منابع مشابه
Quadrupolar nutation NMR to discriminate central and satellite transitions: Spectral assignments for a Ziegler-Natta catalyst.
In this contribution we used solid state 35Cl (I=3/2) quadrupolar NMR to study a MgCl2/2,2-dimethyl-1,3-dimethoxypropane (DMDOMe) adduct that serves as a model system for Ziegler-Natta catalysis. Employing large Radio-Frequency (RF) field strengths we observe three spectral features with strongly varying line widths. The assignment of the spectra is complicated because of the large difference i...
متن کاملIn situ stabilization of polypropylene by lignin using a Ziegler-Natta catalyst
A fourth-generation Ziegler-Natta catalyst was prepared to synthesize polypropylene (PP), which was stabilized by in situpolymerization employing lignin as antioxidant. The antioxidant properties of lignin were compared with those of the commercial antioxidant Irganox 1010. The presence of lignin in the reaction medium slightly decreased the catalytic activity of the reaction. The isotacticity ...
متن کاملZiegler-Natta Catalysis: Structural Variations and Tacticity Control
Models for the likely active catalysts in homogeneous Ziegler-Natta systems have been studied using ab initio quantum chemical methods. We investigated the geometries of the isoelectronic model complexes, X2M-R where X = C1 or Cp = (q5-CsHs); where M = Sc and Ti+ (and also Ti); and where R = H, CH3, or SiH3. The general trend is that the M = Sc compounds strongly prefer a planar configuration, ...
متن کاملin situ stabilization of polypropylene by lignin using a ziegler-natta catalyst
a fourth-generation ziegler-natta catalyst was prepared to synthesize polypropylene (pp), which was stabilized by in situ polymerization employing lignin as antioxidant. the antioxidant properties of lignin were compared with those of the commercial antioxidant irganox 1010. the presence of lignin in the reaction medium slightly decreased the catalytic activity of the reaction. the isotacticity...
متن کاملPrecise Active Site Analysis for TiCl3/MgCl2 Ziegler-Natta Model Catalyst Based on Fractionation and Statistical Methods
In heterogeneous Ziegler-Natta catalysts for olefin polymerization, isolation of a single type of active sites is a kind of ambition, which would solve long-standing questions on the relationship between active site and polymer structures. In this paper, polypropylene produced by TiCl3/MgCl2 model catalysts with minimum Ti heterogeneity was analyzed by combined solvent fractionation and the two...
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ژورنال
عنوان ژورنال: Journal of Polymer Science Part A: Polymer Chemistry
سال: 2012
ISSN: 0887-624X
DOI: 10.1002/pola.26307