Living anionic polymerization of 2-vinyidibenzothiophene:: Homopolymer and block copolymers with styrene

2-Vinyldibenzothiophene (2VDBT) was synthesized from the 2-bromodibenzo-thiopbene previously prepared. Then, anionic polymerization of 2-vinyldibenzothiophene and its copolymerization with styrene were carried out under nitrogen atmosphere in benzene at 30 degrees C using n-butyllithium as initiator. The anionic polymerization of 2VDBT showed a living character, since it fulfilled the criterion for the linearity of the plot of ln([M]())/[M]) with time, together with the requirement that M-n must vary linearly with conversion. Narrow molecular weight distribution (M-w/M-n < 1.1) and predictable molecular weight were obtained for homopolymerization of poly(2VDBT), taking into account the overestimation of experimental M-n(GPC) due to the possible higher hydrodynamic volume arising from the bulky dibenzothiophenyl group of poly(2VDBT) in comparison to the phenyl group of polystyrene. Also, sequential copolymerization by addition of 2VDBT and styrene yielded block copolymers showing narrow polydispersity (M-w/M-n < 1.08). The anionic polymerization of mixtures of 2VDBT and styrene was carried out and their relative reactivity ratios were estimated by applying both the Kelen-Tudos and the Joshi-Joshi methods. The former yielded values of r(2VDBT) = 1.11 +/- 0.77 and r(st) = 0.49 +/- 0.10, whereas the latter gave the values r(2VDBT) = 1.05 +/- 0.05 and r(st) = 0.50 +/- 0.10 for the reactivity ratios. (c) 2006 Wiley Periodicals, Inc.