Embodiments are directed to a catalyst system comprising metal ligand complexes and processes for polyolefin polymerization using the metal ligand complex having the following structure: Formula I. ##STR00001##

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.

The present disclosure relates to bis(aryl phenolate) Lewis base catalysts. Catalysts, catalyst systems, and processes of the present disclosure can provide high temperature ethylene polymerization, propylene polymerization, or copolymerization as the bis(aryl phenolate) Lewis base catalysts are stable at high polymerization temperatures and have good activity at the high polymerization temperatures. The stable catalysts with good activity can provide formation of polymers having high molecular weights and the ability to make an increased amount of polymer in a given reactor, as compared to conventional catalysts. Hence, the present disclosure demonstrates highly active catalysts capable of operating at high reactor temperatures while producing polymers with controlled molecular weights and or robust isotacticity.

Catalyst system, the catalyst system comprising (i) at least one metallocene complex of formula (I), (I) wherein Mt1 is Hf, X is a sigma-donor ligand, R.sup.1, R.sup.2, R.sup.3 are the same or different from each other and can be hydrogen or a saturated linear or branched C.sub.1-C.sub.10 alkyl, whereby the alkyl group can optionally contain up to 2 heteroatoms belonging to groups 14-16 of the periodic table, or R.sup.1 and R.sup.2 or R.sup.2 and R.sup.3 can form a ring having 4 to 6 C-atoms and 1 to 3 double bonds, R.sup.4 and R.sup.5 are the same or different from each other and can be saturated linear or branched C.sub.1-C.sub.10 alkyl, C.sub.5-C.sub.10 aryl, C.sub.6-C.sub.20 alkylaryl or C.sub.6-C.sub.20 arylalkyl groups, which can optionally contain up to 2 heteroatoms belonging to groups 14-16 of the periodic table, n can be 1 to 5, Ar is a C.sub.6-C.sub.20-aryl or -heteroarylgroup, which can be unsubstituted or substituted by 1 to 5 linear or branched C.sub.1-C.sub.10 alkyl group(s), and (ii) a boron containing cocatalyst. ##STR00001##

A method for increasing the melt strength of a polyolefin polymer composition is provided. The method includes mixing a first polyolefin composition derived from at least one olefin polymerization catalyst (a) and at least one olefin polymerization catalyst (b) with a second polyolefin composition derived from the at least one olefin polymerization catalyst (b) or from at least one olefin polymerization catalyst (c), and obtaining the polyolefin polymer composition.

The present disclosure provides bridged metallocene catalyst compounds comprising —Si—Si— bridges, catalyst systems comprising such compounds, and uses thereof. Catalyst compounds of the present disclosure can be hafnium-containing compounds having one or more cyclopentadiene ligand(s) substituted with one or more silyl neopentyl groups and linked with an Si—Si-containing bridge. In another class of embodiments, the present disclosure is directed to polymerization processes to produce polyolefin polymers from catalyst systems comprising one or more olefin polymerization catalysts, at least one activator, and an optional support.

The present disclosure relates to a process for synthesizing a multi- or dual-headed composition by using an alpha,omega-diene and an organometallic compound in the presence of a catalyst precursor. The present disclosure further relates to use of the compositions, as well as the process to make the same, in olefin polymerization.

The present disclosure relates to a process for synthesizing a multi- or dual-headed composition by using an alpha,omega-diene and an organometallic compound in the presence of a catalyst precursor. The present disclosure further relates to use of the compositions, as well as the process to make the same, in olefin polymerization.

The present disclosure relates to a capped, multi- or dual-headed chain composition comprising derivatives of a strained olefin. The present disclosure further relates to a process for synthesizing the capped, multi- or dual-headed composition by using an organometallic compound and a co-catalyst in the presence of a catalyst precursor and a strained olefin. The present disclosure further relates to use of the compositions, as well as the process to make the same, in olefin polymerization.

Polypropylene polymer compositions are disclosed that have excellent stiffness properties. The polypropylene polymer compositions are made by combining a first polypropylene polymer with a second polypropylene polymer. The combination of polymers has been found to produce a composition having high stiffness properties in addition to excellent toughness properties. In addition, the polymer composition has good flow properties for being molded into various products and articles. Of particular advantage, the different polypropylene polymers can be produced at relatively high catalyst activity, especially in comparison to high crystalline polymers made in the past.