Silica supported metallocene/MAO-systems: comparison of the polypropylene growth during bulk phase polymerization with slurry phase experiments

Citation
J. Zechlin et al., Silica supported metallocene/MAO-systems: comparison of the polypropylene growth during bulk phase polymerization with slurry phase experiments, MACRO CH P, 201(5), 2000, pp. 597-603
Citations number
10
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Organic Chemistry/Polymer Science
Journal title
MACROMOLECULAR CHEMISTRY AND PHYSICS
ISSN journal
1022-1352 → ACNP
Volume
201
Issue
5
Year of publication
2000
Pages
597 - 603
Database
ISI
SICI code
1022-1352(20000324)201:5<597:SSMCOT>2.0.ZU;2-L
Abstract
A kinetic investigation of the bulk phase propylene polymerization with a s ilica supported metallocene/MAO system has been carried out. In spite of th e high monomer concentration and the resulting high activity it was possibl e to distinguish between different polymerization phases producing polymers with differing properties. Similar to prior experiments in slurry phase we noticed an induction period at lower reaction temperatures. Even at the dr astic conditions of polymerizing in the liquid monomer we were able to prov e strong initial diffusion limitation toward the monomer resulting from a p olymer layer formed during the first minutes. The use of an 1-octene prepol ymerized catalyst system leads to a markedly improved activity. This arises from a better monomer diffusion through the more amorphous poly(1-octene) layer compared to a highly isotactic polypropylene layer.