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Long Chain Branched Polypropene Prepared by Means of Propene Copolymerization with 1,7‐Octadiene Using MAO‐Activated rac ‐Me 2 Si(2‐Me‐4‐Phenyl‐Ind) 2 ZrCl 2
Author(s) -
Walter Philipp,
Trinkle Stefan,
Lilge Dieter,
Friedrich Christian,
Mülhaupt Rolf
Publication year - 2001
Publication title -
macromolecular materials and engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.913
H-Index - 96
eISSN - 1439-2054
pISSN - 1438-7492
DOI - 10.1002/1439-2054(20010501)286:5<309::aid-mame309>3.0.co;2-f
Subject(s) - comonomer , propene , tacticity , copolymer , materials science , metallocene , polymer chemistry , polymerization , molecular mass , rheology , shear (geology) , catalysis , chemical engineering , polymer , composite material , chemistry , organic chemistry , engineering , enzyme
Small amounts of 1,7‐octadiene (OD) comonomer, ranging from 0.5–5.0 mol‐%, were added during propene polymerization, catalyzed with methylalumoxane (MAO) activated rac ‐Me 2 Si(2‐Me‐4‐phenyl‐Ind) 2 ZrCl 2 (MPI), in order to incorporate long chain branches and small amounts of high molecular mass polypropene (PP), thus improving melt processability of isotactic metallocene‐polypropene. As a function of the OD content the PP melting temperatures varied from 120 to 160°C. The presence of long chain branches was reflected by increased zero shear viscosities combined with pronounced shear thinning behavior in the case of propene/OD copolymers with molecular mass distribution of M̄ w / M̄ n < 4. Rheological measurements clearly revealed crosslinking occurring at high OD content. OD addition impaired catalyst activities. However, in the presence of trace amounts of ethene, catalyst activities increased significantly even in the presence of high OD content.