论文部分内容阅读
将一种大环多烯化合物反,反,顺-1,5,9-环十二碳三烯((E,E,Z)-CDT)用于Ziegler-Natta催化体系和茂金属催化体系催化丙烯聚合,利用1H NMR和13C NMR方法考察了催化体系中加入(E,E,Z)-CDT后的丙烯聚合行为,分析了所得聚合物的微观结构,提出了(E,E,Z)-CDT提高催化剂立构选择性的机理。实验结果表明,(E,E,Z)-CDT难以与丙烯进行共聚反应,丙烯聚合反应中加入(E,E,Z)-CDT后,聚合活性下降明显。但在丙烯聚合反应中引入(E,E,Z)-CDT后可明显提高聚丙烯的等规度,且随(E,E,Z)-CDT用量的增大,聚合物的等规度提高。大环多烯化合物独特的多电子和大位阻结构,使其在丙烯聚合过程中通过“短程”和“长程”效应作用于催化剂活性中心,形成了其独特的影响丙烯聚合的能力。
Cyclo-1,5,9-cyclododecatriene ((E, E, Z) -CDT), a macrocyclic polyene compound, was used to catalyze the Ziegler-Natta catalysis and the metallocene catalysis (E, E, Z) -CDT was investigated by 1H NMR and 13C NMR. The microstructure of the obtained polymer was analyzed. The (E, E, Z) Mechanism of CDT to Increase Stereoselectivity of Catalysts. The experimental results show that (E, E, Z) -CDT is difficult to copolymerize with propylene, and the polymerization activity decreases obviously when (E, E, Z) -CDT is added in propylene polymerization. However, the incorporation of (E, E, Z) -CDT in propylene polymerization can significantly improve the isotacticity of polypropylene. With the increase of the amount of (E, E, Z) -CDT, the isotacticity of the polymer increases . The unique multi-electron and steric hindrance structures of macrocyclic polyene compounds make them play a key role in the active site of catalysts in the process of propylene polymerization through the effects of “short-range” and “long-range” ability.