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Morphological influences in the gas phase polymerization of ethylene by silica supported chromium oxide catalysts
Author(s) -
Webb Steven W.,
Weist E. L.,
Chiovetta M. G.,
Laurence R. L.,
Conner W. C.
Publication year - 1991
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.5450690309
Subject(s) - polymerization , materials science , catalysis , polymer , chain growth polymerization , chemical engineering , coordination polymerization , monomer , polymer chemistry , chemistry , solution polymerization , organic chemistry , radical polymerization , composite material , engineering
Abstract Dramatic changes occur during the initial stages of olefin polymerization over heterogenous catalysts. As polymer accumulates, the catalyst fragments and the void space within the growing particle becomes filled with polymer. The changing monomer transport rate to the active sites, dissipation of heat and stress with the particle, and eventually, dispersion of catalyst fragments within the growing particle can control the polymerization. We focus on the changes in, and influence of, polymer, catalyst and void morphology during the nascent polymerization for silica supported chromium oxide catalysts. We find that the course of the polymerization depends on the initial stages yet is seldom considered in polymerization models. We review several years of morphological characterization that identify the important physical phenomena which occur during nascent heterogeneous olefin polymerization.