Synthesis and Characterization of Poly{(benzo [1,2-d:4,5-d’]-bisthiazole-2,6-diyl)-1,4-cyclohexane}

Poly(benzobisthiazoles) with a flexible moiety are synthesized through the polycondensation process involving 2,5-diamino-1,4-benzenedithiol dihydrochloride and either cyclohexane-1,4-dicarboxylic acid or a combination of cyclohexane-1,4-dicarboxylic acid and terephthalic acid in polyphosphoric acid. The inherent viscosity of these poly(benzobisthiazoles) is measured at 30 °C in methanesulfonic acid, ranging from 1.0 to 1.39 dL/g. The polymer structures are confirmed through elemental analysis and spectroscopic comparison with appropriate model compounds. Thermal stability is assessed using thermogravimetric analysis (TGA) in a nitrogen atmosphere, and the glass transition temperature is determined via differential scanning calorimetry (DSC). Interestingly, the cyclohexyl poly(benzobisthiazole) exhibits lower stability at elevated temperatures compared to poly(p-phenylene bisthiazole) PBZT.