Effect of alkylaluminum structure on Ziegler-Natta catalyst systems based on neodymium for producing high-cis polybutadiene

Summary In this work, a laboratory scale process for producing polybutadiene with high content of cis -1,4 repeating units was studied. A Ziegler-Natta catalyst system constituted of neodymium versatate (catalyst), an alkylaluminum compound (alkylating agent and cocatalyst) and tert-butyl chloride (...

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Published in:Polymer bulletin (Berlin, Germany) Germany), 2009, Vol.62 (1), p.1-10
Main Authors: Rocha, Tereza C. J., Coutinho, Fernanda M. B., Soares, Bluma G.
Format: Article
Language:English
Subjects:
Alkylaluminium
Alkylation
Aluminum
Aluminum hydrides
Applied sciences
Characterization and Evaluation of Materials
Chemistry
Chemistry and Materials Science
Complex Fluids and Microfluidics
Cyclohexane
Exact sciences and technology
Hexanes
Neodymium
Organic Chemistry
Organic polymers
Physical Chemistry
Physicochemistry of polymers
Polybutadiene
Polymer Sciences
Polymerization
Polymers
Preparation, kinetics, thermodynamics, mechanism and catalysts
Soft and Granular Matter
Ziegler-Natta catalysts
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Summary:Summary In this work, a laboratory scale process for producing polybutadiene with high content of cis -1,4 repeating units was studied. A Ziegler-Natta catalyst system constituted of neodymium versatate (catalyst), an alkylaluminum compound (alkylating agent and cocatalyst) and tert-butyl chloride (chlorinating agent) was used. The solvent employed was a mixture of hexane and cyclohexane (80/20 v/v). The objective of this work was to evaluate the effect of alkylaluminum structure and the influence of Al/Nd (5 to 15) molar ratio of long chain alkylaluminium compound (tri(n-hexyl)aluminum) on catalyst activity and polybutadiene characteristics. The alkylaluminum compounds employed in this study were tri(i-butyl)aluminum, tri(n-hexyl)aluminum, tri(n-octyl)aluminum and di(i-butyl)aluminum hydride. The polybutadienes molar masses obtained were strongly influenced by the alkylaluminum structure. Polymers with the highest molar masses were obtained when tri(i-butyl)aluminum, tri(n-hexyl)aluminum and tri(n-octyl)aluminum were employed. However, polymers with the highest contents of cis -1,4 units and the lowest molar masses were produced when di(i-butyl)aluminum hydride was employed.
ISSN:0170-0839
1436-2449
DOI:10.1007/s00289-008-1006-7