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XPS and EXAFS characterization of Ziegler–Natta catalyst systems
Author(s) -
da Silva Filho Adilson Arli,
Martins Alves Maria do Carmo,
dos Santos João Henrique Zimnoch
Publication year - 2008
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.28310
Subject(s) - extended x ray absorption fine structure , catalysis , x ray photoelectron spectroscopy , binding energy , polymerization , natta , absorption (acoustics) , x ray absorption fine structure , materials science , chemistry , polymer chemistry , spectroscopy , crystallography , absorption spectroscopy , polymer , organic chemistry , physics , nuclear magnetic resonance , quantum mechanics , composite material , nuclear physics
A series of Ziegler–Natta catalysts, with and without diisobutylphtalate as an internal donor, were modified with alkylaluminum (triethylaluminum or diethylaluminum chloride) and an external donor (diisopropyldimethoxysilane or methyltrimethoxysilane), in increasing complexity. The resulting catalysts were characterized by X‐ray photoelectron spectroscopy and extended X‐ray absorption fine structure analysis (EXAFS) and evaluated in propylene polymerization. According to EXAFS oscillation, systems bearing diisobutylphtalate as an internal donor displayed a well‐defined pattern, suggesting a more ordered structure around the Ti atom. EXAFS data treatment provided two TiCl distances: ∼ 1.96 and 2.5 Å. The former was shown to have a linear dependence on the Ti (2p 3/2 ) binding energy as the catalyst is modified with TEA or with external donors. Conversely, the longest distance is reduced as Ti (2p 3/2 ) binding energy increases with catalyst modification. Correlations involving the catalyst activity, Ti (2p 3/2 ) binding energy, and TiCl distances could be denoted. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008