The influence of polymerization conditions on the structure and properties of high molecular weight polyethylene obtained on supported vanadium catalyst system

摘要

During a slurry polymerization of ethylene, the influence of the molar ratio of the catalyst components and the pressure on the activity of an amorphous SiO2-supported vanadium containing catalyst system is investigated. (C2H5)(2)AlCl is used as a first co;catalyst and (C4H9)(1.5)(C8H17)(0.5) Mg as a second one. It is shown that using only the first co-catalyst the polymers obtained have a uniform structure consisting of compact angular particles. When both co-catalysts are used the polymers have a heterogeneous structure-spherulitic aggregates are also observed. Based on the differences established in the morphology of the polyethylenes an explanation is given for the influence of the second co-catalyst on the catalytic activity as well as for the peculiarities of the synthesized polymers in comparison with the commercial products. (C) 1997 Elsevier Science Ltd.