Modified conjugated diene polymer, a modified rubber composition containing same, and method for preparing modified conjugated diene polymer

A method of preparing a modified conjugated diene-based polymer, comprising:

• a) polymerizing a conjugated diene monomer or a conjugated diene monomer and an aromatic vinyl monomer using a hydrocarbon solvent in presence of an organo-alkali metal compound, thus forming an active polymer having an alkali metal end;
• and
• b) coupling or linking the active polymer having the alkali metal end with a compound represented by Chemical Formula 1 below, yielding a modified conjugated diene-based polymer, which is a compound represented by Chemical Formula 2 below:
• wherein R1 is
• or a C1-C50 alkyl group, n is 1 to 20, and m is 0 to 20;
• and
• wherein R2 is
• or a C1-C50 alkyl group, Pn and Pm are polymers comprising a conjugated diene monomer and a conjugated aromatic monomer as main components, with a number average molecular weight of 1,000 to 10,000,000 g/mol, and including an acryl, amine, ether or thioether monomer, Pn and Pm are identical to or different from each other, a is 1 to 3, b is 0 to 3, n is 1 to 20, and m is 0 to 20.