Results 181 to 190 of about 5,101 (224)
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An Electrochemical Study of the Ziegler - Natta Catalyst
Analytical Letters, 1982Abstract An anodic voltanmetric study was made of the Ziegler-Natta catalyst in tetrahydrofuran using a rotating platinum electrode. It was shown that these measurements could be used as an indication of the activity of the catalyst. It was also observed that the catalyst and the cocatalyst (diethyl aluminum chloride) formed an electrochemically ...
Thomas C. Franklin, Masahiro Ohta
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Polymerization of phenylacetylene on Ziegler-Natta catalysts
Bulletin of the Academy of Sciences of the USSR Division of Chemical Science, 19681. The kinetics of the polymerization of phenylacetylene on catalysts (α, δ-TiCl3)-(C3H5)3Al in heptane and benzene medium was studied by a dilatometric method. 2. The influence of the concentration of the components of the catalytic system on the rate of polymerization of phenylacetylene was investigated, and the observed constants ...
G. I. Bantsyrev +2 more
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Prepolymerization of ethylene with a Ziegler–Natta catalyst
Journal of Applied Polymer Science, 2007AbstractThe slurry prepolymerization of ethylene using TiCl4/MgCl2 as a catalyst was investigated. A 23‐factorial experimental design method was employed to study the effects of the temperature, hydrogen, and active cocatalyst‐to‐catalyst molar ratio (Al/Ti) on the catalyst activity, prepolymer melt flow index, and powder bulk density.
Ahmad Mirzaei +2 more
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Amalgamation of ziegler‐natta and metallocene catalysts
Macromolecular Symposia, 1997AbstractThe MgCl2 supported half titanocenes and Ti(4, 4, 4‐trifluoro‐1‐phenyl‐1, 3‐butanedionato)2Cl2 catalysts were synthesized and applied to propene polymerization. Without supporting on MgCl2, those complexes displayed almost no activity even using methylaluminoxane (MAO) as cocatalyst.
K. Soga +4 more
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Advances in Ziegler-Natta catalysts for polypropylene
Kinetics and Catalysis, 2006The most advanced catalysts, based on MgCl2-supported TiCl4 and electron donors, are able to provide polypropylenes with an isotacticity higher than 99%. This, together with the continuous progress made in understanding and exploiting the role of electron donors in controlling polymer MW and MWD, has led to polypropylene products having an ...
A. Ferraro +4 more
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Stereochemical Control in Ziegler-Natta Catalysts
1987The remarkably high level of stereoselectivity associated with magnesium chloride-based catalysts is realized only in the presence of a selectivity control agent (SCA), frequently an aromatic ester.1 The usual effect of the SCA is to reduce activity while significantly enhancing stereoselectivity.2 Fortunately, the reduction in productivity (65%) is ...
S. E. Wilson, W. L. Callender, R. C. Job
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Ziegler-Natta catalysts for olefin polymerizations
Progress in Polymer Science, 1997Abstract This article reviews the recent developments of Ziegler-Natta and metallocene catalysts for olefin polymerizations. The roles of magnesium dichloride and electron donors on the activity and stereospecificity of Ziegler-Natta catalysts, as well as the roles of methylalumoxane and ligands on the activation and performance of metallocene ...
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Characterization of a model Ziegler–Natta catalyst for ethylene polymerization
The Journal of Chemical Physics, 2002Based on the work of the Somorjai group [Magni and Somorjai, Catal. Lett. 35, 205 (1995)] we have prepared a thin well ordered MgCl2(001) film by MgCl2 evaporation from a Knudsen cell. This film does not absorb TiCl4 at room temperature if it is not activated by increasing the defect density via electron or ion bombardment.
Schmidt, J. +3 more
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Electronic effects in homogeneous indenylzirconium Ziegler-Natta catalysts
Organometallics, 1990A series of new bis(indenyl)zirconium(IV) complexes of the general formula ({eta}{sup 5}-4,7-X{sub 2}C{sub 9}H{sub 5}){sub 2}ZrCl{sub 2} and ({eta}{sup 5}-4,7-X{sub 2}C{sub 9}H{sub 5}){sub 2}Zr(CH{sub 2}H{sub 5}){sub 2} (where X = H, CH{sub 3}, OCH{sub 3}, and F) were synthesized in order to investigate the electronic effects of substitutents on the ...
PICCOLROVAZZI, N +4 more
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Polymerization of vinylcyclohexane with ziegler–natta catalyst
Journal of Polymer Science Part A: Polymer Chemistry, 1992AbstractPolymerization of vinylcyclohexane (VCHA) with TiCl3–aluminum alkyl catalysts was investigated. The polymerization rate of VCHA was low due to the branch at the position adjacent to the reacting double bond. The effects of aluminum alkyl on the polymerization and monomer‐isomerization were observed; the polymer yield decreased in the following ...
Kiyoshi Endo, Takayuki Otsu
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