Copolymerization of ethylene and 1-dodecene catalyzed by novel low-Ti-loading Ziegler-Natta catalysts and their microstructures

Ethylene-1-dodecene copolymers were synthesized with novel low-Ti-loading (0.8 wt%) Ziegler-Natta catalysts prepared by a one-pot balling method. ¹³C-NMR was applied for the quantitative determination of the composites and microstructures of the resultant ethylene-1-dodecene copolymers. The results showed that (1) the ethylene-1-dodecene copolymers obtained from both the MgCl₂-supported low-Ti-loading Ziegler-Natta catalyst and the MgCl₂/SiO₂-bisupported low-Ti-loading Ziegler-Natta catalyst at a 0.6M 1-dodecene concentration had high levels of 1-dodecene and (2) most of the 1-dodecene units were separated by ethylene units in the copolymer chains obtained from the MgCl₂-supported low-Ti-loading Ziegler-Natta catalyst, whereas there were some continuous 1-dodecene repeat units in the copolymer chain obtained from the MgCl₂/SiO ₂-bisupported low-Ti-loading Ziegler-Natta catalyst.