Abstract: A method of performing a polymerization reaction in a gas phase polymerization reactor to produce a bimodal polymer while controlling activity of a bimodal polymerization catalyst composition in the reactor by controlling concentration of at least one induced condensing agent (‘ICA’) in the reactor is provided. In some embodiments, the ICA is isopentane (or another hydrocarbon compound) and the bimodal catalyst composition includes a Group 15 and metal containing catalyst compound (or other HMW catalyst for catalyzing polymerization of a high molecular weight fraction of the product), and a metallocene catalyst compound (or other LMW catalyst for catalyzing polymerization of a low molecular weight fraction of the product).

Abstract: Methods for gas phase olefin polymerization are provided. The method can include combining a spray dried catalyst system with a diluent to produce a catalyst slurry. The catalyst system can include a metallocene compound. Ethylene, a continuity additive, and the catalyst slurry can be introduced to a gas phase fluidized bed reactor. The reactor can be operated at conditions sufficient to produce a polyethylene. The spray dried catalyst system can have a catalyst productivity of at least 12,000 grams polyethylene per gram of the catalyst system.

Abstract: Polyethylene compositions having improved properties are provided. In one aspect, a polyethylene composition having a long chain branching index (g?avg) of 0.5 to 0.9; a Melt Flow Rate (MFR) of greater than (49.011×MI(?0.4304)), where MI is Melt Index; and a weight average molecular weight to number average molecular weight (Mw/Mn) of less than or equal to 4.6 is provided.

Abstract: A method for controlling a transition from an initial polymerization reaction to a target polymerization reaction in a manner that reduces significantly the amount of off-grade product having excessively low density produced during the transition, including steps of: during the transition, maintaining a first one of a concentration ratio and a feed ratio at an at least substantially constant value while implementing process changes in an effort to bring produced polymer into compliance with a target specification set and monitoring (without controlling) the other one of the concentration ratio and the feed ratio to generate first data; and during the transition, determining from the first data whether polymer having excessively low density is likely to be produced during the transition, and upon determining that polymer having excessively low density is likely to be produced during the transition, maintaining during the remaining portion of the transition the other ratio at a value that is at least substantia

Abstract: A process for polymerizing olefin(s) utilizing a cyclic bridged metallocene catalyst system to produce polymers with improved properties is provided. The catalyst system may include a cyclic bridged metallocene, LA(R?SiR?)LBZrQ2, activated by an activator, the activator comprising aluminoxane, a modified aluminoxane, or a mixture thereof, and supported by a support, where: LA and LB are independently an unsubstituted or a substituted cyclopentadienyl ligand bonded to Zr and defined by the formula (C5H4-dRd), where R is hydrogen, a hydrocarbyl substituent, a substituted hydrocarbyl substituent, or a heteroatom substituent, and where d is 0, 1, 2, 3 or 4; LA and LB are connected to one another with a cyclic silicon bridge, R?SiR?, where R? are independently hydrocarbyl or substituted hydrocarbyl substituents that are connected with each other to form a silacycle ring; and each Q is a labile hydrocarbyl or a substituted hydrocarbyl ligand.

Abstract: A method for controlling a transition from an initial polymerization reaction to a target polymerization reaction in a manner that reduces significantly the amount of off-grade product having excessively low density produced during the transition, including steps of: during the transition, maintaining a first one of a concentration ratio and a feed ratio at an at least substantially constant value while implementing process changes in an effort to bring produced polymer into compliance with a target specification set and monitoring (without controlling) the other one of the concentration ratio and the feed ratio to generate first data; and during the transition, determining from the first data whether polymer having excessively low density is likely to be produced during the transition, and upon determining that polymer having excessively low density is likely to be produced during the transition, maintaining during the remaining portion of the transition the other ratio at a value that is at least substantia

Abstract: Bimodal polyethylene compositions and methods for making the same are provided. In at least one specific embodiment, the bimodal polyethylene composition can include a high molecular weight component having a weight average molecular weight (Mw) of from about 400,000 to about 950,000. The bimodal polyethylene composition can also include a low molecular weight component having a weight average molecular weight (Mw) of from about 3,000 to about 100,000. The high molecular weight component can be present in an amount ranging from about 25 wt % to about 40 wt % of the bimodal polyethylene composition. The bimodal polyethylene composition can also have a percent die swell of less than about 80%.

