Synthesis and properties of branched polyethylene/high-density polyethylene blends using a homogeneous binary catalyst system composed of early and late transition metal complexes

dc.contributor.authorKunrath, F. A.
dc.contributor.authorMauler, R. S.
dc.contributor.authorde Souza, R. F.
dc.contributor.authorCasagrande, O. L.
dc.contributor.institutionUniversidade Federal do Rio Grande do Sul (UFRGS)
dc.contributor.institutionUniversidade Estadual Paulista (Unesp)
dc.date.accessioned2014-05-20T15:26:57Z
dc.date.available2014-05-20T15:26:57Z
dc.date.issued2002-10-18
dc.description.abstractBranched polyethylene/high-density polyethylene blends (BPE/HDPE) with a wide range of molecular weights, melt flow indexes (MFI), and intrinsic viscosity were prepared using the homogeneous binary catalyst system composed by Ni(alpha-diimine)Cl-2 (1) (alpha-diimine = 1,4-bis(2,6-diisopropylphenyl)-acenaphthenediimine) and {Tp(Ms*)} TiCl3 (2) (Tp(Ms*)=hydridobis(3-mesitylpyrazol-1-yl)(5-mesityl-pyrazol-1-yl)) activated with MAO and/or TIBA in hexane at two different polymerization temperatures (30 and 55 degreesC) and by varying the nickel loading molar fraction (x(Ni)). At all Temperatures, a non-linear correlation between the x(Ni) and the productivity was observed, suggesting the occurrence of a synergistic effect between the nickel and the titanium catalyst precursors, which is more pronounced at 55 degreesC. The molecular weight of the BPE/HDPE blends considerably decreases with increasing Al/M molar ratio. The melt flow indexes (MFI) and intrinsic viscosities (eta) are strongly affected by x(Ni), but the melting temperatures are nearly constant, 132 +/- 3 degreesC. Dynamic mechanical thermal analysis (DMTA) shows the formation of different polymeric materials where the stiffness vanes according, to the x(Ni) and temperature used in the polymerization reaction. The surface morphology of the BPE/HDPE blends studied by scanning electron microscopy (SEM) revealed a low miscibility between the PE phases resulting in the formation of a sandwich structure after etching with o-xylene.en
dc.description.affiliationUFRGS, Inst Quim, Lab Mol Catalysis, BR-91501970 Porto Alegre, RS, Brazil
dc.description.affiliationUNESP, Inst Quim Araraquara, BR-14800900 Araraquara, SP, Brazil
dc.description.affiliationUnespUNESP, Inst Quim Araraquara, BR-14800900 Araraquara, SP, Brazil
dc.format.extent2058-2068
dc.identifierhttp://onlinelibrary.wiley.com/doi/10.1002/1521-3935%28200210%29203:14%3C2058
dc.identifier.citationMacromolecular Chemistry and Physics. Weinheim: Wiley-v C H Verlag Gmbh, v. 203, n. 14, p. 2058-2068, 2002.
dc.identifier.doi10.1002/1521-3935(200210)203:14<2058
dc.identifier.issn1022-1352
dc.identifier.urihttp://hdl.handle.net/11449/37022
dc.identifier.wosWOS:000179030400005
dc.language.isoeng
dc.publisherWiley-Blackwell
dc.relation.ispartofMacromolecular Chemistry and Physics
dc.relation.ispartofjcr2.492
dc.relation.ispartofsjr0,760
dc.rights.accessRightsAcesso restrito
dc.sourceWeb of Science
dc.subjectBPE/HDPE blendspt
dc.subjectethylene polymerizationpt
dc.subjecthomogeneous binary catalyst systempt
dc.subjectsynergistic effectpt
dc.subjectTi and Ni catalystspt
dc.titleSynthesis and properties of branched polyethylene/high-density polyethylene blends using a homogeneous binary catalyst system composed of early and late transition metal complexesen
dc.typeArtigo
dcterms.licensehttp://olabout.wiley.com/WileyCDA/Section/id-406071.html
dcterms.rightsHolderWiley-Blackwell

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