| 摘要 |
PROBLEM TO BE SOLVED: To provide a copolymer which can provide a rubber composition in which the fuel-efficient property and the wet grip performance are improved in a good balance, and a pneumatic tire.SOLUTION: The copolymer is obtained by reacting an active terminal of a copolymer obtained by polymerizing a conjugated diene compound and a styrene derivative having an alkoxy group using a polymerization initiator represented by formula (I) with a silicon compound having a carbonyl group and/or an ether group. The weight average molecular weight Mw is 1.0×10-2.5×10. In the formula, d represents 0 or 1, and Rrepresents a 1-100C hydrocarbylene group, Rand Rrepresent a hydrocarbyl group which may have a substituent group or a trihydrocarbylsilyl group, or Rand Rjoin and represent a hydrocarbylene group which may have at least one kind of atom selected from the group consisting of a silicon atom, a nitrogen atom, and an oxygen atom as a hetero atom, and M represents an alkali metal atom. |
