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以多官能度锂(简称Li)为引发剂,在不同条件下合成了3种星形苯乙烯(St)-异戊二烯(Ip)-丁二烯(Bd)三元共聚物,分析了共聚物的结构。结果表明,两次投料法的产物为两嵌段共聚物,低R[四氢呋喃(THF)与Li的摩尔比]值合成的聚异戊二烯(PI)链段的玻璃化转变温度(Tg)为-58.3℃,1,4-结构为83.8%;高R值合成的无规共聚段的Tg为-36.2℃。低R值一次投料法产物为多嵌段共聚物,-69℃为Bd-Ip无规共聚段的Tg,1,4-结构含量高;22.7℃为Ip-St共聚段的Tg,含摩尔分数为6.6%的PS嵌段。高R值一次投料法的产物为三元无规共聚物,1,4-结构含量低,只有1个Tg,为-28.9℃。
Three kinds of star-shaped isoprene (Ip) -butadiene (Bd) terpolymers were synthesized under different conditions using polyfunctional lithium (Li) as initiator. The structure of the copolymer. The results show that the glass transition temperature (Tg) of polyisoprene (PI) synthesized by two feeding methods is the diblock copolymer with low R [molar ratio of THF to Li] -58.3 ° C, and the 1,4-structure was 83.8%. The Tg of the random copolymerization section with high R value was -36.2 ° C. The product with a low R value was a multi-block copolymer with a Tg of -69 ° C at the Bd-Ip random copolymerization stage and a high 1,4-content of the copolymer; Tg of 22.7 ° C was the Tg of the Ip-St copolymerization stage, 6.6% of the PS block. The product of the high R value feedstock method is a ternary random copolymer with a low 1,4-content and only one Tg of -28.9 ° C.