Abstract: In an ongoing process for the production of polypropylene polymer, propylene monomer is contacted with a polypropylene polymerization catalyst under polymerization conditions in the presence of molecular hydrogen to control polymer molecular weight and polymer properties such as melt flow. Production of polymer having increased or decreased melt flow is achieved by contacting at least a portion of the recycle gas with a metal hydride or metal hydride precursor under conditions whereby the hydrogen concentration of the recycle gas and thus the polymerization reactor is increased or decreased, respectively. The increase or decrease in hydrogen concentration in the polymerization reactor results in production of polypropylene polymer product of higher or lower melt flow.

Abstract: A process for polymerizing or copolymerizing a member of the group consisting of an alpha olefin or mixtures thereof, consisting of the steps of:polymerizing an alpha olefin in a polymerization reactor using a polymerization catalyst, a cocatalyst, and an amount of hydrogen adjusted for molecular weight control as measured by melt flow;rapidly changing the melt flow of the polymerized alpha olefin from high to low melt flow by reacting a portion of the unreacted hydrogen in the reactor with a quantity of the alpha olefin present therein by interaction with a hydrogenation catalyst; andremoving the hydrogenation catalyst from the reactor through continuous exchange of the reactor contents.

Abstract: Olefin polymerization catalyst components having improved activity and morphological properties are disclosed and claimed. In particular, the components are prepared by reacting a carbonized magnesium alkoxide or aryloxide component with a halogenated tetravalent titanium component, a halohydrocarbon component and an electron donor.

Abstract: Olefin polymerization catalyst components having improved activity and morphological properties are disclosed and claimed. In particular, the components are prepared by reacting a carbonized magnesium alkoxide or aryloxide component with a halogenated tetravalent titanium component, a halohydrocarbon component and an electron donor.

Abstract: A process for the preparation of ethylene-propylene impact copolymers at improved catalyst productivity rates involving the formation of a propylene prepolymer by polymerization of propylene in liquid phase in the presence of a catalyst system containing titanium halide supported on magnesium halide and aluminum alkyl complexed with an electron donor. Ethylene and propylene are block polymerized onto the prepolymer in a vapor phase reaction zone in the presence of a second catalyst system comprising a solution of a C.sub.5 -C.sub.9 polyalpha-monoolefin/catalyst/diluent.