Modified polyurethane with a covalent bond of dye molecule

In this article, we have successfully synthesized polyurethanes (PUs) with a covalent bond of dye molecule via a coupling agent of epichlorohydrin. The structure is proven by infrared (IR) spectra, which exhibits the absorption peak of dye molecule, as we expected. The dye-grafted polyurethanes were used to evaluate their inherent viscosity, mechanical, and thermal properties and, also, their dyeing behavior. For the inherent viscosity, the PUs with the grafting of the dye molecule demonstrate a lower value of viscosity than those without grafting of the dye molecule. The tensile strength is found to decrease with the grafting of the dye molecule due to the further separation of intermolecular distance of the grafted PUs. But the elongation at break is increased with the grafting of the dye molecule. In consideration of the thermal properties, PUs with the grafting of dye molecule exhibit higher Tgh than those without dye molecule. However, their Tgs and Tms of soft segment between dyed and undyed PU seem to be similar. For dye migration property, the PUs with the grafting of dye molecule are proven to be much lower thermal migration values (Mp%) than those of simple mixing of PU and dyestuff. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 245–253, 1999