烷氧基镁载体型Ziegler-Natta催化剂及其催化乙烯聚合

Ethoxymagnesium supported Ziegler-Natta catalyst and it for ethylene polymerization

以烷氧基镁为载体,添加多杂硅氧烷类给电子体得到烷氧基镁负载型Ziegler-Natta催化剂,通过预聚改变催化剂乙烯聚合行为,利用XPS、SEM、粒径分布等方法研究了催化剂和聚乙烯颗粒的性质。实验结果表明,三甲基硅基磷酸酯(ED1)和三甲基硅基硼酸酯(ED3)给电子体可提高催化剂的钛负载量和催化活性,当n(ED1)∶n(Mg(EtO)_2)=0.25时,常压活性与MgCl_2载体型催化剂相当。加入给电子体的催化剂均较好地保持了乙氧基镁载体颗粒的形态。乙氧基镁负载型催化剂催化乙烯聚合基本无活性,但预聚后进行乙烯聚合,活性可达13 700 g/g,添加ED1后活性提高至17 000 g/g。ED1和ED3均能显著提高催化剂活性,且聚合速率较稳定。

The Ziegler-Natta catalysts were prepared by the carrier Mg（EtO）2, TICl4 and mutlhetero siloxane electron donors. The influence of prepolymerization was studied. The structures and properties of the catalysts and the obtained polymers were characterized by XPS, SEM and particle size analyzer. The results showed that the tris（trimethylsilyl） phosphate（ED1） and tris（trimethylsilyl） borate（ED3 ） can increase Ti content and catalytic activity of catalysts. When n（ED 1） ： n（Mg（EtO）2） ratio is 0.25, the Mg（EtO）2 supported catalysts showed the same activity as MgCl2 supported catalysts. The catalysts can remain the shape of the Mg（EtO）2 carrier. Although the Mg（EtO）2 catalyst showed little activity in ethylene polymerization, its activity can reach 13 700 g/g after prepolymerization. Activity of the catalyst with ED 1 can increase to 17 000 g/g. Both ED 1 and ED3 can increase the activity of the catalyst, and the polymerization rates were stable.