Abstract: A nozzle for catalyst injection for olefin polymerization is provided. In one or more embodiments the nozzle includes a first conduit including a body, a tapered section, and an injection tip. The nozzle also includes a second conduit having an inner surface and an outer surface. The first conduit is disposed about the second conduit defining a first annulus therebetween. The nozzle further includes a support member at least partially disposed about the outer surface of the first conduit defining a second annulus therebetween. The support member has a converging outer surface at a first end thereof.

Abstract: The present invention is directed to the use of aluminum alkyl activators and co-catalysts to improve the performance of chromium-based catalysts. The aluminum alkyls allow for the variable control of polymer molecular weight, control of side branching while possessing desirable productivities, and may be applied to the catalyst directly or separately to the reactor. Adding the alkyl aluminum compound directly to the reactor (in-situ) eliminates induction times.

Abstract: Methods of controlling the flow index and/or molecular weight split of a polymer composition are disclosed. The method of producing a polymer composition in one embodiment comprises incorporating a high molecular weight polymer into a low molecular weight polymer to form the polymer composition in a single polymerization reactor in the presence of polymerizable monomers, a bimetallic catalyst composition and at least one control agent; wherein the control agent is added in an amount sufficient to control the level of incorporation of the high molecular weight polymer, the level of low molecular weight polymer, or both. Examples of control agents include alcohols, ethers, amines and oxygen.

Abstract: A process is provided for preparing a shape-shifted catalyst component comprising (1) contacting a dihydrocarbyloxide magnesium compound with carbon dioxide in the presence of a slurrying agent to form a slurry of a carboxylated dihydrocarbyloxide magnesium compound; (2) adding a filler to the slurry either before or after the carboxylation of step (1); (3) spray drying the slurry of step (2) to evaporate the slurrying agent and to produce solid particles of the carboxylated dihydrocarbyloxide magnesium compound incorporating the filler; and, optionally, (4) heating the solid particles to remove carbon dioxide to produce a shape-shifted dihydrocarbyloxide magnesium compound component. A catalyst system using the component and a polymerization process employing the catalyst system are also provided.

Abstract: A process is provided for preparing a shape-shifted catalyst component comprising (1) contacting a dihydrocarbyloxide magnesium compound with carbon dioxide in the presence of a slurrying agent to form a slurry of a carboxylated dihydrocarbyloxide magnesium compound; (2) adding a filler to the slurry either before or after the carboxylation of step (1); (3) spray drying the slurry of step (2) to evaporate the slurrying agent and to produce solid particles of the carboxylated dihydrocarbyloxide magnesium compound incorporating the filler; and, optionally, (4) heating the solid particles to remove carbon dioxide to produce a shape-shifted dihydrocarbyloxide magnesium compound component. A catalyst system using the component and a polymerization process employing the catalyst system are also provided.

Abstract: A method for passivating internal surfaces of a reactor system during start-up and shutdown of an alpha olefin polymerization or copolymerization reaction by adding a passivation agent such as a dialkyl zinc compound, an alcohol, or an epoxide, to the reactor prior to exposing the internal reactor surfaces to air or moisture before reaction initiation and/or after reaction ceases.

Abstract: A process comprising contacting a mixture comprising ethylene, propylene, and, optionally, a diene, in the gas phase, under polymerization conditions, with a catalyst system comprising:(a) a catalyst precursor, in independent or prepolymer form, consisting of vanadium (acetylacetonate).sub.3 ;(b) optionally, a support for said precursor;(c) a cocatalyst consisting essentially of (i) an alkylaluminum halide having the formula AlR.sub.(3-a) X.sub.a wherein each R is independently alkyl having 1 to 14 carbon atoms; each X is independently chlorine, bromine, or iodine; and a is 1 or 2, and (ii) optionally, a trialkylaluminum provided that the molar ratio of alkylaluminum halide to trialkylaluminum is at least about 1.

Abstract: Normally sparingly soluble magnesium alkoxide is solubilized in alkanol by the additional presence of certain acidic materials. The resulting solution is used to produce a mixture of substantially spherical particles, substantially free of fines, containing an adduct magnesium alkoxide. The particles are converted by conventional methods to a procatalyst precursor of an olefin polymerization catalyst of good activity and good selectivity to stereoregular polymer whenever appropriate, which catalyst produces polymer product of good morphology.