Effects of molecular dispersion state of surface Ti species on ethylene-propylene copolymerization with TiCl3-based Ziegler-Natta model catalyst

摘要: The dispersion state of surface Ti species is one the most important factors affecting polymerization properties MgCl2-supported heterogeneous Ziegler-Natta catalysts. In this paper, ethylene-propylene copolymerization was carried out using a novel model catalyst with “isolated” and “clustered” TiCl3 molecules on MgCl2. At lower ethylene/propylene feed ratio, strongly affected both composition sequence distribution copolymers. gave relatively random copolymer, clustering enhanced bulkiness. addition an external donor basically deteriorated character “isolated but degree deterioration depended type donors. On other hand, balance between monomer consumption dominated performance at higher ratio to obscure effects state.