Combination of nickel and titanium complexes containing nitrogen ligands as catalyst for polyethylene reactor blending

Abstract

Ethylene was polymerized using a combination of Ni(diimine)Cl2 (1) (diimine = 1,4-bis(2,6-diisopropylphenyl)-acenaphthenediimine) and {TpMs*}TiCl3 (2) (TpMs* = hydridobis(3-mesitylpyrazol-1-yl)(5-mesitylpyrazol-1-yl)) compounds in the presence of methylaluminoxane (MAO) at 30°C. The productivity reaches a maximum at XNi = 0.75 (1 400 kg of PE/mol[M] · h), and the produced polyethylene (PE) showed maximal melt flow index (0.13 g/10 min) and minimal intrinsic viscosity (2.24 dL/g) compared to polyethylenes obtained with different values of nickel loading fractions (XNi). Productivity, intrinsic viscosity data, as well as melt flow index measurements markedly depend upon the content of the late transition metal, thus suggesting a synergic effect between nickel and titanium catalysts. © Wiley-VCH Verlag GmbH, 2000.