Calcium–Lithium Systems as Innovative Bimetallic Initiators for the Anionic Polymerization of Butadiene: Toward Control and High 1,4-trans Microstructure
Thomas La Porta, Renaud Perrin, Mélanie Ray, Benoît Gadenne, Charlotte Dire, Stéphane Carlotti
Abstract
Polybutadiene architecture and microstructure are key parameters for the mechanical and viscoelastic properties of rubber materials. The versatility of anionic polymerization can supply a variety of polymers with different architectures and chain end functionalization, but few reports show the ability to increase 1,4-trans units of polybutadiene. Herein, we report the first controlled anionic polymerization of butadiene using an innovative bimetallic Ca:Li initiator. [(THF) 2 Ca(HMDS) 2 ]:[ n -BuLi] in situ prepared allowed the polymerization of butadiene in apolar medium, with the control of molar masses, a low dispersity (below 1.2), a living character, and the modulation of 1,4-trans units between 55 and 80% while maintaining a low vinyl content (below 10%). The influence of the [Ca]/[Li] ratio on the polybutadiene microstructure, kinetics, control, and living character of the polymerization are investigated and discussed.