The present invention disclosed a novel heterogeneous catalytic system (precatalyst), process for the preparation and use thereof for the synthesis of highly crystalline, disentangled ultra high molecular weight polyethylene (UHMWPE).

An ethylene/alpha-olefin copolymer that can be synthesized in a fluidized-bed, gas phase polymerization reactor and made into a blown film. The ethylene/alpha-olefin copolymer is characterized by a bubble stability-effective combination of properties comprising density, melt flow ratio (I.sub.21/I.sub.5), and melt storage modulus G (G=3,000 Pa). The synthesis in the FB-GPP reactor is characterized by a property-imparting-effective combination of operating conditions comprising reactor bed temperature and H2/C2 gas molar ratio. An embodiment of the blown film consisting of the ethylene/alpha-olefin copolymer is characterized by enhanced bubble stability. A method of making the ethylene/alpha-olefin copolymer. A film comprising the ethylene/alpha-olefin copolymer. A method of making the film. A manufactured article comprising the film.

An ethylene/alpha-olefin copolymer that can be synthesized in a fluidized-bed, gas phase polymerization reactor and made into a blown film. The ethylene/alpha-olefin copolymer is characterized by a bubble stability-effective combination of properties comprising density, melt flow ratio (I.sub.21/I.sub.5), and melt storage modulus G (G=3,000 Pa). The synthesis in the FB-GPP reactor is characterized by a property-imparting-effective combination of operating conditions comprising reactor bed temperature and H2/C2 gas molar ratio. An embodiment of the blown film consisting of the ethylene/alpha-olefin copolymer is characterized by enhanced bubble stability. A method of making the ethylene/alpha-olefin copolymer. A film comprising the ethylene/alpha-olefin copolymer. A method of making the film. A manufactured article comprising the film.

A dual reactor solution polymerization process gives high density polyethylene compositions containing a first ethylene copolymer and a second ethylene copolymer. The polyethylene compositions can be used in the manufacture of injection molded closures or cast film having good barrier properties.

A dual reactor solution polymerization process gives high density polyethylene compositions containing a first ethylene copolymer and a second ethylene copolymer. The polyethylene compositions can be used in the manufacture of injection molded closures or cast film having good barrier properties.

A method of independently changing a melt rheology property value of a bimodal polyethylene polymer being made using a bimodal catalyst system in a single gas phase polymerization reactor. The method comprises process conditions comprising alkane(s) in the reactor. The method comprises a bimodal catalyst system that is characterized by an inverse response to alkane(s) concentration. The method comprises changing concentration of the alkane(s) in the reactor by an amount sufficient to effect a measurable change in the melt rheology property value; wherein the bimodal catalyst system is characterized by an inverse response to alkane(s) concentration such that when the alkane(s) concentration is increased, the melt rheology property value of the resulting bimodal polyethylene polymer is decreased, and when the alkane(s) concentration is decreased, the melt rheology property value of the resulting bimodal polyethylene polymer is increased.

A method of independently changing a melt rheology property value of a bimodal polyethylene polymer being made using a bimodal catalyst system in a single gas phase polymerization reactor. The method comprises process conditions comprising alkane(s) in the reactor. The method comprises a bimodal catalyst system that is characterized by an inverse response to alkane(s) concentration. The method comprises changing concentration of the alkane(s) in the reactor by an amount sufficient to effect a measurable change in the melt rheology property value; wherein the bimodal catalyst system is characterized by an inverse response to alkane(s) concentration such that when the alkane(s) concentration is increased, the melt rheology property value of the resulting bimodal polyethylene polymer is decreased, and when the alkane(s) concentration is decreased, the melt rheology property value of the resulting bimodal polyethylene polymer is increased.

A triblock polymer of formula B-A-B is provided. According to the formula, the symbol A represents a central block which is a statistical copolymer comprising units of a 1,3-diene and more than 50 mol % of ethylene units. The symbols B each represent an end block which is a polyethylene with a melting point of greater than 90 C. and a number-average molar mass of greater than or equal to 2000 g/mol and less than or equal to 10 000 g/mol. The polymer has improved rheological properties relative to a statistical copolymer based on ethylene and 1,3-diene of the same microstructure without changing its mechanical and dynamic or thermal properties.

A triblock polymer of formula B-A-B is provided. According to the formula, the symbol A represents a central block which is a statistical copolymer comprising units of a 1,3-diene and more than 50 mol % of ethylene units. The symbols B each represent an end block which is a polyethylene with a melting point of greater than 90 C. and a number-average molar mass of greater than or equal to 2000 g/mol and less than or equal to 10 000 g/mol. The polymer has improved rheological properties relative to a statistical copolymer based on ethylene and 1,3-diene of the same microstructure without changing its mechanical and dynamic or thermal properties.

A polyethylene homopolymer composition comprises: a first ethylene homopolymer having a density, d.sup.1 of from 0.930 to 0.975 g/cm.sup.3, a melt index, I.sub.2.sup.1 of from 0.01 to 10 g/10 min, and a molecular weight distribution, Mw/Mn of less than 2.5; and a second ethylene homopolymer having a density, d.sup.2 of from 0.945 to 0.980 g/cm.sup.3, a melt index, I.sub.2.sup.2 of at least 1.0 g/10 min, and a molecular weight distribution, M.sub.w/M.sub.n of less than 2.5; wherein melt index, I.sub.2.sup.2 of the second ethylene homopolymer is greater than the melt index, I.sub.2.sup.1 of the first ethylene homopolymer. The polyethylene homopolymer compositions which may be nucleated have a weight average molecular weight, M.sub.w of ?75,000, a molecular weight distribution, M.sub.w/M.sub.n of less than 4.0 and may be usefully employed in molding applications, such as, for example, in compression molded closures.