Ziegler-Natta催化剂合成丙烯/α-烯烃共聚聚丙烯

Synthesis of propylene/α-olefin copolymers by Ziegler-Natta catalyst

采用Ziegler-Natta催化剂分别合成了丙烯/1-丁烯、丙烯/1-戊烯、丙烯/1-辛烯共聚聚丙烯。利用^13C NMR,XRD,DSC研究了共聚物的序列结构、晶型、熔点和结晶性能。实验结果表明,α-烯烃单体以孤立形式沿聚合物链呈无规分布,分布的均匀性随α-烯烃单体不同而有所差异,1-丁烯能最有效地阻断共聚物中丙烯单元的连续分布。少量α-烯烃共聚单体的插入不会引起丙烯聚合物晶型的改变,1-丁烯能更显著降低聚丙烯的熔点,且对聚丙烯结晶度的影响最小。

Ziegler-Natta catalyst was used to synthesize propylene/1-butene,propylene/1-pentene and propylene/1-octene copolymers.^13C NMR,XRD,and DSC were utilized to characterize the chain sequence structure,crystal type,and the melting and crystallization properties of the copolymers.The result shows that theα-olefin units are randomly distributed along the polypropylene chain,and the distribution uniformity varies with theα-olefin type.1-Butene can most effectively block the continuous distribution of propylene units in the copolymer.The insertion of a small amount ofα-olefin comonomer will not cause the change of propylene polymer crystal form.1-Butene significantly reduces the melting point of polypropylene,whereas its effect on the crystallinity of polypropylene is minimal.