Synthesis and Characterization of Poly(arylene ether oxadiazole) Telechelics

Poly(arylene ether oxadiazole) telechelics with fluorine and hydroxyl end groups were synthesized by nucleophilic substitution polymerizations of 2,5-bis(4-fluorophenyl)-1,3,4-oxadiazole monomer with bishydroxy compounds containing -C(CH₃)₂, -C(CF₃)₂ and -SO₂- groups. Fluorotelechelics were obtained with about 3 repeating units (molecular weight about 2000 g·mol^-1) using a rather excess (100 mol-%) of bis(fluorophenyl) oxadiazole compound. On the other hand, hydroxytelechelics were synthesized with about 9 repeating units (molecular weight about 5000 g · mol^-1) using a small excess of bishydroxy compound (monomer molar ratio of 0.93). Sulfonated poly(arylene ether oxadiazole) hydroxytelechelics were also synthesized using sulfonated and unsulfonated bishydroxy compounds. All sulfonated hydroxytelechelics were partially water soluble, even when only 40 mol-% of sulfonated monomers was used. The number of repeating units of hydroxytelechelics increased up to 12 (molecular weight about 9000 g·mol^-1) using sulfonated monomers, probably because of the higher reactivity of sulfonated phenoxide. The molecular weights estimated by ¹H NMR were in agreement to the results obtained by SEC. The telechelics can be used as precursor for the synthesis of block copolymer.