Abstract: Disclosed herein are methods of controlling polymer properties in polymerization processes that use a chromium-based catalyst. An embodiment discloses a method of producing a polyolefin comprising: contacting a reaction mixture and a reduced chromium oxide catalyst in a gas-phase reactor to produce the polyolefin, wherein the reaction mixture comprises a monomer and a co-monomer; and changing a reaction temperature in the gas-phase reactor by about 1° C. or more whereby a gas molar ratio of the co-monomer to the monomer is changed by about 2% or more and a co-monomer content of the polyolefin at substantially constant density is changed by about 2% or more. Additional methods and compositions are also provided.

Abstract: Methods of making spray-dried Ziegler-Natta (pro)catalyst systems containing titanium Ziegler-Natta (pro)catalysts, a hydrophobic silica carrier material, and tetrahydrofuran. The spray-dried Ziegler-Natta (pro)catalyst systems made by the method. Methods of polymerizing olefin (co)monomer(s) with the spray-dried Ziegler-Natta catalyst system to make polyolefin polymers, and the polyolefin polymers made thereby.

Abstract: 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.

Abstract: A high density, high polydispersity polyethylene having improved properties, and a process of producing same.

Abstract: A bimodal polyethylene composition made with a bimodal catalyst system, wherein the bimodal polyethylene composition has from greater than 0 to 14 weight percent of polyethylene polymers having a weight-average molecular weight of from greater than 0 to 10,000 grams per mol, products made therefrom, methods of making and using same, and articles containing same.

Abstract: Embodiments of the present disclosure are directed towards metal complexes that can be utilized to form polymers. As an example, the present disclosure provides a metal complex of Formula I: wherein each Me represents methyl.

Abstract: The present disclosure provides a method of determining a relative decrease in catalytic efficacy of a catalyst in a test sample of a catalyst solution with unknown catalytic activity. The method includes (a) mixing the test sample with a test solvent to form a test mixture and (b) measuring the increase in the temperature of the test mixture at predetermined time intervals immediately after forming the test mixture. A predetermined feature is used to determine both a test value in the increase in temperature measured in (b) and a control value in a known increase in temperature of a control mixture of the test solvent with a control sample of a control catalyst solution. The relative decrease in catalytic efficacy of the catalyst in the test sample having the unknown catalytic activity is then determined from: Relative Decrease in Catalytic Efficacy=Control Value?Test Value/Control Value.

Abstract: The present disclosure provides a method for improving the activity of Ziegler-Natta (ZN) catalysts. The method includes forming a modified precursor composition of a ZN catalyst by providing a precursor composition of the ZN catalyst for treatment with an aluminum alkyl compound in a liquid organic solvent. The precursor composition of the ZN catalyst includes at least one titanium compound. The at least one titanium compound in the precursor composition is treated with the aluminum alkyl compound in the liquid organic solvent, where the aluminum alkyl compound converts the at least one titanium compound in the precursor composition into a modified state of the ZN catalyst. At least a portion of the aluminum alkyl compound not consumed in converting the at least one titanium compound in the precursor composition into the modified state of the ZN catalyst and reaction by-product compounds in the liquid organic solvent are removed to form the modified precursor composition of the ZN catalyst.

Abstract: Embodiments of the present disclosure are directed towards methods for rating polymerization processes based upon a first cracking index value and a second cracking index value.

Abstract: An ethylene/alpha-olefin copolymer that can be synthesized in a fluidized-bed, gas phase polymerization reactor and made into a blown film. The ethylene/alpha-olefin copolymer is characterized by a bubble stability-effective combination of properties comprising density, melt flow ratio (“I21/I5”), and melt storage modulus G? (G?=3,000 Pa). The synthesis in the FB-GPP reactor is characterized by a property-imparting-effective combination of operating conditions comprising reactor bed temperature and H2/C2 gas molar ratio. An embodiment of the blown film consisting of the ethylene/alpha-olefin copolymer is characterized by enhanced bubble stability. A method of making the ethylene/alpha-olefin copolymer. A film comprising the ethylene/alpha-olefin copolymer. A method of making the film. A manufactured article comprising the film.

