Synthesis and characterization of novel polyurethanes based on 4,4′-[1,4-phenylenedi-diazene-2,1-diyl]bis(2-carboxyphenol) and 4,4′-[1,4-phenylenedi-diazene-2,1-diyl]bis(2-chlorophenol) hard segments

Eight novel polyurethanes (PUs) based on 4,4′-[1,4-phenylenedi-diazene-2,1-diyl]bis(2-carboxyphenol) and 4,4′-[1,4-phenylenedi-diazene-2,1-diyl]bis(2-chloro- phenol) as hard segments with four diisocyanates viz., 4,4′-diphenyl-methane diisocyanate, toluene 2,4-diisocyanate, isophorone diisocyanate and hexamethylene diisocyanate were prepared. Structural and thermal characterization of the segmented PUs were determined by FT-IR, UV spectrophotometry, fluoroscence spectroscopy, 1H NMR, 13C NMR spectroscopy and DTA/TGA analysis. All the PUs contain domains of semi-crystalline and amorphous structures, as indicated by X-ray diffraction. PUs were soluble in polar aprotic solvents like N-methyl-2-pyrrolidone (NMP), dimethyl formamide (DMF) and dimethylsulfoxide (DMSO).