Sodium Hydride/Trialkylaluminum Complexes for the Controlled Anionic Polymerization of Styrene at High Temperature

• Published in: Macromolecular rapid communications. Vol. 27; no. 12; pp. 905 - 909
• Main Authors: Carlotti, Stéphane, Menoret, Stephane, Desbois, Philippe, Nissner, Norbert, Warzelhan, Volker, Deffieux, Alain
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 24.06.2006; WILEY‐VCH Verlag; Wiley; Wiley-VCH Verlag
• Subjects: anionic polymerization; Applied sciences; Chemical Sciences; Exact sciences and technology; high temperature; Organic polymers; Physical Sciences; Physicochemistry of polymers; Polymer Science; Polymerization; Polymers; polystyrene; Preparation, kinetics, thermodynamics, mechanism and catalysts; retarded; Science & Technology; sodium hydride; sodium hydride; polystyrene; retarded; REACTIVITY; LEWIS-ACIDS; anionic polymerization; high temperature; HYDRIDE; Bulk polymerization; Priming activity; Living polymer; High temperature; polystyrène; Experimental study; Solution polymerization; high température; Anionic catalyst; Reaction mechanism; Sodium hydride; Anionic polymerization; Styrene polymer; Aluminium Organic compounds; retarded anionic polymerization
• ISSN: 1022-1336; 1521-3927
• DOI: 10.1002/marc.200600176

A new generation of anionic initiators (butyllithium free), based on trialkylaluminum and a readily available alkali metal hydride, has been developed for the control of styrene polymerization at high temperature. Triisobutylaluminum and sodium hydride form heterocomplexes that are efficient for the initiation of styrene polymerization at 100 °C in toluene or in bulk. To be active under such conditions, these systems require the presence of an excess of metal hydride with respect to AlR3 ([Al]/[Na] < 1). PS chains are specifically initiated by the hydrides coming from NaH, and molar masses are controlled in the range 0.8 < [Al]/[Na] < 1. Fast exchange between dormant 1:1 and active 1:2 complexes (Al:Na), and ligand rearrangements within the 1:2 complex, can explain the observed results. Initiation of styrene with i‐Bu3Al/NaH systems.