Metallocene catalyzed branched polyolefin copolyners

[摘要] ENGLISH ABSTRACT: This study concerns the copolymerization of ethylene and propylene with I-penteneusing metallocene-based zirconium catalysts. A thorough study on the background ofthe copolymerizations of I-pentene with ethylene and propylene was done.The metallocene catalyst that was used in the copolymerization of ethylene withI-pentene was the isospecific rac-[ethylene bis(l-indenyl)]zirconium dichloride(rac-Et(Ind)2ZrCl2) catalyst, and in the copolymerization of propylene with I-pentenethe silylene-bridged catalyst, rac-Me2Si(2-MeBenz[e]Ind)2ZrCl2. Methylalumoxane(MAO) was used as cocatalyst in all the polymerizations.Characterization of these copolymers included determinations of the thermalproperties, microstructures, molecular masses and molecular mass distributions. Inparticular the relationship of the amount of I-pentene incorporated in the copolymerson the thermal properties was investigated. The short-chain branching of thesecopolymers was investigated by crystallization analysis fractionation (CRYSTAF).

[发布机构] Stellenbosch University