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Comonomer‐Induced Stereo‐Selectivity Enhancement in a C 2 ‐Symmetric Metallocene‐Catalyzed Propylene Polymerization
Author(s) -
Ma Lin,
Dong JinYong
Publication year - 2015
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.201400736
Subject(s) - comonomer , metallocene , selectivity , polymerization , catalysis , materials science , polymer chemistry , post metallocene catalyst , chemistry , organic chemistry , composite material , polymer
Propylene polymerization is carried out with a C 2 ‐symmetric metallocene catalyst of rac ‐Et(Ind) 2 ZrCl 2 /MAO at 40 °C in the presence of a cyclo‐triene of trans,trans,cis‐ 1,5,9‐cyclododecatriene (( E , E , Z )‐CDT). Comonomer incorporations are rather low (<0.10 mol%). However, it is shown for the first time that the comonomer causes a noticeable increase in polypropylene isotacticity (>7% in [ mmmm ]). ( E , E , Z )‐CDT is speculated to coordinate to the metal center forming comonomer‐complexed active sites in charge of the entire polymerization reaction with decreased activity however increased propylene enantiomorphic selectivity.