Investigations of the initial state polymerization of propylene with Ziegler-Natta catalysts in slurry

• Published in: Journal of applied polymer science Vol. 106; no. 1; pp. 354 - 359
• Main Authors: Heuvelsland, Albert, Wichmann, Silke, Schellenberg, Jürgen
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 05.10.2007; Wiley
• Subjects: adiabatic initial state polymerization; Applied sciences; catalysts; Exact sciences and technology; morphology; Organic polymers; Physicochemistry of polymers; poly(propylene); Polymerization; Preparation, kinetics, thermodynamics, mechanism and catalysts; Ziegler-Natta polymerization; Particle size; Ziegler Natta catalyst; Ziegler-Natta polymerization; Propylene polymer; poly(propylene); Complex catalyst polymerization; Experimental study; Supported catalyst; Titanium IV Chlorides; Heterogeneous polymerization; Structure processing relationship; Morphology; catalysts; Olefin polymer; adiabatic initial state polymerization; Aluminium Organic compounds; Kinetics; Catalyst activity
• ISSN: 0021-8995; 1097-4628
• DOI: 10.1002/app.26691

The initial state polymerization of propylene with Ziegler–Natta catalysts has been investigated and discussed at very low polymerization yields under adiabatic industrial prepolymerization conditions in diluted slurry regarding the effects of significant process parameters like monomer pressure, aluminum alkyl, and donor kind and concentration including the morphology of the catalyst/polymer particles formed. A sharp temperature increase in the first minutes of the initial state polymerization is followed by a temperature maximum and a slow decrease. With cocatalyst triethyl aluminum (TEAL), high prepolymerization yields were already achieved at a molar ratio TEAL/Ti of 3.0, remaining about constant until ratios of at least 300. The external donor dicyclopentyl dimethoxy silane leads to higher polymerization yields than the donor cyclohexyl dimethoxymethyl silane in the initial state polymerization too; however, both show a remarkable decreasing effect on polymerization yield above a specific molar ratio donor/Ti obviously correlated with the bulkiness of the alkyl groups. The particle size of the catalyst and the catalyst/prepolymer particles is increasing with polymerization yield until about 22 g PP/g Cat with particles almost perfectly spherical. The particle size distribution is rather broad at lower prepolymerization stages but unifying with lower polymerization rates at higher polymerization times. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007