Conjugated diene polymer comprising at least a conjugated diene monomer unit, the conjugated diene polymer has a number-average molecular weight (Mn) in terms of polystyrene of 1,000 to 1,000,000, a ratio (Mw/Mn) of a weight-average molecular weight (Mw) to the number-average molecular weight (Mn) of lower than 2.0 and the polymer bears a halogen atom at a terminal of the polymer chain. Method for producing the conjugated diene polymer comprises subjecting a monomer containing at least a conjugated diene to living radical polymerization using a polymerization initiator comprising a halogenocyclopentadienyl triorganophosphine η
2
-olefin ruthenium complex represented by formula (6) (and an organic halide.
共轭二烯聚合物包括至少一个共轭二烯单体单元,该共轭二烯聚合物的聚合度数平均分子量(Mn)以聚
苯乙烯为单位为1,000至1,000,000,重均分子量(Mw)与数均分子量(Mn)之比小于2.0,并且该聚合物在聚合物链的末端带有卤素原子。制备该共轭二烯聚合物的方法包括使用聚合
引发剂将至少含有一个共轭二烯的单体进行活性自由基聚合,所述聚合
引发剂包括一个卤代
环戊二烯基三有机膦η2-烯烃
钌配合物,其
化学式为(6)(和一个有机卤化物)。