A process for producing polyethylene polymers including contacting ethylene and at least one C.sub.3 to C.sub.8 alpha-olefin comonomer with a polymerization catalyst on a particulate support in a fluidized bed polymerization reactor under conditions effective to polymerize at least part of the ethylene and comonomer and produce the polyethylene polymers, wherein the support has a d.sub.10 particle size as measured by laser diffraction of at least 18 microns, is provided.

Compositions are provided which include blends of (A) branched and/or bimodal ethylene copolymers and (B) linear ethylene copolymers. The branched and/or bimodal ethylene copolymers may be produced using a dual metallocene catalyst system comprising two different metallocene catalysts: one capable of producing high Mooney-viscosity polymers and one suitable for producing polymers having at least a portion of vinyl terminations. The linear ethylene copolymers may be produced using a metallocene catalyst capable of producing high Mooney-viscosity polymers, which may be the same as such catalyst of the dual metallocene catalyst system. Processes for making such blends, including parallel and/or series polymerization processes, are also provided. The blends may have excellent cure properties suitable in curable rubber compound applications.

Provided herein are methods and systems for at least partially deactivating at least one component of a reactor effluent from gas phase polyolefin polymerization processes utilizing at least one glycol.

A main purpose of the present invention is to provide a multi-block copolymer composition having good elasticity and excellent stress relaxation properties, as well as small tension set. The present invention achieves the purpose by providing a multi-block copolymer composition obtained by a modification treatment, the composition including a block copolymer B formed by introducing a functional group capable of forming a non-covalent bond to a block copolymer A; wherein the block copolymer A includes a block copolymer A1 having a specific primary structure and a block copolymer A2 having a specific primary structure, and the mass ratio (A1/A2) of the block copolymer A1 and the block copolymer A2 is 100/0 to 50/50.

The invention provides a polyolefin composition comprising: (i) 55 to 95 wt % of a propylene butene random copolymer having an MFR.sub.2 of 1.0 to 20.0 g/10 min, a butene content of 1.5 to 8.0 wt % and prepared using a single site catalyst; and (ii) to 45 wt % of an ethylene based plastomer having a density of 860 to 905 kg/m.sup.3, an MFR.sub.2 of 0.3 to 30 g/10 min and prepared using a single site catalyst.

Catalyst systems and methods for making and using the same are described. A method includes selecting a catalyst blend using a blend polydispersity index (bPDI) map. The polydispersity map is generated by generating a number of polymers for at least two catalysts. Each polymer is generated at a different hydrogen to ethylene ratio. At least one catalyst generates a higher molecular weight polymer and another catalyst generates a lower molecular weight polymer. A molecular weight for each polymer is measured. The relationship between the molecular weight of the polymers generated by each of the catalysts and the ratio of hydrogen to ethylene is determined. A family of bPDI curves for polymers that would be made using a number of ratios of a blend of the at least two catalysts for each of a number of ratios of hydrogen to ethylene. A ratio for the catalyst blend of the catalysts that generates a polymer having a bPDI that matches a polymer fabrication process is selected, and the product specific polyolefin is made using the catalyst blend.

The invention relates to a process for the production of a foam having low organic compounds emissions, to polypropylene foamed products obtainable by the process, and to a process for the manufacture of low organic compounds emission articles comprising a foam for use in cars and food packaging. The process comprises the steps of: a) providing a foam comprising a propylene composition comprising a high melt strength propylene (HMS-PP) homopolymer or copolymer or combinations thereof, said HMS-PP foam having a melt strength of at least 25 cN at a maximum speed of at least 200 mm/s and a melting temperature of at least 135 C. and b) subjecting the HMS-PP foam to a thermal treatment at a temperature Tt which is preferably between 5 and 15 C. below the melting temperature Tm of the HMS-PP for a duration between preferably 1 and 10 minutes.

Methods for simultaneously determining the concentrations of transition metal compounds in solutions containing two or more transition metal compounds are described. Polymerization reactor systems providing real-time monitoring and control of the concentrations of the transition metal components of a multicomponent catalyst system are disclosed, as well as methods for operating such polymerization reactor systems.

Catalyst systems and methods for making and using the same. A method of methylating a catalyst composition while substantially normalizing the entiomeric distribution is provided. The method includes slurrying the organometallic compound in dimethoxyethane (DME), and adding a solution of RMgBr in DME, wherein R is a methyl group or a benzyl group, and wherein the RMgBr is greater than about 2.3 equivalents relative to the organometallic compound. After the addition of the RMgBr, the slurry is mixed for at least about four hours. An alkylated organometallic is isolated, wherein the methylated species has a meso/rac ratio that is between about 0.9 and about 1.2.