Copolymerizations of ethylene and polar comonomers with bis(phenoxyketimine) group IV complexes: Effects of the central metal properties

With triisobutylaluminum as a protection reagent, copolymerizations of ethylene with 10-undecen-1-ol, 10-undecenoic acid, and 5-hexen-1-ol have been performed with bis[(3,5-di-Bu-t-C6H2-2-0)-PhC=N(2-F-C6H4)]ZrCl2 (a)/methylaluminoxane or bis[(3,5-di-Bu-t-C6H2-2-O)-PhC N(2-F-C6H4)]TiCl2 (b)/methylaluminoxane as the catalyst. Both catalysts exhibit high activities of copolymerization in the presence of polar groups. The properties of the copolymers are strongly affected by the central metal properties of the catalysts. In comparison with complex a, titanium complex b appears to be less sensitive to polar monomers and more favorable for the preparation of higher molecular weight functionalized polyethylenes containing higher contents of polar groups. Studies on the polymerization temperature indicate that the catalytic activities decrease greatly with both complex a and complex b. The comonorner contents incorporated into the copolymers are slightly dependent on the polymerization temperature in the case of complex a, whereas in the case of complex b, the effect of the polymerization temperature is more distinct: an increase in the pohmerization temperature can efficiently facilitate the incorporation of polar comonomers. (c) 2006 Wiley Periodicals, Inc.