Results 181 to 190 of about 4,997 (220)
Some of the next articles are maybe not open access.
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
openaire +1 more source
Synthesis of highly improved Ziegler‐Natta catalyst
Journal of Applied Polymer Science, 2009AbstractThe effects of media viscosity, mixing speed, and injection time on catalyst average particle size (APS), particle size distribution (PSD), and morphology in both conditions, with and without emulsifier, were investigated. Supports were prepared using a so‐called recrystallization method; then they were catalyzed under the same condition.
Majid Monji +3 more
openaire +1 more source
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 ...
openaire +1 more source
Ethylene polymerization with heterogeneous Ziegler-Natta catalysts
Polymer Bulletin, 1995TiCl4/SiO2, Ti(OC4H9)4/SiO2, MgCl2/TiCl4/SiO2 and MgCl2/Ti(OC4H9)4/SiO2 catalysts were prepared by treating silica gel with TiCl4, Ti(OC4H9)4, MgCl2/TiCl4 or MgCl2/Ti(OC4H9)4 in tetrahydrofuran (THF) solution. Ethylene polymerization was performed with these catalysts activated by common alkylaluminum compounds. The influence of magnesium dichloride on
Luiz Claudio de Santa Maria +3 more
openaire +1 more source
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
openaire +1 more source
Particle Control of Supported Ziegler-Natta Catalysts
1987A good catalyst for olefin polymerization should exhibit, among other characteristics, good morphological control of the resulting polymers, as well as high activity, control of the molecular weight and molecular weight distribution. Thus, in regard to the polymer morphology, particles with spherical shape, having an average diameter of about 500 u, no
A. Muñoz-Escalona +3 more
openaire +1 more source
Stereospecificity of Heterogeneous Ziegler-Natta Catalysts
1985The most prominent feature of heterogeneous Ziegler-Natta catalysts is their ability to produce isotactic olefin polymers exhibiting a combination of outstanding mechanical characteristics. This ability adds a new dimension to the description of the catalysts and the polymerization processes: the study of catalyst and polymerization parameters ...
openaire +1 more source
Atomically precise control in the design of low-nuclearity supported metal catalysts
Nature Reviews Materials, 2021Sharon J Mitchell +1 more
exaly