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Copolymerisation properties of siloxy‐substituted bis(indenyl)zirconocene catalysts: modified rheological behaviour
Author(s) -
Seppälä Jukka,
Löfgren Barbro,
Lehmus Petri,
Malmberg Anneli
Publication year - 2001
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/1521-3900(200108)173:1<227::aid-masy227>3.0.co;2-q
Subject(s) - branching (polymer chemistry) , rheology , catalysis , polyethylene , zirconium , ethylene , polymer , polymer chemistry , polymerization , selectivity , chemistry , materials science , organic chemistry , composite material
The combination of the copolymerisation ability and vinyl end group selectivity of siloxy substitution of ethylene‐bridged bis(indenyl)zirconium dichlorides suggest these catalyst as potential ones for the production of polyethylene containing small amounts of long chain branching. The role of the polymerisation conditions with these highly active catalysts can clearly be seen. Furthermore low contents of multiple branches may occur, even though the probability of attaching several macromonomers into one chain is low. The effect on melt rheological behaviour depends on both the amount of long chain branching and the length of the branch. Moreover the position of the siloxy group is very important. Polymers synthesized with catalysts, where the siloxy group is in position 1, give peculiar rheological behaviour resembling cross‐linked networks although the polymers are completely soluble.