A modified polymer is obtained by grafting at least one compound of formula (I) to at least one unsaturation of the chain of an initial polymer

##STR00001##

in which Q represents a dipole comprising at least one nitrogen atom; A represents an arenediyl ring, optionally substituted by one or more hydrocarbon-based chains, which are identical or different, independent of one another, and are optionally substituted or interrupted by one or more heteroatoms; E represents a divalent hydrocarbon-based bonding group which may optionally contain one or more heteroatoms; R.sub.1, R.sub.2 and R.sub.3 represent, independently of one another, a hydrogen atom or a hydrocarbon-based chain which is optionally substituted or interrupted by one or more heteroatoms; and n is an integer having a value greater than or equal to 1.

The present invention relates to a process for producing PEG acrylate-HNBR copolymer which exhibits excellent processability by latex hydrogenation of PEG acrylate-NBR latex to afford PEG acrylate-HNBR latex and subsequent coagulation.

A xanthogen compound dispersion is formed by dispersing a xanthogen compound in water or alcohol, wherein a volume average particle size of the xanthogen compound is 0.001 to 9 μm.

A modified conjugated diene-based polymer represented by Formula 1, wherein a terminal of a polymer chain is modified, and a method for preparing same are provided. By including a modifier derived unit having a specific structure, a beta value affecting cold flow may be reduced through controlling the degree of branch, and accordingly, the cold flow of a polymer may be efficiently controlled and a mooney viscosity increasing ratio may be improved.

A modified natural rubber has a branching degree of 0.40 to 0.70 and includes a linking structure represented by formula (C), the linking structure having been formed by allowing polyisoprene, having a structure represented by formula (A) and/or formula (B), to bind in the structure to an amino compound having two or more primary amino groups:

##STR00001##

wherein X represents a hydrogen atom or a methyl group, and Ps, which may be the same or different from each other, represent a polyisoprene unit;

W-(Q).sub.m  (C)

wherein W represents a residue obtained by removing amino end groups from the amino compound Q represents at least one selected from the group consisting of the following general formulae (Q-1) to (Q-4), and m represents 2 to 4;

##STR00002##

wherein *.sup.1 indicates binding to a carbon atom of a polyisoprene unit, and *.sup.2 indicates binding to a carbon atom of the residue represented by W.

An end-modified diene polymer having excellent mechanical properties and a method for producing the polymer are provided. An end-modified diene polymer having at least one of the structures represented by the following formulae (1) to (4) at the end thereof:

##STR00001##

wherein Rs which may be the same or different each represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, and m and l which may be the same or different, respectively, each represent an integer of 2 or more.

A rubber composition contains a diene rubber component and a reinforcing filler, the diene rubber component containing a styrene-butadiene copolymer component including at least one type of styrene-butadiene copolymer and satisfying: the bonded styrene content is from 5 to 50 wt. %; of components obtained by ozone decomposition, a content of a decomposed component V1 containing one 1,2-bonded butadiene-derived unit out of a total of 100 mol % of decomposed components containing styrene-derived unit(s) and/or the 1,2-bonded butadiene-derived unit(s) is not less than 25 mol %; of the components obtained by ozone decomposition, a content of a decomposed component S2V1 containing two of the styrene-derived units and one of the 1,2-bonded butadiene-derived unit out of a total of 100 mol % of the decomposed components containing the styrene-derived unit(s) and/or the 1,2-bonded butadiene-derived unit(s) is not less than 5 mol %; and a vinyl content of a butadiene moiety is not less than 50%.

The invention relates to polymeric-inorganic nanoparticle compositions and preparation processes thereof. The invention also relates to an additive and lubricant compositions comprising these polymeric-inorganic nanoparticle compositions, as well as to the use of these polymeric-inorganic nanoparticle compositions in an oil lubricant formulation to improve tribological performance, in particular to improve extreme pressure performance and friction reduction on metal parts.

A rubber composition contains a diene rubber component and a reinforcing filler, the diene rubber component containing a styrene-butadiene copolymer component including at least one type of styrene-butadiene copolymer and satisfying: the bonded styrene content is from 5 to 50 wt. %; of components obtained by ozone decomposition, a content of a decomposed component V1 containing one 1,2-bonded butadiene-derived unit out of a total of 100 mol % of decomposed components containing styrene-derived unit(s) and/or the 1,2-bonded butadiene-derived unit(s) is not less than 25 mol %; of the components obtained by ozone decomposition, a content of a decomposed component S2V1 containing two of the styrene-derived units and one of the 1,2-bonded butadiene-derived unit out of a total of 100 mol % of the decomposed components containing the styrene-derived unit(s) and/or the 1,2-bonded butadiene-derived unit(s) is not less than 5 mol %; and a vinyl content of a butadiene moiety is not less than 50%.

Provided is a rubber composition which contains a diene rubber and a reinforcing filler, and the diene rubber contains a styrene-butadiene copolymer component including at least one type of styrene-butadiene copolymer and satisfying the following requirements: (1) the bonded styrene content is from 5 to 50 wt. %; (2) among components obtained by ozone decomposition, a content of a decomposed component V1 containing one 1,2-bonded butadiene-derived unit out of a total of 100 mol % of decomposed components containing styrene-derived units and/or 1,2-bonded butadiene-derived units is not less than 25 mol %; (3) among components obtained by ozone decomposition, a content of a decomposed component S2V1 containing two styrene-derived units and one 1,2-bonded butadiene-derived unit out of a total of 100 mol % of decomposed components containing styrene-derived units and/or 1,2-bonded butadiene-derived units is less than 5 mol %; and (4) a vinyl content of a butadiene moiety is not less than 50%.