Abstract: A catalyst system useful in polymerizing olefins comprising a solid, hydrocarbon-insoluble catalyst component containing magnesium, titanium and halogen and an internal or external electron donor comprising a substituted hydrocarbyl four to eight-membered cycloalkane dicarboxylate wherein the substituents are positioned on the cycloalkane to place the dicarboxylate groups into adjacent conformational positions and wherein the substitutes contain 1 to 20 carbon atoms and may be joined to the cycloalkane structure to form a bicyclo structure.

Abstract: A catalyst system useful in polymerizing olefins comprising a solid, hydrocarbon-insoluble catalyst component containing magnesium, titanium and halogen and an internal or external electron donor comprising a substituted hydrocarbyl four to eight-membered cycloalkane dicarboxylate wherein the substituents are positioned on the cycloalkane to place the dicarboxylate groups into adjacent conformational positions and wherein the substitutes contain 1 to 20 carbon atoms and may be joined to the cycloalkane structure to form a bicyclo structure.

Abstract: An olefin polymerization process comprises gas-phase polymerization of at least one olefin monomer in more than one polymerization zones using a high activity Ziegler-Natta catalyst system comprising a solid, magnesium-supported, titanium-containing component and an aluminum alkyl component comprising introducing the titanium-containing component and an aluminum alkyl component into the first polymerization zone and then introducing additional aluminum alkyl component into a subsequent polymerization zone without added titanium-containing component.

Abstract: An olefin polymerization process comprises gas-phase polymerization of at least one olefin monomer in a reactor using a Ziegler-Natta or metallocene catalyst system in the presence of at least one suitable radical-generating compound in an amount sufficient for polymer modification and subsequent stabilization of such compound and generated radicals before post-reactor heat processing.

Abstract: A catalyst system useful in polymerizing olefins comprising a solid, hydrocarbon-insoluble catalyst component containing magnesium, titanium and halogen and an internal or external electron donor comprising a substituted hydrocarbyl four to eight-membered cycloalkane dicarboxylate wherein the substituents are positioned on the cycloalkane to place the dicarboxylate groups into adjacent conformational positions and wherein the substitutes contain 1 to 20 carbon atoms and may be joined to the cycloalkane structure to form a bicyclo structure.

Abstract: A metallocene catalyst may be temporarily and reversibly passivated by contact with an effective amount of an unsaturated hydrocarbon passivating compound.

Abstract: An olefin polymerization process comprises gas-phase polymerization of at least one olefin monomer in a reactor using a Ziegler-Natta or metallocene catalyst system in the presence of at least one suitable radical-generating compound in an amount sufficient for polymer modification and subsequent stabilization of such compound and generated radicals before post-reactor heat processing.

Abstract: A gas-phase olefin polymerization process in a plug flow reactor uses a catalyst system containing a magnesium halide supported titanium-containing component, an organoaluminum component, and at least one external electron donor component; in the process a first external donor component is added to the reactor at an injection point axially near an injection point for the supported transition metal containing component, and at least a second external donor component is added to the reactor axially downstream from the injection point for the first external donor component.

Abstract: A metallocene catalyst may be temporarily and reversibly passivated by contact with an effective amount of an unsaturated hydrocarbon passivating compound.

Abstract: A metallocene catalyst may be temporarily and reversibly passivated by contact with an effective amount of an unsaturated hydrocarbon passivating compound.

Abstract: A gas-phase olefin polymerization process in a plug flow reactor uses a catalyst system containing a magnesium halide supported titanium-containing component, an organoaluminum component, and at least one external electron donor component; in the process a first external donor component is added to the reactor at an injection point axially near an injection point for the supported transition metal containing component, and at least a second external donor component is added to the reactor axially downstream from the injection point for the first external donor component.

Abstract: A metallocene catalyst may be temporarily and reversibly passivated by contact with an effective amount of an unsaturated hydrocarbon passivating compound.

Abstract: A process to produce high melt flow propylene polymer comprises polymerizing propylene in the presence of a titanium-containing, magnesium-containing, high activity catalyst and an aluminum alkyl cocatalyst in a gas phase system which uses condensed liquid to control temperature wherein the external catalyst modifier is a tetraalkylorthosilicate, preferably tetraethylorthosilicate, at process conditions of temperature, hydrogen concentration, and Si/Mg, Al/Mg and Al/Si atomic ratios, to produce a high melt flow propylene polymer at high yield.

Abstract: A multistage method for making a homopolymer or copolymer of an alpha-olefin having increased stiffness and broadened molecular weight distribution.