Lithium Naphthalenides in Non-Polar or in Low Polarity Media: Some Insights Regarding their Use as Initiators in Anionic Polymerizations

M.D. NINAGO; M.L. SENA MARANI; V.A. GONZÁLEZ; A.J. SATTI; C. SARMORIA; M.A. VILLAR; E.M. VALLÉS; A.E. CIOLINO

POLYMER BULLETIN

SPRINGER

Lugar: Berlin; Año: 2017 vol. 74 p. 327 - 333

0170-0839

The synthesis of bidirectional anionic initiators by the reaction between metallic lithium (Li) and naphthalene (Naph), under mild conditions, in non-polar (benzene) or low-polarity media (benzene/THF mixtures) is reported. The efficiency of these initiators to provide macromolecules with well-defined structures was demonstrated. Model linear homopolymers from styrene (S) or hexamethyl(ciclotrisiloxane) (D3) monomers were synthesized using classical anionic polymerization (high-vacuum techniques). The model polymers obtained were analyzed using the conventional analytical techniques, and showed narrow molar mass distributions, a broad range of molar masses (from 3000 to 1,000,000 g/mol) and polydispersity indexes (Mw/Mn) lower than 1.1. High molar mass polymers were obtained using pure benzene as solvent, whereas lower molar masses were obtained in benzene/THF mixtures in which the concentration of THF was lower than 10 % v/v. The ratio [Li]/[Naph] and the nature of the reaction medium are the experimental parameters to be controlled to obtain the desired lithium naphthalenides.