Highly active copolymerization of ethylene with 10-undecen-1-ol using phenoxy-based zirconium/methylaluminoxane catalysts

Activated with methylaluminoxane (MAO), phenoxy-based zirconium complexes bis[(3-^tBu-C₆H₃-2-O)-CH=NC₆H ₅]ZrCl₂, bis[(3,5-di-^tBu-C₆H ₂-2-O)-PhC=NC₆H₅] ZrCl₂, and bis[(3,5-di-^tBu-C₆H₂-2-O)-PhC=N(2-F-C ₆H₄)]ZrCl₂ for the first time have been used for the copolymerization of ethylene with 10-undecen-1-ol. In comparison with the conventional metallocene, the phenoxy-based zirconium complexes exhibit much higher catalytic activities [>107 g of polymer (mol of catalyst) ^-1 h^-1]. The incorporation of 10-undecen-1-ol into the copolymers and the properties of the copolymers are strongly affected by the catalyst structure. Among the three catalysts, complex c is the most favorable for preparing higher molecular weight functionalized polyethylene containing a higher content of hydroxyl groups. Studies on the polymerization conditions indicate that the incorporated commoner content in the copolymers mainly depends on the comonomer concentration in the feed. The catalytic activity is slightly affected by the Al_(MAO)/Zr molar ratio but decreases greatly with an increase in the polymerization temperature.