Abstract: A method of selectively transitioning a polymerization process making an ethylene/alpha-olefin copolymer in such a way that melt elasticity of the copolymer is substantially changed without changing comonomer and without substantially changing density of the copolymer. A method of compensating a reactor temperature-induced change in melt elasticity with an inverse change in H2/C2 gas molar ratio. Also, use of process control variable(s) to selectively change the melt elasticity.

Abstract: Provided are various bimodal polyethylene, including but not limited to a bimodal polyethylene for a pipe having a density of from 0.9340 to 0.9470 gram/cubic centimeters (g/ccm), a melt index (12) of from 0.1 to 0.7 gram/10 minute, a melt flow ratio (121/12) of from 20 to 90. The bimodal polyethylene includes a high molecular weight polyethylene component and a low molecular weight polyethylene component which are a reaction product of a polymerization process performed in a single reactor and that employs a bimodal polymerization catalyst system. The bimodal polymerization catalyst system includes a bimodal catalyst system of bis(2-pentamethylphenylamido)ethyl)amine Zirconium dibenzyl and either (tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)Zirconium dichloride or (tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconium dimethyl in a 3.0:1 molar ratio; and a trim catalyst of (tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)Zirconium dichloridedimethyl in heptane added to adjust melt.

Abstract: A bimodal linear polyethylene composition, products made therefrom, methods of making and using same, and articles containing same.

Abstract: 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.

Abstract: An ethylene/1-hexene copolymer has a density from 0.9541 to 0.9600 gram per cubic centimeter (g/cm3), a molecular mass dispersity (DM=Mw/Mn) from greater than 2.0 to 3.5; and a Z-average molecular weight (Mz) from 120,000 to 240,000 grams per mole (g/mol). Methods of making and using same. Articles containing same.

Abstract: Method of preparing a molecular catalyst from a mixture comprising a (C5-C7)alkane, a spray-dried alkylaluminoxane, and a molecular procatalyst. Molecular catalysts prepared by the method may be screened.

Abstract: Polymerization process control methods for making polyethylene are provided. The process control methods include performing a polymerization reaction in a polymerization reactor to produce the polyethylene, where ethylene, and optionally one or more comonomers, in the polymerization reaction is catalyzed by an electron donor-free Ziegler-Natta catalyst and an alkyl aluminum co-catalyst. A melt flow ratio (I21/I2) of the polyethylene removed from the polymerization reactor is measured and an amount of long chain branching (LCB) of the polyethylene from the polymerization reactor is controlled by adjusting a weight concentration of the alkyl aluminum co-catalyst present in the polymerization reactor.

Abstract: A system and method of producing polyethylene, including: polymerizing ethylene in presence of a catalyst system in a reactor to form polyethylene, wherein the catalyst system includes a first catalyst and a second catalyst; and adjusting reactor conditions and an amount of the second catalyst fed to the reactor to control melt index (MI), density, and melt flow ratio (MFR) of the polyethylene.

Abstract: Methods for olefin polymerization are described. The methods include a) forming a first polyolefin under a first set of polymerization conditions in the presence of a first catalyst composition and a first concentration of at least a first continuity additive composition, the first polyolefin composition having a target density, ?1, and a target Flow Index, FI1; and b) forming a second polyolefin composition under a second set of polymerization conditions in the presence of a second catalyst composition and a second concentration of a second continuity additive composition, the second polyolefin composition having a target density, ?2, and a target Flow Index, FI2; wherein the process is essentially free of providing a polymerization neutralizing composition between steps a) and b).

Abstract: Embodiments of the present disclosure directed towards bimodal polymerization catalysts. As an example, the present disclosure provides a bimodal polymerization catalyst system including a non-metallocene olefin polymerization catalyst and a zirconocene catalyst of Formula I: (Formula I) where each of R1, R2, and R4 are independently a C1 to C20 alkyl, aryl or aralkyl group or a hydrogen, where R3 is a C1 to C20 alkyl, aryl or aralkyl group, and where each X is independently a halide, C1 to C20 alkyl, aralkyl group or hydrogen.