Synthesis, characterization of novel dihydrazide containing polyurethanes based on N1,N2‐bis[(4‐hydroxyphenyl)methylene]ethanedihydrazide and various diisocyanates

Four novel types of polyurethanes (PUs) were prepared from N1,N2‐bis[(4‐hydroxyphenyl)methylene]ethanedihydrazide with two aromatic diisocyanates (4,4′‐diphenylmethane diisocyanate and tolylene 2,4‐diisocyanate) and two aliphatic diisocyanates (isophorone diisocyanate and hexamethylene diisocyanate). The chemical structure of both diol and PUs was confirmed by UV–vis, fluoroscence, FTIR, 1H NMR, and 13C NMR spectral data. DSC data show that PUs have multiple endotherm peak. X‐ray diffraction revealed that the PUs contained semicrystalline and amorphous regions that varied with the nature of the backbone structures. PUs were soluble in polar aprotic solvents.