Sodium hydride/trialkylaluminum complexes for the controlled anionic polymerization of styrene at high temperature

Stéphane Carlotti (1, 2) , Stéphane Ménoret (1) , Philippe Desbois (3) , Norbert Nissner (3) , Volker Warzelhan (3) , Alain Deffieux (1)

1 LCPO - Laboratoire de Chimie des polymères organiques
2 Team 1 LCPO : Polymerization Catalyses & Engineering
3 BASF - Polymer Laboratory

A new generation of anionic initiators (butyl-lithium 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 degrees 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.

Mots clés: retarded anionic polymerization; high temperature; polystyrene; sodium hydride

Domaines: Polymères

Stéphane Carlotti, Stéphane Ménoret, Philippe Desbois, Norbert Nissner, Volker Warzelhan, et al.. Sodium hydride/trialkylaluminum complexes for the controlled anionic polymerization of styrene at high temperature. Macromolecular Rapid Communications, 2006, 27 (12), pp.905-909. ⟨10.1002/marc.200600176⟩. ⟨hal-00342078⟩