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采用改性稀土催化体系Nd(oct)_3-Al(i-Bu)_3-CHCl_3(Nd-Al-Cl),以己烷为溶剂,进行了丁二烯(Bd)与苯乙烯(St)的共聚合。当催化剂中Al/Nd=10～20(摩尔比),Cl/Nd=10O～25(摩尔比),陈化温度为20～70℃。陈化时间为2～20h时,在St/Bd=0.7～2.0(摩尔比),聚合温度为30～60℃,聚合时间为10～20h的条件下,经催化聚合可得到Bd链段顺-1,4含量为90％～96％(摩尔),结合St含量为10％～15％(摩尔),[η]为0.8～1.2dL/g的丁苯共聚物。经IR,DSC及TEM检测表征,该丁苯共聚物的序列分布以嵌段为主,兼有无规分布。FRIR和UV研究表明,催化活性中心的形成是先由Cl与Al作用生成Al(i-Bu)_2 Cl,再与Nd进行交换和络合反应;而单体与活性中心的配位,则可能相应形成两种引发中心,并插入增长。
The modified rare earth catalytic system Nd (oct) _3-Al (i-Bu) _3-CHCl_3 (Nd-Al-Cl) Copolymerization. When the catalyst has Al / Nd = 10-20 (molar ratio) and Cl / Nd = 10O-25 (molar ratio), the aging temperature is 20-70 ° C. The aging time is 2 ~ 20h, under the conditions of St / Bd = 0.7 ~ 2.0 (molar ratio), the polymerization temperature is 30 ~ 60 ℃ and the polymerization time is 10 ~ 20h, 1,4 content of 90% to 96% by mole, and a styrene-butadiene copolymer having a St content of 10% to 15% by mole and a [η] of 0.8 to 1.2 dL / g. The results of IR, DSC and TEM showed that the sequence distribution of the styrene-butadiene copolymer was block-based, with random distribution. FRIR and UV studies have shown that the formation of catalytic activity centers firstly by the action of Cl and Al to form Al (i-Bu) 2 Cl, and then exchange and complex with Nd. However, the coordination between the monomer and the active site may be Correspondingly, two kinds of initiation centers are formed and inserted into growth.