Phenoxide Modified Half-Titanocenes–Supported MAO Catalyst Systems for Ethylene Slurry Polymerization with Controlled Morphology

Transition metal catalyzed olefin coordination polymerization is the key technology for production of polyolefin (high-density polyethylene, isotactic polypropylene etc.); the slurry polymerization process has been employed in terms of better mass transport and temperature controls. In this study, ethylene slurry polymerizations by Cp*TiCl2(O-2,6-iPr2-4-R-C6H2) [Cp* = C5Me5; R = H (1), SiEt3 (2)] were studied in the presence of poly(methylaluminoxane) support cocatalyst (sMAO). These polymerizations conducted at 25–70 ºC gave spherical polyethylene particles without formation of fluffy PE materials irrespective of the amount of catalyst and/or sMAO loadings, strongly suggest that sMAO plays a role as a template for the particle growing with control of the shape during the polymerization event (called replica effect). The activities at 70 ºC by 2 showed higher than 1, and the yields in the polymerization by 1–sMAO catalyst system increased over time course.