A preparation method for a copolymer includes the step(s) of contacting an olefin and an unsaturated carboxylic acid shown in Formula II or a derivative of the unsaturated carboxylic acid shown in Formula II with a catalyst and optionally a chain transfer agent for reaction in the presence of an alkane solvent to obtain the copolymer. The copolymer is a spherical and/or spherical-like copolymer.

A preparation method for a copolymer includes the step(s) of contacting an olefin and an unsaturated carboxylic acid shown in Formula II or a derivative of the unsaturated carboxylic acid shown in Formula II with a catalyst and optionally a chain transfer agent for reaction in the presence of an alkane solvent to obtain the copolymer. The copolymer is a spherical and/or spherical-like copolymer.

Compositions may comprise symmetrical and asymmetrical pyridine-containing transition metal-complexes having appended group 13 Lewis acids positioned on the pyridine-containing ligands of the transition metal-complex such that the group 13 Lewis acid may be near the catalytic site, thereby allowing the appended group 13 Lewis acid to function more efficiently in promoting formation of a catalytically active species. Catalysts systems may comprise these symmetrical and asymmetrical pyridine-containing transition metal-complexes and methods of preparing polyolefins may use these catalyst systems.

Compositions may comprise symmetrical and asymmetrical pyridine-containing transition metal-complexes having appended group 13 Lewis acids positioned on the pyridine-containing ligands of the transition metal-complex such that the group 13 Lewis acid may be near the catalytic site, thereby allowing the appended group 13 Lewis acid to function more efficiently in promoting formation of a catalytically active species. Catalysts systems may comprise these symmetrical and asymmetrical pyridine-containing transition metal-complexes and methods of preparing polyolefins may use these catalyst systems.

The invention relates to a family of Pd(II)-based catalysts of general formula (I) reproduced below for use in the production of olefin/polar vinyl monomer copolymers and olefin homopolymers. The invention also refers to ligands that are intermediates in the synthesis of the catalysts, to the process for the synthesis of homo- and copolymers using these catalysts, and to the homo- and copolymers thus obtained. ##STR00001##

The invention relates to a family of Pd(II)-based catalysts of general formula (I) reproduced below for use in the production of olefin/polar vinyl monomer copolymers and olefin homopolymers. The invention also refers to ligands that are intermediates in the synthesis of the catalysts, to the process for the synthesis of homo- and copolymers using these catalysts, and to the homo- and copolymers thus obtained. ##STR00001##

The invention discloses an iron bipyridine complex, a preparation method of the same, and use of the same in polymerization of conjugated dienes the invention provides an iron bipyridine complex, which is used as a primary catalyst showing high activity in the polymerization of polyprene to obtain a polymer with a high branched-chain degree. The polymer has the characteristics of a high molecular weight and narrow molecular weight distribution, and the molecular weight of the polymer can be adjusted by a chain transfer reagent. The obtained poly(conjugated diene) rubber has high branched-chain content and an ultrahigh molecular weight. Because there are a large number of side groups on the molecular chains of the rubber, the rubber is mainly used for preparing high-performance tires and other related rubber products with good wet traction and low friction-induced heat generation.