The synthesis of polymeric dyes based on waterborne polyurethane: a reaction kinetics study using UV absorption spectroscopy
Waterborne polyurethane (WPU) based polymeric dyes with anthraquinone chromophores were developed to realize coloring textiles and improve color fastness. The preparation of polymeric dyes through the reaction of 1,4-diamino-2,3-diphenoxyanthraquinone (DV26) and NCO-terminated prepolymer was monitored via UV absorption spectroscopy. With the progress of the reaction, the intensity of the absorption peak of the primary amine group at 586 nm decreased as a function of reaction time. Thus, the conversion of DV26 at different times and the reaction end point could be determined. The reaction mechanism corresponded to an autocatalytic reaction equation, basically. In addition, the results of performance tests showed that the polymeric dyes exhibited good emulsion stability, ultra-low migration percentages, good water resistance and excellent thermal stability. Moreover, the application properties of DWPU on coated polyester fabrics were satisfactory.