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Ethylene Polymerization by Metallocene Catalysts Supported over Siliceous Materials with Bimodal Pore Size Distribution
Author(s) -
Moreno Jovita,
van Grieken Rafael,
Carrero Alicia,
Paredes Beatriz
Publication year - 2011
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/masy.201000059
Subject(s) - materials science , polymerization , ethylene , metallocene , chemical engineering , mesoporous material , polymer , polymer chemistry , catalysis , calcination , catalyst support , copolymer , post metallocene catalyst , organic chemistry , composite material , chemistry , engineering
Summary: As known, the pore structure of the catalytic support plays a decisive role during the polymerization reactions determining intra‐particle mass and heat transport phenomena. In this work, several ethylene polymerizations have been carried out by using as catalytic support different mesostructured materials with unimodal and bimodal pore size distributions in order to evaluate the influence of this pore size distribution on the catalytic behavior. Calcined mesoporous materials were impregnated with the catalytic system MAO/(nBuCp) 2 ZrCl 2 and used for ethylene polymerization and ethylene/1‐hexene copolymerizations, at 70 °C and 5 bar of ethylene pressure. Polyethylenes obtained were characterized by GPC, DSC and Crystaf. Results indicate that porous structure of the support has a significant influence on polymerization activity and polymer properties. Despite the catalyst bimodal pore size distribution, only ethylene/1‐hexene copolymers presented a bimodal chemical composition distribution.