Macromolecular Rapid Communications, Vol.23, No.18, 1118-1123, 2002
Propylene polymerization with bis(phenoxy-imine) group-4 catalysts using (Bu3Al)-Bu-i/Ph3CB(C6F5)(4) as a cocatalyst
The catalytic behaviour of three bis(phenoxy) group-4 transition-metal complexes (M=Ti, Zr, Hf), with (Bu3AlCB)-Bu-i(C6F5)(4) cocatalyst systems towards propylene polymerization was investigated under atmospheric pressure at 25degreesC. The Ti complex produced ultrahigh-molecular-weightatactic poly(propylene), whereas Zr and Hf complexes formed high-molecular-weight isotactic poly(propylene)s via a site-control mechanism. The isotactic poly(propylene) obtained with the Hf complex displayed a high melting temperature of 123.8degreesC.