Living anionic polymerization of 2‐vinyldibenzothiophene: Homopolymer and block copolymers with styrene

Abstract 2‐Vinyldibenzothiophene (2VDBT) was synthesized from the 2‐bromodibenzothiophene previously prepared. Then, anionic polymerization of 2‐vinyldibenzothiophene and its copolymerization with styrene were carried out under nitrogen atmosphere in benzene at 30 °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]0[M]) with time, together with the requirement that Mn must vary linearly with conversion. Narrow molecular weight distribution (MwMn < 1.1) and predictable molecular weight were obtained for homopolymerization of poly(2VDBT), taking into account the overestimation of experimental Mn(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 (MwMn <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 Kélen–Tüdös and the Joshi–Joshi methods. The former yielded values of r2VDBT = 1.11 ± 0.77 and rSt = 0.49 ± 0.10, whereas the latter gave the values r2VDBT = 1.05 ± 0.05 and rSt = 0.50 ± 0.10 for the reactivity ratios.