Polycondensation In Polyphosphoric Acid Research Articles

Preparation of some new polybenzimidazoquinazolines

AbstractSeveral new types of polybenzimidazoquinazolines with a different recurring unit have been prepared by solution polycondensation in polyphosphoric acid followed by heating at elevated temperature under reduced pressure. The polymers thus obtained were light yellow to brown powdery materials hardly soluble in common organic solvents and soluble in concentrated sulfuric acid. The inherent viscosity of the polymers ranged from 0.1 to 0.58 and showed good thermal stability.

Poly‐1,3,4‐oxadiazoles. III. Alicyclic poly‐1,3,4‐oxadiazoles

AbstractSome alicyclic poly‐1,3,4‐oxadiazoles were prepared from cycloalkanedicarboxylic dihydrazides or from cycloalkanedicarboxylic acids and hydrazine sulfate by solution polycondensation in polyphosphoric acid. These polymers were characterized by high melting temperature. Their preparations and physical properties, such as solubility, crystallinity and thermal stability, are described.

Poly‐1, 3,4‐oxadiazoles. II. Aliphatic poly‐1,3,4‐oxadiazoles

AbstractAliphatic poly‐1,3,4‐oxadiazoles were prepared from aliphatic dicarboxylic dihydrazides or from dicarboxylic derivatives and hydrazine sulfate by solution polycondensation in polyphosphoric acid. Their preparation and physical properties, such as solubility, crystallinity, and thermal stability are described.