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Copolymerization of ethene with 1‐hexene or 1‐hexadecene over ethylene, dimethylsilylene and 1,4‐butanediylsilylene bridged bis(indenyl) and bis(tetrahydroindenyl)zirconium dichlorides
Author(s) -
Lehmus Petri,
Härkki Outi,
Leino Reko,
Luttikhedde Hendrik J. G.,
Näsman Jan H.,
Seppälä Jukka V.
Publication year - 1998
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/(sici)1521-3935(19980901)199:9<1965::aid-macp1965>3.0.co;2-x
Subject(s) - comonomer , copolymer , ethylene , polymer chemistry , 1 hexene , hexene , methylaluminoxane , silylene , metallocene , catalysis , chemistry , zirconium , polymerization , materials science , organic chemistry , silicon , polymer
Ethene was copolymerized with 1‐hexene and 1‐hexadecene over five different homogeneous methylaluminoxane (MAO) activated racemic ansa ‐metallocene catalysts in order to study both the influence of the ligand (indenyl and tetrahydroindenyl) and the influence of the interannular bridge (ethylene, dimethylsilylene and 1,4‐butanediylsilylene) on the copolymerization behaviour. Hydrogenation of the indenyl ligands was found to decrease comonomer content and molar mass of the copolymers. A similar tendency was observed for the ethylene bridge compared to the silylene bridges. The reasons for this behaviour are discussed and related to structural differences of the catalyst precursors. In addition a segregation fractionation technique was applied to study the chemical composition distribution (CCD) of the produced copolymers. Batchwise feed of comonomer resulted in a broad CCD. More homogeneous copolymers could be produced using partly continuous feed of comonomer.