INFLUENCE OF EXTERNAL ALKOXYSILANE DONORS ON THE STEREOSPECIFICITY AND KINETICS OF PROPYLENE POLYMERIZATION
Rubrics: 2. CHEMICAL TECHNOLOGY
Authors:
1.
Kazan National Research Technological University
2.
Samara State Technical University
3.
Kazanskiy nacional'nyy issledovatel'skiy tehnologicheskiy universitet
4.
KNITU
Type:
Article
Pages:
from 64
to 72
Status:
Published
Received:
17.02.2026
Accepted:
13.03.2026
Published:
05.04.2026
Language:
Russian
Keywords:
POLYPROPYLENE, ZIEGLER-NATTA CATALYSTS, EXTERNAL DONORS, ALKOXYSILANES, STEREOSPECIFICITY, ISOTACTICITY, POLYMERIZATION KINETICS
Abstract:
Polypropylene is one of the most widely produced thermoplastic polymers and holds a leading position among polyolefins due to its combination of low density, high chemical resistance, satisfactory mechanical properties, and processability. The performance properties of polypropylene are largely determined by its microstructure, primarily its degree of stereoregularity and molecular weight characteristics. These parameters are formed directly during the polymerization stage and depend on the nature of the catalytic system and process conditions. External electron donor compounds are among the key factors determining the performance of modern heterogeneous Ziegler-Natta catalysts in industrial propylene polymerization. Alkoxysilane donors are widely used in commercial polypropylene production technologies to regulate isotacticity, molecular weight characteristics, and overall process productivity. This work presents an analysis of the influence of the structure and concentration of external alkoxysilane donors on the stereospecificity of active centers and the kinetic parameters of propylene polymerization in the presence of MgCl₂-supported titanium catalysts. It is shown that variation of the substituents at the silicon atom, as well as the number and type of alkoxy groups, enables purposeful control of the distribution of active centers with respect to stereospecificity, chain propagation rate, and the extent of center deactivation. It has been established that changes in donor concentration lead to systematic variations in catalytic activity and polymer isotacticity, which directly affect crystallinity, melting temperature, mechanical properties, and processability of polypropylene. A generalization of the available literature data makes it possible to identify structural parameters of alkoxysilanes that provide an optimal balance between high catalytic activity and enhanced stereoregularity of the polymer. The conclusions obtained are of practical importance for the rational design and optimization of catalytic systems and for the development of industrial polypropylene production processes with tailored material properties.
Polypropylene is one of the most widely produced thermoplastic polymers and holds a leading position among polyolefins due to its combination of low density, high chemical resistance, satisfactory mechanical properties, and processability. The performance properties of polypropylene are largely determined by its microstructure, primarily its degree of stereoregularity and molecular weight characteristics. These parameters are formed directly during the polymerization stage and depend on the nature of the catalytic system and process conditions. External electron donor compounds are among the key factors determining the performance of modern heterogeneous Ziegler-Natta catalysts in industrial propylene polymerization. Alkoxysilane donors are widely used in commercial polypropylene production technologies to regulate isotacticity, molecular weight characteristics, and overall process productivity. This work presents an analysis of the influence of the structure and concentration of external alkoxysilane donors on the stereospecificity of active centers and the kinetic parameters of propylene polymerization in the presence of MgCl₂-supported titanium catalysts. It is shown that variation of the substituents at the silicon atom, as well as the number and type of alkoxy groups, enables purposeful control of the distribution of active centers with respect to stereospecificity, chain propagation rate, and the extent of center deactivation. It has been established that changes in donor concentration lead to systematic variations in catalytic activity and polymer isotacticity, which directly affect crystallinity, melting temperature, mechanical properties, and processability of polypropylene. A generalization of the available literature data makes it possible to identify structural parameters of alkoxysilanes that provide an optimal balance between high catalytic activity and enhanced stereoregularity of the polymer. The conclusions obtained are of practical importance for the rational design and optimization of catalytic systems and for the development of industrial polypropylene production processes with tailored material properties.
Keywords:
POLYPROPYLENE, ZIEGLER-NATTA CATALYSTS, EXTERNAL DONORS, ALKOXYSILANES, STEREOSPECIFICITY, ISOTACTICITY, POLYMERIZATION KINETICS
POLYPROPYLENE, ZIEGLER-NATTA CATALYSTS, EXTERNAL DONORS, ALKOXYSILANES, STEREOSPECIFICITY, ISOTACTICITY, POLYMERIZATION KINETICS
