Polypyrazolinones from aromatic di(propynoic ester)s and aromatic dihydrazines

Novel polypyrazolinones with inherent viscosities ranging from 0.12 to 0.44 dL/g were prepared by the Michael-type nucleophilic addition-cyclization of various dihydrazines with 3,3′-(1,3- or 1,4-phenylene)bis(ethyl propynoate) (1,3- or 1,4-PEP) and 3,3′-(1,4-phenylene)bis(phenyl propynoate) (1,4-PPhP) in N-methylpyrrolidone (NMP) solution at 25–110°C. The polymers exhibited moderate thermal stability with initial weight loss in air about 200°C and in nitrogen about 300°C (TGA). No apparent T_g′s were observed by DSC analysis. The synthesis and characterization of the polypyrazolinones is discussed.