Disclosed are catalyst compositions having an internal electron donor which includes a 3,6-di-substituted-1,2-phenylene aromatic diester. Ziegler-Natta catalyst compositions containing the present catalyst compositions exhibit very high hydrogen response, high activity, high selectivity and produce propylene-based olefins with high melt flow rate.

This invention relates to a process to polymerize olefins by contacting one or more olefins with a catalyst system comprising an organoaluminum treated layered silicate support, and a bridged metallocene compound and obtaining a polyolefin having a gvis of 0.90 or more and an MIR of 30 or less.

The present invention is directed to a synthetic polyisoprene which comprises isoprene repeat units comprising 1,4 isoprene repeat units and 3,4 isoprene repeat units. At least 5% of all isoprene repeat units of the synthetic polyisoprene are 3,4 isoprene repeat units and at least 96% of all 1,4 isoprene repeat units of the synthetic polyisoprene are cis 1,4 isoprene units. Moreover, the invention is directed to a method of synthesizing such a polyisoprene and a rubber composition comprising the synthetic polyisoprene.

The present disclosure provides a method for preparing a catalyst system comprising contacting in an aliphatic solvent at a temperature of from less than 0 C. to 60 C. at least one support material having absorbed water and at least one hydrocarbyl aluminum compound to form a supported alumoxane (catalyst precursor) and contacting the supported alumoxane with at least one catalyst compound having a Group 3 through Group 12 metal atom or lanthanide metal atom. The supported alumoxane may be heated prior to contact with the catalyst compound.

Polymerizable compositions comprising a redox initiator system is disclosed. The redox initiator system comprises a photolabile transition metal complex that photolyzes and initiates the redox cycle. Dental compositions comprising dental resins and the photolabile redox initiator system are also described.

A method for producing polyisoprene comprising: polymerizing isoprene by using an isoprene-containing composition containing isoprene and an oxygen-containing neutral compound, and a polymerization catalyst composition containing a rare earth element compound and an organometallic compound, wherein: a compounding amount of the organometallic compound is 0.6 to 3.0 parts by mass per 100 parts by mass of the isoprene-containing composition.

The present invention provides 1,4-cis polybutadiene having high linearity with an S/R value of 1 or greater at 100 C., and accordingly, is capable of reducing resistance properties, particularly rolling resistance, and greatly enhancing fuel efficiency properties when used in a rubber composition.

Catalyst compounds and catalyst systems including an asymmetric Salan ligands having a fluorenyl moiety are disclosed. Methods of preparing such catalyst compounds and catalyst systems, polymerization processes using such catalysts systems and olefin polymers prepared according to such processes using the catalysts systems are described.

This invention relates to a supported catalyst system and process for use thereof. In particular, the catalyst system includes a pyridyldiamido transition metal complex, an activator and a support material. The catalyst system may be used for preparing ultrahigh molecular weight polyolefins.

Catalyst component for the polymerization of olefins comprising Mg, Ti and an electron donor of formula (I) ##STR00001##
Where R.sub.1 and R.sub.2, independently, are selected from hydrogen and C.sub.1-C.sub.15 hydrocarbon groups, optionally contain an heteroatom selected from halogen, P, S, N, O and Si, which can be fused together to form one or more closed cycles and A is a bivalent bridging group.