Polyhydrazides based upon aromatic dihydrazines

The paper deals with the study of the polycondensation reaction between two aromatic dihydrazines (bis(4-hydrazinophenyl)methane (BHPM) and bis(4-hydrazinophenyl)sulfone) and two diacyl chlorides (1,3-bis(4-chloroformyl-phenyl) parabanic acid and isophthaloyl chloride). The possibility of the side reaction during the polymer synthesis was studied by using model reactions and analysis by high performance liquid chromatography. The benzoyl phenyl hydrazine hydrochloride complex was obtained as a relatively stable intermediate. By using a weak hydrogen chloride acceptor like pyridine, a controlled release of hydrogen chloride from this complex was performed and the secondary reactions were considerably reduced. Soluble polymers were so obtained even in the case of the reaction between BHPM and isophthaloyl chloride, which usually produces only insoluble products. The thermal properties of the polymers were studied by thermogravimetric analyses and differential scanning calorimetry methods.