Living Anionic Polymerization of Styrene Derivatives Containing Triphenylamine Moieties through Introduction of Protecting Group

We carried out the anionic polymerization of styrene derivatives containing the triphenylamine moieties, 4,4′-vinylphenyltriphenylamine (A) and 4,4′-vinylphenyl-N,N-bis(4-tert-butylphenyl)benzenamine (B), with a variety of initiators in tetrahydrofuran (THF) at −78 °C. The anionic polymerization of A was performed with sec-butyllithium, sec-butyllithium with additives, and (diphenylmethyl)potassium in THF at −78 °C. In all cases, an intermolecular side reaction took place between the polymer chains during polymerization. In contrast, the anionic polymerization of B was carried out successfully with sec-butyllithium and potassium naphthalenide in THF at −78 °C for 0.5 h without any observed intermolecular side reaction. Well-defined poly(B)s with predictable molecular weights and narrow molecular weight distributions (Mw/Mn = 1.05−1.11) were obtained. The sequential block copolymerization of B with styrene and 2-vinylpyridine was attempted subsequently, and the well-defined block copolymers, polystyrene-b-poly(B) and poly(B)-b-poly(2-vinylpyridine), were synthesized quantitatively. The solubilities as well as the thermal and optical properties of the resulting poly(B) were investigated.