Synthesis and characterization of MDI and functionalized polystyrene based poly(urethane-urea-amide)

This article describes the synthesis of 4,4′-methylenediphenyl diisocyanate (MDI) based polyurethane-ureas-amide using diamine-diamide chain extenders and dihydroxy polystyrene (PSt) having a weight average molecular weight of 2000 g/mol. The weight average molecular weight of the soft segment is varied from 2000 to 10,000 g/mol using MDI as a chain extender and thereby changing the hard segment content from 30 to 17 wt% in the copolymer. The inherent viscosity of the polymer is found to be in the range of 1.6–3.4 dL/g is suggesting that the polymer is of high molecular weight. FT-IR results conclude that the urea groups form monodentate assemblies. DSC data show the peaks for Tg of soft and Tm of hard segments. Depending on the amide concentration, the melting temperature of the polymer varies from 189 to 249 °C. Also, at high concentration of the hard segment, the cooling curve shows crystallization exotherm peak. The entire series of polymer shows single stage decomposition temperature centered around 400 °C shown by the TGA measurement. The solubility of the polymer in chloroform and swelling ratio is depending on the concentration of the hard segment. The studied polymer shows excellent solvent resistivity.