Disclosed are an anionic polymerization initiator, which is a reaction product of an organometallic compound and a compound including an alkyl chain having a tertiary amino functional group, and a method of preparing a conjugated diene-based copolymer using the same.

A method for preparing cis-1,4-polydienes, the method comprising the steps of preparing a preformed, active lanthanide-based catalyst, aging the active lanthanide-based catalyst for more than 5 days to thereby formed an aged catalyst, and introducing the aged catalyst and conjugated diene monomer to be polymerized to thereby form an active polymerization mixture in which the conjugated diene monomer is polymerized to form a polydiene having a reactive chain end.

A method for preparing cis-1,4-polydienes, the method comprising the steps of preparing a preformed, active lanthanide-based catalyst, aging the active lanthanide-based catalyst for more than 5 days to thereby formed an aged catalyst, and introducing the aged catalyst and conjugated diene monomer to be polymerized to thereby form an active polymerization mixture in which the conjugated diene monomer is polymerized to form a polydiene having a reactive chain end.

A 1,4-cis polydiene formed by polymerizing at least a 1,3-butadiene monomer in the presence of a lanthanide catalyst system and a bis-diene additive.

A 1,4-cis polydiene formed by polymerizing at least a 1,3-butadiene monomer in the presence of a lanthanide catalyst system and a bis-diene additive.

A bimetallic catalytic system consists of the metallic components of formulae RLi and Ca(AR.sub.y).sub.2(L).sub.x in which: R represents a substituted or unsubstituted C.sub.1-C.sub.10 aliphatic radical, a substituted or unsubstituted C.sub.6-C.sub.20 aromatic radical or a substituted or unsubstituted C.sub.1-C.sub.10 heteroaliphatic radical; A denotes N or C; y has the value 2 when A is N and the value 3 when A is C; each R represents a hydrogen atom, a substituted or unsubstituted C.sub.5-C.sub.10 aliphatic radical, a substituted or unsubstituted C.sub.6-C.sub.20 aromatic radical, a substituted or unsubstituted silyl radical, a C.sub.1-C.sub.10 aliphatic radical substituted by at least one substituted or unsubstituted silyl radical, a C.sub.6-C.sub.20 aromatic radical substituted by at least one substituted or unsubstituted silyl radical; L represents a ligand; and x is a number ranging from 0 to 4.

A bimetallic catalytic system consists of the metallic components of formulae RLi and Ca(AR.sub.y).sub.2(L).sub.x in which: R represents a substituted or unsubstituted C.sub.1-C.sub.10 aliphatic radical, a substituted or unsubstituted C.sub.6-C.sub.20 aromatic radical or a substituted or unsubstituted C.sub.1-C.sub.10 heteroaliphatic radical; A denotes N or C; y has the value 2 when A is N and the value 3 when A is C; each R represents a hydrogen atom, a substituted or unsubstituted C.sub.5-C.sub.10 aliphatic radical, a substituted or unsubstituted C.sub.6-C.sub.20 aromatic radical, a substituted or unsubstituted silyl radical, a C.sub.1-C.sub.10 aliphatic radical substituted by at least one substituted or unsubstituted silyl radical, a C.sub.6-C.sub.20 aromatic radical substituted by at least one substituted or unsubstituted silyl radical; L represents a ligand; and x is a number ranging from 0 to 4.

The present disclosure provides a preparation method of a homogeneous rare earth catalyst. In the present disclosure, a depolymerizing agent is introduced into the homogeneous rare earth catalyst to promote complete depolymerization of an alkyl aluminum trimer into monomolecular alkyl aluminum. As a result, there is an increase in the number of the alkyl aluminum which serves as an effective chain transfer agent, resulting in a greatly improved chain transfer rate, such that a polymerization system has completed the chain transfer in an early stage of the reaction. Accordingly, an aluminum terminal molecular chain has an increased concentration, leading to an accelerated exchange with an active center propagating chain and a decreased influence caused by an increased viscosity of the system, maintaining living polymerization of the system.

The present disclosure provides a preparation method of a homogeneous rare earth catalyst. In the present disclosure, a depolymerizing agent is introduced into the homogeneous rare earth catalyst to promote complete depolymerization of an alkyl aluminum trimer into monomolecular alkyl aluminum. As a result, there is an increase in the number of the alkyl aluminum which serves as an effective chain transfer agent, resulting in a greatly improved chain transfer rate, such that a polymerization system has completed the chain transfer in an early stage of the reaction. Accordingly, an aluminum terminal molecular chain has an increased concentration, leading to an accelerated exchange with an active center propagating chain and a decreased influence caused by an increased viscosity of the system, maintaining living polymerization of the system.