EFFECT OF INTERNAL LEWIS BASE ON ACTIVE SITE DISTRIBUTION FOR ETHYLENE/1-OCTENE COPOLYMERIZATION BY TICL4/LEWIS BASE/MGCL2 ATALYSTS

摘要

@@The molecular weight (MW) and polydispersity (PD) of polyethylene (PE) are important factors in determining the physical, mechanical, and rheological properties of polymers.1 Therefore, it is necessary to control the MW and PD to optimize the mechanical property and processibility of PE. The conventional Ziegler-Natta catalyst is still the main industrial catalysts for the production of PE. Hence, the control of PD of PE produced by using Ziegler-Natta catalyst has always been one of the most worthwhile research targets in both industrial and academic fields. Ziegler-Natta catalysts are basically multisite systems, and the PD of the polymer is dependent on the nature and distribution of the different active species in the catalyst. Lewis base (LB) component is one of the decisive factors that modifies the active sites, and thus affects the activity, stereospecificity, MW and PD.