Modified conjugated diene-based polymer and rubber composition including the same

1. A modified conjugated diene-based polymer having:

a unimodal molecular weight distribution curve measured by gel permeation chromatography (GPC),

a molecular weight distribution (PDI; MWD) of 1.0 or more and less than 1.7, and

a Si content of 100 ppm or more based on a total weight of the modified conjugated diene-based polymer,

wherein the modified conjugated diene-based polymer is a homopolymer comprising a repeat unit derived from a conjugated diene-based monomer.

2. The modified conjugated diene-based polymer of claim 1 , further comprising a repeating unit derived from a conjugated diene-based monomer and a functional group derived from a modifier.

3. The modified conjugated diene-based polymer of claim 2 , wherein the modifier is an alkoxysilane-based modifier.

4. The modified conjugated diene-based polymer of claim 1 , wherein the modified conjugated diene-based polymer has a number average molecular weight (Mn) of 1,000 g/mol to 2,000,000 g/mol, and a weight average molecular weight (Mw) of 1,000 g/mol to 3,000,000 g/mol.

5. The modified conjugated diene-based polymer of claim 1 , wherein a Mooney viscosity is 30 or more at 100° C.

6. A rubber composition comprising the modified conjugated diene-based polymer according to claim 1 , and a filler.

7. The rubber composition of claim 6 , wherein the rubber composition comprises 0.1 parts by weight to 200 parts by weight of the filler based on 100 parts by weight of the modified conjugated diene-based polymer.

8. The rubber composition of claim 6 , wherein the filler is a silica-based filler or a carbon black-based filler.

9. The rubber composition of claim 6 , wherein a Mooney viscosity is from 59 to 74 at 100° C.

10. A method for preparing the modified conjugated diene-based polymer of claim 1 comprising:

(S1) polymerizing a conjugated diene-based monomer, or an aromatic vinyl-based monomer and a conjugated diene-based monomer, in a hydrocarbon solvent including an organometallic compound to prepare an active polymer; and

(S2) reacting the active polymer prepared in (S1) with a modifier,

wherein the active polymer is coupled with an organometal,

the step (S1) is continuously performed in two or more polymerization reactors, and

a polymerization conversion ratio in a first polymerization reactor is 50% or less.

11. The method of claim 10 , wherein the polymerization of step (S1) is conducted in a temperature range of 80° C. or less.