Abstract: Impact-modified polymeric materials are produced by visbreaking certain reactor blends. In a preferred embodiment, impact-modified polypropylene materials are produced by visbreaking a reactor blend of polypropylene and thermoplastic polyethylene. The polypropylene material is preferably homopolypropylene having a melt flow rate of less than about 1 dg/min. Such impact-modified polymeric materials manifest unexpected compatibility characteristics, increased impact resistance at low temperatures, improved antiblush characteristics and improved flow characteristics.

Abstract: A modified polypropylene having a substantially isotactic homopolypropylene and a propylene/olefin random copolymer, the modified polypropylene including up to about 50 chain disruptors per 1000 propylene repeat units. The chain disruptors are racemic polypropylene diads and olefin, the olefin being incorporated into the high end of the molecular weight distribution of the modified polypropylene.

Abstract: An ethylene polymer composition is provided, the composition being a blend of a first ethylene polymer and a second ethylene polymer, the second ethylene polymer characterized by molecules having long chain Y-branches. The blend can be prepared by an extrusion process in which a portion of the polyethylene fed to the process is irradiated and the irradiated and non-irradiated polymers are blended by melt extrusion. The blends exhibit high flow activation energies and good blow-molding properties.

Abstract: A novel polymer and polymer treatment method are provided. The method involves irradiation of a polymer under non-gelling conditions at a temperature above the polymer melting temperature and in the absence of oxygen. The polymer is characterized by a unique long chain Y-branched molecular structure.

Abstract: A process for copolymerizing ethylene with another monoolefin is described wherein the other monoolefin is incorporated into the polymer at very high efficiencies and in several instances the copolymer produced contains a higher concentration of the comonomer than the gas phase in the polymerization zone. A novel ethylene/1-hexene copolymer having very high relative comonomer dispersities (99% or higher, and even above 100%) is also described.

Abstract: The addition of a nitrite-sorbate stabilizing system to a copolymer of a conjugated diene and a monovinyl-substituted aromatic hydrocarbon improves thermal stability and suppresses gel and fisheye formation.