values at ethylene polymerization with low stereospecific and highly stereospecific catalysts are presented.