PBI are usually yellow to brown solid infusible up to 400 °C or higher. The solubility of PBI is controversial, because while most of the linear PBI are partly or entirely dissolved in strong protonic acids (for instance, sulfuric acid or methanesulfonic acid), contradictory observations of solubities have been recorded among weaker acids like formic acid, and in non-acidic media, such as the aprotic amide-type solvents and dimethyl sulfoxide.
Brandname: CELAZOLE ®