Abstract: A thermoplastic elastomer is provided comprising a branched olefin polymer having crystalline sidechains and an amorphous backbone wherein at least 90 mole percent of the sidechains are isotactic or syndiotactic polypropylene and at least 80 mole percent of the backbone is atactic polypropylene. Additionally, a process is provided for producing a thermoplastic elastomer composition comprising: a) contacting, in solution, at a temperature from about 90° C. to about 120° C., propylene monomers with a catalyst composition comprising a chiral, stereorigid transition metal catalyst compound capable of producing isotactic or syndiotactic polypropylene; b) copolymerizing the product of a) with propylene and, optionally, one or more copolymerizable monomers, in a polymerization reactor using an achiral transition metal catalyst capable of producing atactic polypropylene; and c) recovering a branched olefin polymer.

Abstract: Thermoplastic elastomers having improved processability are prepared by incorporating one or more organic sulfate or sulfonate salts into blends of thermoplastic polymers and olefinic rubber and melt processing the mixture. The rubber component of the mixture is preferably at least partially cured.

Abstract: A thermoplastic elastomer is provided comprising a branched olefin polymer having crystalline sidechains and an amorphous backbone wherein at least 90 mole percent of the sidechains are isotactic or syndiotactic polypropylene and at least 80 mole percent of the backbone is atactic polypropylene. Additionally, a process is provided for producing a thermoplastic elastomer composition comprising: a) contacting, in solution, at a temperature from about 90° C. to about 120° C., propylene monomers with a catalyst composition comprising a chiral, stereorigid transition metal catalyst compound capable of producing isotactic or syndiotactic polypropylene; b) copolymerizing the product of a) with propylene and, optionally, one or more copolymerizable monomers, in a polymerization reactor using an achiral transition metal catalyst capable of producing atactic polypropylene; and c) recovering a branched olefin polymer.

Abstract: The invention relates to a thermoplastic elastomer composition comprising a branched olefin copolymer derived from olefinically unsaturated monomers capable of insertion polymerization having A) a T.sub.g as measured by DSC less than or equal to 10.degree. C.; B) T.sub.m greater than 80.degree. C.; C) an elongation at break of greater than or equal to 300%; D) a tensile strength of greater than or equal to 1,500 psi (10,300 kPa); and E) an elastic recovery of greater than or equal to 50%. The invention also relates to process for preparing the invention composition comprising: A) polymerizing ethylene or propylene and optionally, one or more copolymerizable monomers in a polymerization reaction under conditions sufficient to form copolymer having greater than 40% chain end-group unsaturation; B) copolymerizing the product of A) with ethylene and one or more comonomers so as to prepare said branched olefin copolymer.

Abstract: The invention is a polyethylene composition having a polydispersity index of less than or equal to 3, an average branching index (g') as measured by GPC/Vis.gtoreq.0.9, and a melt strength (MS) (centiNewton, 190.degree. C.) that satisfies the relationship: ##EQU1## In a preferred embodiment these polyethylene compositions comprise A) branched polyethylene copolymers prepared by insertion polymerization of ethylene, ethylene-containing macromers, and optionally, additional copolymerizable monomers, and B) essentially linear ethylene copolymers. Improved melt strength without sacrificing the benefits of narrow polydispersity index are exhibited by the invention compositions.