| 초록 |
Anionic polymerizations of a series of vinyl heterocycles such as 2-vinylbenzoxazole (1), 2-isopropenylbenzoxazole (2), 2-isopropenylbenzothiazole (3), 2-isopropenyl-N-methylbenzimidazole (4), 2-isopropenylthiazole (5), 2-vinylthiophene (6), and 2-vinylbenzothiophene (7) were carried out in THF at -78℃. The initiators included s-butyllithium, (1,1-diphenyl-3-methylpentyl)lithium, and (diphenylmethyl)potassium. The poly(1)s having broad molecular weight distributions (Mw/Mn >1.5) were produced in low yields. On the other hand, the polymerizations of 2-7 proceeded quantitatively within 2 h. The resulting poly(2-7) possessed the predicted molecular weights based on the molar ratios of monomers to initiators and the narrow molecular weight distributions (Mw/Mn < 1.1), indicating the living nature of the polymerizations. The stability of the propagating carbanions were confirmed by the postpolymerization. Novel block copolymers containing poly(vinyl heterocycle) segments were successfully synthesized by the sequential block copolymerization of 2-7 with comonomers.
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