The invention provides a modified liquid diene polymer that allows a rubber composition to give a crosslinked product which contains a filler in a dispersed state ideal for attaining enhanced properties and which also exhibits excellent properties such as wet grip and abrasion resistance. The invention also provides a rubber composition including the modified liquid diene polymer, a crosslinked product thereof, and a tire which includes a portion including the composition or the crosslinked product. The modified liquid diene polymer is a product of modification, with a specific silane compound, of a liquid diene block copolymer including a polymer block (b1) or (b1) containing butadiene units and a polymer block (b2) or (b2). The modified liquid diene polymer has a functional group derived from the silane compound, and satisfies specific conditions.

The present invention relates to a rubber composition having excellent tensile properties and viscoelasticity properties and including a modified conjugated diene-based polymer. The rubber composition may include a modified conjugated diene-based polymer which is selected considering target tensile properties and viscoelasticity properties, by predicting in advance the correlation of the modification ratio of the modified conjugated diene-based polymer and the dynamic viscoelasticity loss coefficient at 60 C. of the rubber composition through Mathematical Formula 1 and Mathematical Formula 2. Therefore, excellent compounding properties may be shown.

A sulfur-crosslinkable rubber mixture comprising at least the following constituents: at least one diene rubber and at least one liquid, linear modified diene polymer A, modified with a functional group of formula I) at only one chain end, the number of functional groups per molecule being on average from 0.8 to 1

(R.sup.1R.sup.2R.sup.3)SiXNHC(O)O,I)

where R.sup.1, R.sup.2 and R.sup.3 independently of one another are selected from methoxy groups, ethoxy groups, phenoxy groups, methyl groups, ethyl groups and phenyl groups, with in each case at least one of the groups R.sup.1, R.sup.2 and R.sup.3 being a methoxy group, an ethoxy group or a phenoxy group, and where X is a divalent alkyl group having 1 to 6 carbon atoms.

A sulfur-crosslinkable rubber mixture comprising at least the following constituents: at least one diene rubber and at least one liquid, linear modified diene polymer A, modified with a functional group of formula I) at only one chain end, the number of functional groups per molecule being on average from 0.8 to 1

(R.sup.1R.sup.2R.sup.3)SiXNHC(O)O,I)

where R.sup.1, R.sup.2 and R.sup.3 independently of one another are selected from methoxy groups, ethoxy groups, phenoxy groups, methyl groups, ethyl groups and phenyl groups, with in each case at least one of the groups R.sup.1, R.sup.2 and R.sup.3 being a methoxy group, an ethoxy group or a phenoxy group, and where X is a divalent alkyl group having 1 to 6 carbon atoms.

An organic polymer comprising an organic polymer fragment and at least one S-alkylsilyl hydrocarbonthioate group or at least one S-alkylstannyl hydrocarbonthioate group bonded to the backbone of the organic polymer fragment through a CSi covalent bond and their methods or production are provided. The organic polymer backbone can be derived from the anionic polymerization of monomers containing CC unsaturation. The silicon or tin atom can be further bonded to two alkoxy groups, two hydrocarbon groups or to one alkoxy group and one hydrocarbon group.

The present invention provides an organosilicon compound that has a novel structure, that makes it possible to obtain a rubber material excellent in mechanical properties, fuel economy, and grip performance, and that is preferably obtained from a naturally occurring material; and a rubber composition comprising the organosilicon compound.

Disclosed herein are copolymers end-functionalized with functionalized silanes of specified structure, rubber compositions comprising the copolymer, and related processes for preparing the end-functionalized copolymer. The present disclosure also relates to tires having at least one component (e.g., a tread) containing the end-functionalized copolymer or a rubber composition thereof. The copolymer comprises 55-80% by weight of a conjugated diene monomer and 20-45% by weight of an aromatic vinyl monomer lacking any nitrogen substitution on its aromatic ring, wherein the total amount of conjugated diene monomer and aromatic vinyl monomer comprise 100% (of the total monomers in the copolymer), and the end-functionalization comprises at least one group having formula (I). ##STR00001##

Disclosed herein are copolymers end-functionalized with functionalized silanes of specified structure, rubber compositions comprising the copolymer, and related processes for preparing the end-functionalized copolymer. The present disclosure also relates to tires having at least one component (e.g., a tread) containing the end-functionalized copolymer or a rubber composition thereof. The copolymer comprises 55-80% by weight of a conjugated diene monomer and 20-45% by weight of an aromatic vinyl monomer lacking any nitrogen substitution on its aromatic ring, wherein the total amount of conjugated diene monomer and aromatic vinyl monomer comprise 100% (of the total monomers in the copolymer), and the end-functionalization comprises at least one group having formula (I). ##STR00001##

This invention relates to a process for forming a long-chain branched polymer and a long-chain branched polymer resulting from the process. The process comprises reacting (a) a polyolefin base polymer with (b) a coupling agent comprising a polymeric coupling agent, optionally blended with a molecular coupling agent, the polymeric coupling agent being a modified polyolefin having a reactive coupling group at one or more terminal ends of the modified polyolefin chain, to couple the polyolefin base polymer (a) with the coupling agent (b) to form a long-chain branched polymer having a long-chain branching and/or higher surface energy relative to the polyolefin base polymer.

The present disclosure relates to a modifier, and more particularly, to a modifier including a compound represented by Formula 1, and a method of preparing the same. Such modifier exhibits excellent dispersibility via hydrogen bonding with an inorganic filler when mixed therewith. The present disclosure also relates to a modified conjugated diene-based polymer and a method of preparing the modified conjugated diene-based polymer by using the modifier. The resulted modified conjugated diene-based polymer exhibits excellent processability, high tensile strength, high wear resistance, low rolling resistance, and high wet skid resistance.