Copolymerization behavior of Cp2ZrCl2/MAO and [(CO)5WC(Me)OZrCp2Cl]/MAO: a comparative study on ethylene/1-pentene copolymers |
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Authors: | Nyambeni Luruli,Lars-Christian Heinz,Robert Brü ll,Helgard G. Raubenheimer |
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Affiliation: | a Department of Chemistry and Polymer Science, University of Stellenbosch, Private Bag X1, 7602 Matieland, South Africa b Deutsches Kunststoff-Institut (German Institute for Polymers), Schloßgartenstr. 6, 64289 Darmstadt, Germany |
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Abstract: | Ethylene/1-pentene copolymers were synthesized using Cp2ZrCl2(1)/MAO and [(CO)5WC(Me)OZr(Cp)2Cl](2)/MAO catalyst systems. The copolymers were characterized by SEC, DSC, FTIR and 13C NMR spectroscopy. The copolymers synthesized with [(CO)5WC(Me)OZr(Cp)2Cl](2)/MAO had higher average molecular weights and broader polydispersities compared to those produced with Cp2ZrCl2(1)/MAO. The chemical heterogeneity was investigated by SEC-FTIR and fractionation techniques. All copolymers showed a higher incorporation of the 1-pentene in the low molecular weight fraction as revealed by SEC-FTIR. Crystallization analysis fractionation (CRYSTAF) showed a broad chemical composition distribution (CCD) for all the copolymers synthesized with these two catalyst systems. Selected copolymers were also analyzed using an automated preparative molecular weight fractionation. |
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Keywords: | Ethylene/1-pentene copolymers Short chain branching distribution (SCBD) Automated preparative molecular weight fractionation (PMWF) |
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