Provided is a polyfunctional vinyl aromatic copolymer having reactivity and solubility that can be used for manufacturing a copolymer rubber and a copolymer rubber material having processability, strength and homogeneity obtained therefrom. The polyfunctional vinyl aromatic copolymer includes: 0.5 mol % or more and 40 mol % or less of a structural unit (a) derived from a divinyl aromatic compound and 60 mol % or more and 99.5 mol % or less of a structural unit (b) derived from a monovinyl aromatic compound, in which at least some of the structural units (a) are a crosslinked structural unit (a2) represented by the following Formula (2) and a vinyl-group-containing structural unit (a1) represented by the following Formula (1):

##STR00001##

in the formulas, R.sup.1's independently represent an aromatic hydrocarbon group having 6 to 30 carbon atoms.

A rubber composition for a tire containing a cyclopentene ring-opening polymer and a solution polymerized styrene-butadiene rubber. The rubber composition is a cross-linked rubber with excellent wet grip and low heat buildup properties.

A rubber composition for a tire containing a cyclopentene ring-opening polymer and a solution polymerized styrene-butadiene rubber. The rubber composition is a cross-linked rubber with excellent wet grip and low heat buildup properties.

Provided are a transition metal compound for an olefin polymerization catalyst, an olefin polymerization catalyst containing the transition metal compound, and a polyolefin prepared using the olefin polymerization catalyst for polymerization thereof, wherein the transition metal compound is represented by Chemical Formula A1 or Chemical Formula B1.

Provided are a transition metal compound for an olefin polymerization catalyst, an olefin polymerization catalyst containing the transition metal compound, and a polyolefin prepared using the olefin polymerization catalyst for polymerization thereof, wherein the transition metal compound is represented by Chemical Formula A1 or Chemical Formula B1.

A method for producing highly reactive olefin polymers wherein at least 50 mol % of the polymer chains have terminal double bonds, and a novel polymerization initiating system for accomplishing the same includes contacting isobutene or an isobutene-containing monomer mixture, wherein a Lewis acid catalyst is complexed with an oxygen and/or sulfur-containing Lewis base, in an apolar solvent, and wherein an initiator is employed to initiate polymerization of the isobutene or isobutene-containing monomer mixture.

A method for producing highly reactive olefin polymers wherein at least 50 mol % of the polymer chains have terminal double bonds, and a novel polymerization initiating system for accomplishing the same includes contacting isobutene or an isobutene-containing monomer mixture, wherein a Lewis acid catalyst is complexed with an oxygen and/or sulfur-containing Lewis base, in an apolar solvent, and wherein an initiator is employed to initiate polymerization of the isobutene or isobutene-containing monomer mixture.

A method for preparing polybutene includes the steps of: supplying a C4 mixture to an isomerization reactor in which (i) 1-butene is isomerized into 2-butene by a hydrogen isomerization reaction using an isomerization catalyst in an isomerization zone of the isomerization reactor and (ii) iso-butene and 2-butene are separated by fractional distillation in a fractional distillation zone; supplying a C4 mixture containing 2-butene which is separated in the isomerization reactor to a skeletal isomerization reactor, in which a part of normal-butene is skeletal isomerized into iso-butene by a skeletal isomerization reaction using a skeletal isomerization catalyst, and the obtained skeletal isomerization mixture is supplied and recycled to the isomerization reactor; and supplying (i) a raw material containing the iso-butene of high concentration and which is separated from the isomerization reactor and (ii) a polymerization catalyst to a polybutene polymerization reactor and thereby producing polybutene by a polymerization reaction.

A method for preparing polybutene includes the steps of: supplying a C4 mixture to an isomerization reactor in which (i) 1-butene is isomerized into 2-butene by a hydrogen isomerization reaction using an isomerization catalyst in an isomerization zone of the isomerization reactor and (ii) iso-butene and 2-butene are separated by fractional distillation in a fractional distillation zone; supplying a C4 mixture containing 2-butene which is separated in the isomerization reactor to a skeletal isomerization reactor, in which a part of normal-butene is skeletal isomerized into iso-butene by a skeletal isomerization reaction using a skeletal isomerization catalyst, and the obtained skeletal isomerization mixture is supplied and recycled to the isomerization reactor; and supplying (i) a raw material containing the iso-butene of high concentration and which is separated from the isomerization reactor and (ii) a polymerization catalyst to a polybutene polymerization reactor and thereby producing polybutene by a polymerization reaction.

A process for production of polyisobutylene includes subjecting a reaction admixture comprising isobutylene, a diluent for the isobutylene, which may be isobutane, and a catalyst composition, that may include a BF.sub.3/methanol catalyst complex, to reaction conditions suitable for causing at least a portion of the isobutylene to undergo polymerization to form a polyisobutylene product including polyisobutylene molecules. At least a fraction of the polyisobutylene molecules thus produced have alpha position double bonds and the polyisobutylene product has a number average molecular weight (M.sub.N) and a polydispersity index (PDI). The concentration of the diluent in the reaction admixture may be manipulated to control or change any one or more of (a) the relative size of the fraction, (b) the number average molecular weight of the product, (c) the polydispersity index of the product and (d) the relative size of the portion. The diluent concentration may be held constant to maintain any one or more of such characteristics constant.