Modified conjugated diene-based polymer and rubber composition including the same
A modified conjugated diene-based polymer, and more particularly, a modified conjugated diene-based polymer having a unimodal molecular weight distribution curve measured by gel permeation chromatography (GPC), molecular weight distribution (PDI; MWD) of less than 1.7, and a Si content of 100 ppm or more based on weight, and including a repeating unit derived from an aromatic vinyl monomer in an amount from 15 wt % to less than 30 wt %, and a 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),
molecular weight distribution (PDI; MWD) of less than 1.7,
a Si content of 100 ppm or more based on a total weight of the modified conjugated diene-based polymer,
the modified conjugated diene-based polymer comprising a repeating unit derived from an aromatic vinyl monomer in an amount of 15 wt % or more and less than 30 wt % based on the total weight of the modified conjugated diene-based polymer, and
wherein the Si content is measured by an inductively coupled plasma analysis method,
wherein the modified conjugated diene-based polymer is prepared by:
(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.
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 has an affinity with silica.
4. The modified conjugated diene-based polymer of claim 3 , wherein the alkoxysilane-based modifier comprises one or more heteroatoms including a nitrogen atom, an oxygen atom, and a sulfur atom.
5. The modified conjugated diene-based polymer of claim 2 further comprising, a repeating unit derived from a diene-based monomer of 1 to 10 carbon atoms in an amount greater than 0 wt % to 1 wt %.
6. 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.
7. The modified conjugated diene-based polymer of claim 1 , wherein the molecular weight distribution (PDI; MWD) is from 1.0 to less than 1.7.
8. The modified conjugated diene-based polymer of claim 1 , wherein a Mooney viscosity of the modified conjugated diene-based polymer is 30 or more at 100° C.
9. The modified conjugated diene-based polymer of claim 8 , wherein the Mooney viscosity is 40 to 150 at 100° C.
10. A rubber composition comprising the modified conjugated diene-based polymer according to claim 1 , and a filler.
11. The rubber composition of claim 10 , 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.
12. The rubber composition of claim 11 , wherein the filler is a silica-based filler or a carbon black-based filler.
13. The rubber composition of claim 12 further comprising, a silane coupling agent, and wherein the filler is the silica-based filler.
14. The modified conjugated diene-based polymer of claim 1 , wherein the Si content is 100 ppm to 10,000 ppm based on the total weight of the modified conjugated diene-based polymer.
15. 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.
16. The method according to claim 15 , wherein the polymerization of step (S1) is conducted in a temperature range of 80° C. or less.
17. The method according to claim 15 , wherein the modifier is an alkoxysilane-based modifier comprising one or more heteroatoms including a nitrogen atom, an oxygen atom, and a sulfur atom.