Ethylene-based polymers having a density of 0.952 to 0.968 g/cm3. a ratio of HLMI/MI from 185 to 550. an IB parameter from 1.46 to 1.80, a tan δ at 0.1 sec.sup.-1 from 1.05 to 1.75 degrees, and a slope of a plot of viscosity versus shear rate at 100 sec.sup.-1 from 0.18 to 0.28 are described, with low melt flow versions having a HLMI from 10 to 30 g/10 min and a Mw from 250,000 to 450,000 g/mol, and high melt flow versions having a HLMI from 30 to 55 g/10 min and a Mw from 200,000 to 300,000 g/mol. These polymers have the processability of chromium-based resins, but with improved stress crack resistance and topload strength for bottles and other blow molded products.

A nucleating agent-free and LLDPE-free polyolefin composition for making films with enhanced barrier properties against water vapor and oxygen gas. Related aspects include formulations, manufactured articles, films, and methods.

A nucleating agent-free and LLDPE-free polyolefin composition for making films with enhanced barrier properties against water vapor and oxygen gas. Related aspects include formulations, manufactured articles, films, and methods.

Polyethylene compositions described herein have a density from about 0.900 g/cm.sup.3 to about 0.950 g/cm.sup.3, a MI (I.sub.2, 190° C., 2.16 kg) from about 0.1 g/10 min to about 10 g/10 min, an MIR (I.sub.21/I.sub.2) from about 25 to about 80, an M.sub.z greater than or equal to about 150,000 g/mol, and either an M.sub.z/M.sub.n ratio greater than or equal to about 8.0, an M.sub.z/M.sub.w ratio greater than or equal to about 2.4, or an (I.sub.2*M.sub.z/M.sub.n) from about 3 to about 100. The polyethylene compositions are useful in wire and cable, tape, and filament applications, and could be produced using a gas phase or slurry phase, preferably gas phase, polymerization process.

Polyethylene compositions described herein have a density from about 0.900 g/cm.sup.3 to about 0.950 g/cm.sup.3, a MI (I.sub.2, 190° C., 2.16 kg) from about 0.1 g/10 min to about 10 g/10 min, an MIR (I.sub.21/I.sub.2) from about 25 to about 80, an M.sub.z greater than or equal to about 150,000 g/mol, and either an M.sub.z/M.sub.n ratio greater than or equal to about 8.0, an M.sub.z/M.sub.w ratio greater than or equal to about 2.4, or an (I.sub.2*M.sub.z/M.sub.n) from about 3 to about 100. The polyethylene compositions are useful in wire and cable, tape, and filament applications, and could be produced using a gas phase or slurry phase, preferably gas phase, polymerization process.

Catalyst systems and methods for making and using the same. A method of methylating a catalyst composition while substantially normalizing the entiomeric distribution is provided. The method includes slurrying the organometallic compound in dimethoxyethane (DME), and adding a solution of RMgBr in DME, wherein R is a methyl group or a benzyl group, and wherein the RMgBr is greater than about 2.3 equivalents relative to the organometallic compound. After the addition of the RMgBr, the slurry is mixed for at least about four hours. An alkylated organometallic is isolated, wherein the methylated species has a meso/rac ratio that is between about 0.9 and about 1.2.

Catalyst systems and methods for making and using the same. A method of methylating a catalyst composition while substantially normalizing the entiomeric distribution is provided. The method includes slurrying the organometallic compound in dimethoxyethane (DME), and adding a solution of RMgBr in DME, wherein R is a methyl group or a benzyl group, and wherein the RMgBr is greater than about 2.3 equivalents relative to the organometallic compound. After the addition of the RMgBr, the slurry is mixed for at least about four hours. An alkylated organometallic is isolated, wherein the methylated species has a meso/rac ratio that is between about 0.9 and about 1.2.

A supported metallocene catalyst can include a silica-based carrier and an aluminum alkyl halide, a cocatalyst compound, and a metallocene compound supported in the silica-based carrier. The aluminum alkyl halide is supported at higher rate on the surface of the silica-based carrier than inside the pores, and the cocatalyst compound is supported at higher rate inside the pores of the silica-based carrier than on the surface of the silica-based carrier. Such a supported metallocene catalyst can be prepared by: (i) supporting an aluminum alkyl halide in a silica-based carrier; (ii) supporting a cocatalyst compound in the silica-based carrier in which the aluminum alkyl halide is supported; and (iii) supporting a metallocene compound in the carrier in which the aluminum alkyl halide and the cocatalyst compound are supported. Such a supported metallocene catalyst can be used to polymerize polyolefins with excellent activity and polyolefin with a uniform powder morphology.

A supported metallocene catalyst can include a silica-based carrier and an aluminum alkyl halide, a cocatalyst compound, and a metallocene compound supported in the silica-based carrier. The aluminum alkyl halide is supported at higher rate on the surface of the silica-based carrier than inside the pores, and the cocatalyst compound is supported at higher rate inside the pores of the silica-based carrier than on the surface of the silica-based carrier. Such a supported metallocene catalyst can be prepared by: (i) supporting an aluminum alkyl halide in a silica-based carrier; (ii) supporting a cocatalyst compound in the silica-based carrier in which the aluminum alkyl halide is supported; and (iii) supporting a metallocene compound in the carrier in which the aluminum alkyl halide and the cocatalyst compound are supported. Such a supported metallocene catalyst can be used to polymerize polyolefins with excellent activity and polyolefin with a uniform powder morphology.

The alkylation of transition metal coordination catalyst complexes (such as metallocenes and/or post-metallocenes) in non-polar solvents with high conversion to the dialkylated transition metal coordination catalyst complex may be accomplished by reacting (a) a transition metal coordination catalyst complex comprising a transition metal linked to at least one an anionic donor ligand and at least one leaving group having a non-carbon atom directly linked to the transition metal, (b) an aluminum alkyl, and (c) a fluoride salt at 0° C. to 85° C. in a non-polar solvent to yield an alkylated transition metal coordination catalyst complex.