A 4-methyl-1-pentene polymer (X) wherein a content of a constitutional unit derived from 4-methyl-1-pentene is 90 to 100% by mol; a content of a constitutional unit derived from at least one olefin selected from ethylene and an α-olefin, other than 4-methyl-1-pentene, having 3 to 20 carbon atoms is 0 to 10% by mol; and the 4-methyl-1-pentene polymer satisfies certain requirements (a) to (f): (a) a meso diad fraction (m) measured by .sup.13C-NMR falling within a certain range; (b) a ratio of weight-average molecular weight Mw within a certain range; (c) a melt flow rate (MFR) within a certain range; (d) a cumulative weight fraction within a certain range; (e) a proportion of a polymer having a molecular weight of a certain range; and (f) a heat of fusion and a melting point of the 4-methyl-1-pentene polymer within certain ranges.

A 4-methyl-1-pentene polymer (X) wherein a content of a constitutional unit derived from 4-methyl-1-pentene is 90 to 100% by mol; a content of a constitutional unit derived from at least one olefin selected from ethylene and an α-olefin, other than 4-methyl-1-pentene, having 3 to 20 carbon atoms is 0 to 10% by mol; and the 4-methyl-1-pentene polymer satisfies certain requirements (a) to (f): (a) a meso diad fraction (m) measured by .sup.13C-NMR falling within a certain range; (b) a ratio of weight-average molecular weight Mw within a certain range; (c) a melt flow rate (MFR) within a certain range; (d) a cumulative weight fraction within a certain range; (e) a proportion of a polymer having a molecular weight of a certain range; and (f) a heat of fusion and a melting point of the 4-methyl-1-pentene polymer within certain ranges.

Embodiments are directed to catalyst systems comprising: a procatalyst; and a co-catalyst dissolved in a non-halogenated aprotic hydrocarbon solvent, the co-catalyst comprising: a non-coordinating borate dianion having the formula: (III) and two cations, each cation being independently chosen from a cation according to formula (I) or formula (II).

Embodiments are directed to catalyst systems comprising: a procatalyst; and a co-catalyst dissolved in a non-halogenated aprotic hydrocarbon solvent, the co-catalyst comprising: a non-coordinating borate dianion having the formula: (III) and two cations, each cation being independently chosen from a cation according to formula (I) or formula (II).

An elastomeric composition and method incorporating a hydrocarbon polymer modifier with improved permanence. The composition comprises elastomer, filler and silane-functionalized hydrocarbon polymer modifier (Si-HPM) made in a pre-reaction adapted to couple the Si-HPM to the elastomer, filler or both, wherein the Si-HPM comprises an interpolymer of monomers chosen from piperylenes, cyclic pentadienes, aromatics, limonenes, pinenes, amylenes, and combinations thereof.

An elastomeric composition and method incorporating a hydrocarbon polymer modifier with improved permanence. The composition comprises elastomer, filler and silane-functionalized hydrocarbon polymer modifier (Si-HPM) made in a pre-reaction adapted to couple the Si-HPM to the elastomer, filler or both, wherein the Si-HPM comprises an interpolymer of monomers chosen from piperylenes, cyclic pentadienes, aromatics, limonenes, pinenes, amylenes, and combinations thereof.

A block copolymer composition is disclosed herein. In some embodiments, a block copolymer composition has a weight average molecular weight (M.sub.w) of 70,000 g/mol to 120,000 g/mol, a polydispersity index (PDI) of 1.0 to 2.0, a glass transition temperature (T.sub.g) of −55° C. to −30° C., and a melt index (MI), measured at 230° C. and a loading condition of 5 kg, of 0.2 g/10 minutes to 3.0 g/10 minutes. The block copolymer composition has excellent processability.

Unsaturated and hydrogenated polyalpha-olefin products can be made with a high selectivity toward vinylidenes and tri-substituted vinylenes combined, a high selectivity toward vinylidenes, and a low selectivity toward 1,2-di-substituted vinylenes by using a catalyst system comprising a metallocene compound having the following structure in the polymerization reaction: ##STR00001##

Unsaturated and hydrogenated polyalpha-olefin products can be made with a high selectivity toward vinylidenes and tri-substituted vinylenes combined, a high selectivity toward vinylidenes, and a low selectivity toward 1,2-di-substituted vinylenes by using a catalyst system comprising a metallocene compound having the following structure in the polymerization reaction: ##STR00001##

A modified conjugated diene-based polymer and a rubber composition including the same are disclosed herein. In some embodiments, a modified conjugated diene-based polymer includes a 1,2-vinyl bond content of 30.0 wt % or less with respect to a total weight of the modified conjugated diene-based polymer, wherein the polymer has a glass transition temperature of −90° C. to −50° C., a mooney viscosity of 50 to 100 measured by ASTM D1646, polydispersity index (PDI) of 1.5 to 3.5, and a mooney relaxation ratio of 0.7 or less when measured at 110° C.