Abstract: An ethylene polymerization process is disclosed. The polyethylene has a long-chain-branching index (LCBI) of 1 or greaster. The process uses a single-site catalyst that contains a boraaryl ligand. The catalyst is alkylated with triisobutyl aluminum.

Abstract: A high molecular weight, medium density polyethylene (HMW, MDPE) is disclosed. The polyethylene comprises from about 85 to about 98 wt % of recurring units of ethylene and about 2 to about 15 wt % of a C3-C10 &agr;-olefin. It has a density from about 0.92 to about 0.944 g/cc, a melt index MI2 from about 0.01 to about 0.5 dg/min, and a melt flow ratio MFR from about 50 to about 300. It has a multimodal molecular weight distribution comprising a high molecular weight component and a low molecular weight component. The low molecular weight component has an MI2 from about 50 to about 600 dg/min and a density from about 0.94 to about 0.97 g/cc. A process for making the medium density polyethylene is also disclosed. The process uses a Ziegler catalyst and applies multiple reaction zones.

Abstract: An ethylene polymerization process is disclosed. The polyethylene has a long-chain-branching index (LCBI) greater than about 1. The process uses a single-site catalyst that contains a boraaryl ligand. The catalyst is alkylated with triisobutyl aluminum.

Abstract: A high molecular weight, medium density polyethylene (HMW, MDPE) is disclosed. The polyethylene comprises from about 85 to about 98 wt % of recurring units of ethylene and about 2 to about 15 wt % of a C3-C10 &agr;-olefin. It has a density from about 0.92 to about 0.944 g/cc, a melt index MI2 from about 0.01 to about 0.5 dg/min, and a melt flow ratio MFR from about 50 to about 300. It has a multimodal molecular weight distribution comprising a high molecular weight component and a low molecular weight component. The low molecular weight component has an MI2 from about 50 to about 600 dg/min and a density from about 0.94 to about 0.97 g/cc. A process for making the medium density polyethylene is also disclosed. The process uses a Ziegler catalyst and applies multiple reaction zones.

Abstract: An ethylene polymerization process is disclosed. The process uses a single-site catalyst that contains a boraaryl ligand. It comprises supporting the catalyst, forming a slurry of the supported catalyst in an organic solvent, mixing the catalyst slurry with trialkyl aluminum compound, and polymerizing ethylene in the presence of the trialkyl aluminum-treated catalyst slurry. The process gives polyethylene having a controlled long-chain-branch index.

Abstract: A single-site olefin polymerization catalyst is described. The catalyst comprises an activator and an organometallic compound that includes a Group 3 to 10 transition or lanthanide metal, M, and a modified boraaryl ligand. We surprisingly found that the catalyst is more active in olefin polymerization compared to other catalysts containing non-modified boraaryl ligands. Most surprisingly, the supported catalyst gives polyolefins with a multimodal molecular weight distribution having separate components of distinct molecular weight.