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[摘要]：The anionic polymerization of styrene monomers para-substituted with pi-conjugated mono-, di-, and tri(9,9-dihexylfluorene) moieties, St-Fl, St-Fl(2), and St-Fl(3), was examined under the conditions either in THF at -78 degrees C or in tert-butylbenzene at 20 degrees C with sec-BuLi as an initiator. The polymerization of both St-F-1 and St-Fl(2) was found to proceed in a living manner to quantitatively afford the corresponding polymers with predictable molecular weights and narrow molecular weight distributions (M-w/M-n < 1.08). The anionic polymerization of St-Fl(3) was also indicative to proceed in a living manner but with an unpredictable molecular weight. Both AB and BA diblock copolymers with the well-defined and expected structures Could be Successfully prepared by the sequential addition of St-Fl or St-Fl(2) followed by styrene and vice versa. The block copolymerization results clearly indicate the living nature of the anionic polymerization of St-Fl and St-Fl(2) and the almost same anionic polymerization behaviors of both monomers as styrene in reactivities of monomer(s) and propagating chain-end anion(s). Solubilities, intrinsic viscosities, and glass transition temperatures of the poly(St-Fl) and poly(St-Fl(2)) herein prepared were measured. The optical absorption and luminescence spectra of the studied polymer films showed well-resolved vibronic structures and the peak maxima was progressively increased as the fluorene chain length increased. The luminescence spectra also showed reduced aggregation/excimer emission in comparison with that of parent polyfluorene. The present study Suggests that living anionic polymerization Could be employed to polymerize other styrene derivatives with pi-conjugated moieties in a controlled manner and such polymers may exhibit precisely defined physical properties. |
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