A metal complex of the formula (1) TCyLMZ.sub.p (1), wherein M is a group 4 metal, Z is an anionic ligand, p is the number 1 or 2, TCy is a thiophene-fused cyclopentadienyl-type ligand of the formula (2) ##STR00001##
is described. Methods of making and using the metal complex are also described.

A metal complex of the formula (1) TCyLMZ.sub.p (1), wherein M is a group 4 metal, Z is an anionic ligand, p is the number 1 or 2, TCy is a thiophene-fused cyclopentadienyl-type ligand of the formula (2) ##STR00001##
is described. Methods of making and using the metal complex are also described.

A metal complex of the formula (1) TCyLMZ.sub.p (1), wherein M is a group 4 metal, Z is an anionic ligand, p is the number 1 or 2, TCy is a thiophene-fused cyclopentadienyl-type ligand of the formula (2) ##STR00001##
is described. Methods of making and using the metal complex are also described.

A crosslinked rubber composition contains ethylene-propylene-diene copolymer rubber crosslinked with a rotaxane compound having a cyclic molecule and an axial molecule penetrating through the cyclic molecule. In the crosslinked rubber composition, the ethylene-propylene-diene copolymer rubber contains vinylnorbornene, dicyclopentadiene, or tetrahydroindene as a diene component, and the rotaxane compound has a nitrile oxide group on the cyclic molecule and one end of the axial molecule, and the cyclic molecule is crown ether.

A crosslinked rubber composition contains ethylene-propylene-diene copolymer rubber crosslinked with a rotaxane compound having a cyclic molecule and an axial molecule penetrating through the cyclic molecule. In the crosslinked rubber composition, the ethylene-propylene-diene copolymer rubber contains vinylnorbornene, dicyclopentadiene, or tetrahydroindene as a diene component, and the rotaxane compound has a nitrile oxide group on the cyclic molecule and one end of the axial molecule, and the cyclic molecule is crown ether.

Provided herein are metallocene-catalyzed polymer compositions that exhibit advantageous rheological properties, at least some of which are consistent with long-chain branching, as well as polymerization processes suitable for forming such polymer compositions. The polymer compositions may have both LCB index measured at 125° C. of less than 5; and phase angle δ at complex shear modulus G*=100,000 Pa of less than about 54.5°, as determined at 125° C. The polymer compositions of particular embodiments are reactor blends, preferably of ethylene copolymers (e.g., ethylene-propylene (EP) copolymers and/or ethylene-propylene-diene (EPDM) terpolymers). The reactor blend may include first and second copolymer components, which may differ in monomer content and weight-average molecular weight (Mw).

Provided herein are metallocene-catalyzed polymer compositions that exhibit advantageous rheological properties, at least some of which are consistent with long-chain branching, as well as polymerization processes suitable for forming such polymer compositions. The polymer compositions may have both LCB index measured at 125° C. of less than 5; and phase angle δ at complex shear modulus G*=100,000 Pa of less than about 54.5°, as determined at 125° C. The polymer compositions of particular embodiments are reactor blends, preferably of ethylene copolymers (e.g., ethylene-propylene (EP) copolymers and/or ethylene-propylene-diene (EPDM) terpolymers). The reactor blend may include first and second copolymer components, which may differ in monomer content and weight-average molecular weight (Mw).

Provided herein are metallocene-catalyzed polymer compositions that exhibit advantageous rheological properties, at least some of which are consistent with long-chain branching, as well as polymerization processes suitable for forming such polymer compositions. The polymer compositions may have both LCB index measured at 125° C. of less than 5; and phase angle δ at complex shear modulus G*=100,000 Pa of less than about 54.5°, as determined at 125° C. The polymer compositions of particular embodiments are reactor blends, preferably of ethylene copolymers (e.g., ethylene-propylene (EP) copolymers and/or ethylene-propylene-diene (EPDM) terpolymers). The reactor blend may include first and second copolymer components, which may differ in monomer content and weight-average molecular weight (Mw).

A rubber composition is provided that contains an ethylene-butene-diene terpolymer, silica having a CTAB specific surface area of 30 m.sup.2/g or more and 150 m.sup.2/g or less, a silane coupling agent, and a crosslinking agent, in which a content of the silica per 100 parts by weight of the ethylene-butene-diene terpolymer is 25 parts by weight or more and 90 parts by weight or less.

A rubber composition is provided that contains an ethylene-butene-diene terpolymer, silica having a CTAB specific surface area of 30 m.sup.2/g or more and 150 m.sup.2/g or less, a silane coupling agent, and a crosslinking agent, in which a content of the silica per 100 parts by weight of the ethylene-butene-diene terpolymer is 25 parts by weight or more and 90 parts by weight or less.