Ziegler-Natta催化乙烯/长链1-烯烃共聚合——长链1-烯烃的共聚活性

COPOLYMERIZATION OF ETHYLENE WITH 1-ALKENES USING ZIEGLER-NATTA CATALYSTS

乙烯/1-烯烃共聚合是近年来活跃的研究课题之一,随1-烯烃种类不同及其在共聚物中含量的变化,共聚产物主要有橡胶弹性体(如乙丙胶)、线性低密度聚乙烯(LLDPE)等。研究结果表明,与短支链共聚单体相比,由长支链共聚单体获得的LLDPE具有更加优越的加工性能、整体韧性和抗撕裂性,由于侧基的位阻作用。

Copolymerization of ethylene with linear 1-alkenes in the presence of different Ziegler-Natta catalysts, TiCl3-AlEt2Cl,VOCl3-Al2Et3Cl3and Ti(VMgCl2-AlR3 ,at 30℃ were investigated, and reactivity ratios for all pairs ethylene-1-alkene were determined . It was found that, for heterogeneous catalysts, the copolymerization reactivity of linear 1-alkenes was greatly improved when a small amount of propylene was present in the polymerization, while for homogeneous catalyst VOCl3, no change was observed. It seems that a synergistic effect existed in the reactivities of propylene, linear 1-alkene and active site in the polymerization with ethylene.