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Immobilization and Activation of a Single‐Site Chromium Catalyst for Ethylene Polymerization using MgCl 2 /AlR n (OEt) 3 − n Supports
Author(s) -
Severn John R.,
Kukalyekar Nileshkumar,
Rastogi Sanjay,
Chadwick John C.
Publication year - 2005
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.200400500
Subject(s) - methylaluminoxane , polyethylene , catalysis , polymerization , polymer , chromium , materials science , ethylene , polymer chemistry , analytical chemistry (journal) , crystallography , chemistry , metallocene , composite material , chromatography , organic chemistry , metallurgy
Summary: The effective immobilization and activation of a single‐site chromium catalyst for ethylene polymerization has been achieved using MgCl 2 /AlR n (OEt) 3 − n supports, without the use of methylaluminoxane (MAO) or a borate activator. High catalyst activity and a spherical polyethylene‐particle morphology is obtained. Furthermore, the single‐site characteristics of the catalyst are retained, the narrow molecular weight distribution of the polymers obtained are apparent from gel permeation chromatography (GPC) and confirmed by rheological characterization.Shear frequency dependence of the storage modulus of (♦ and ▴) polyethylene ( $\overline M _{\rm w} /\overline M _{\rm n}$ = 1.8–1.9) prepared using an immobilized Cr catalyst, compared to (▪) a reference polymer having $\overline M _{\rm w} /\overline M _{\rm n}$ = 4.1.