Metallocene catalyzed branched polyolefin copolyners

Geldenhuys, Monja (1999-12)

Thesis (M.Sc.) -- University of Stellenbosch, 1999.

Thesis

ENGLISH ABSTRACT: This study concerns the copolymerization of ethylene and propylene with I-pentene using metallocene-based zirconium catalysts. A thorough study on the background of the copolymerizations of I-pentene with ethylene and propylene was done. The metallocene catalyst that was used in the copolymerization of ethylene with I-pentene was the isospecific rac-[ethylene bis(l-indenyl)]zirconium dichloride (rac-Et(Ind)2ZrCl2) catalyst, and in the copolymerization of propylene with I-pentene the 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 thermal properties, microstructures, molecular masses and molecular mass distributions. In particular the relationship of the amount of I-pentene incorporated in the copolymers on the thermal properties was investigated. The short-chain branching of these copolymers was investigated by crystallization analysis fractionation (CRYSTAF).

AFRIKAANSE OPSOMMING: Hierdie studie behels die kopolimerisasie van etileen en propileen met I-pentene deur van homogene metalloseenkatalisatore gebruik te maak. 'n Deeglike studie oor die agtergrond van die kopolimerisasie reaksies van I-pentene met etileen en propileen is gedoen. Die metalloseenkatalisatore wat gebruik is vir die kopolimerisasie van etileen met I-penteen en propileen met I-penteen is die isospesifieke rac-[etileen bis(l-indeniel)] zirkonium dichloried (rac-Et(Ind)2ZrCl2) katalisator en die silileen-gebrugde katalisator, rac-Me2Si(2-MeBenz[e]Ind)2ZrCl2, respektiewelik. Metielalumoksaan (MAO) is as ko-katalisator in al die polimerisasie reaksies gebruik. Karakterisering van die kopolimere het die berekening van die termiese eienskappe, mikrostrukture, molekulere massas en molekulere massa verspreidings behels. Daar is veral gekyk na die invloed van die hoeveelheid I-penteen geinkorporeer op die termiese eienskappe van die kopolimeer. Die kort-kettingvertakkings van die kopolimere is ondersoek deur die kristallisasie analise fraktioneringstegniek (CRYSTAF).

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/51339
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