Synthesis of Polyamide-benzoxazoles

Abstract

The solution polycondensation of 2, 4-diaminophenol dihydrochloride in an inert atmosphere with adipic acid, suberic acid, azelaic acid, sebacic acid, terephthalic acid, isophthalic acid, diphenic acid and pyridine-2, 4-dicarboxylic acid in polyphosphoric acid was found to give the corresponding polyamide-benzoxazoles in 4286% yield.
Their preparations and physical properties, such as thermal stability, solubility and viscosity, were determined.
These results suggested that the polyamide-benzoxazoles with all aromatic units showed outstanding heat stability, however, the polyamide-benzoxazoles had lower thermal stability than the polyamide-benzimidazoles, although their solubilities in solvents such as dimethyl sulfoxide, N, N-dimethylformamide, m-cresol and formic acid were the same.