Abstract: Embodiments of the present disclosure are directed towards methods for controlling a polymerization reaction including determining an instantaneous density model for a gas-phase polymerization, and utilizing the instantaneous density model to monitor the polymerization reaction to determine if a threshold instantaneous density is reached.

Abstract: Methods and systems for olefin polymerization are provided. The method for olefin polymerization can include flowing a catalyst through an injection nozzle and into a fluidized bed disposed within a reactor. The method can also include flowing a feed comprising one or more monomers, one or more inert fluids, or a combination thereof through the injection nozzle and into the fluidized bed. The feed can be at a temperature greater than ambient temperature. The method can also include contacting one or more olefins with the catalyst within the fluidized bed at conditions sufficient to produce a polyolefin.

Abstract: A method comprising synthesizing a cyclic organic compound via reaction of an unsubstituted or substituted cycloheptene with an unsubstituted or substituted acrylic acid in the presence of phosphoric and/or sulfonic acid reagent to make the cyclic organic compound. Also, a method of synthesizing a ligand for a transition metal, and a related substituted ligand-metal complex and catalyst, from the unsubstituted or substituted cycloheptene and unsubstituted or substituted acrylic acid. Also, the cyclic organic compound, ligand, and substituted ligand-metal complex and catalyst synthesized thereby. Also a method of polymerizing an olefin with the catalyst to give a polyolefin, and the polyolefin made thereby.

Abstract: Embodiments of the present disclosure are directed towards methods of adjusting melt index and/or density utilizing a metallocene complex represented by Formula (I): wherein each n-Pr is n-propyl, and each X is independently CH3, CI, Br, or F.

Abstract: An activated, titanium-based, spray-dried Ziegler-Natta catalyst system containing a titanium-based Ziegler-Natta catalyst, a carrier material, and an activator mixture comprising an effective amount of an activator mixture comprising triethylaluminum and diethylaluminum chloride for producing a substantially uniform comonomer composition distribution. Also, polyolefins; methods of making and using same; and articles containing same.

Abstract: A method including a) polymerizing at least one monomer in a gas phase reactor in the presence of a supported multimodal catalyst system to form a multimodal polyethylene product having a reactor split equal to respective weight fractions of resin components in the polyethylene product; b) applying a predetermined formula for a product parameter of the multimodal polyethylene product; c) obtaining incorporation data and production rate data from the reaction based upon the predetermined formula; d) determining an actual hydrogen leading indicator; e) comparing the actual hydrogen leading indicator to a target value for a hydrogen leading indicator to determine a deviation of the actual hydrogen leading indicator from the target value; and f) adjusting an amount of a catalyst precursor being fed to the gas phase reactor to control reactor split and a product parameter.

Abstract: A method comprising synthesizing a cyclic organic compound via reaction of an unsubstituted or substituted cyclopentene with an unsubstituted or substituted acrylic acid in the presence of phosphoric and/or sulfonic acid reagent to make the cyclic organic compound. Also, a method of synthesizing a ligand for a transition metal, and a related substituted ligand-metal complex and catalyst, from the unsubstituted or substituted cyclopentene and unsubstituted or substituted acrylic acid. Also, the cyclic organic compound, ligand, and substituted ligand-metal complex and catalyst synthesized thereby. Also a method of polymerizing an olefin with the catalyst to give a polyolefin, and the polyolefin made thereby.

Abstract: A polyethylene blend comprising a uniform dispersion of constituents (A) and (B): (A) a Ziegler-Natta catalyst-made linear low density polyethylene and (B) a metallocene catalyst-made linear low density polyethylene, a composition comprising the polyethylene blend and at least one additive, methods of making and using same, and manufactured articles and films comprising or made from same.

Abstract: A system and method for charging a chromium-based catalyst to a mix vessel; introducing a reducing agent through an entrance arrangement into the mix vessel, and agitating a mixture of the chromium-based catalyst, the reducing agent, and a solvent in the mix vessel to promote contact of the reducing agent with the chromium-based catalyst to give a reduced chromium-based catalyst.

Abstract: Novel polyethylene copolymers having a relatively high comonomer partitioning tendency are disclosed as are methods for their preparation. The comonomer partitioning tendency is the tendency for a copolymer to have comonomer in the higher molecular weight chains. Novel metrics for describing the comonomer partitioning tendency are also disclosed.

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: 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: 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: 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: 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: 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: 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.