Synthesis, characterization and fluorescence performance of a waterborne polyurethane-based polymeric dye

A novel anionic waterborne polyurethane-based fluorescent dye WPU-DV26 was synthesized by incorporating the molecular structure of disperse violet 26 (DV26) into the polyurethane chain. The structure of WPU-DV26 was confirmed by means of Fourier transform infrared spectroscopy and UV–vis absorption analysis. Comparing to the UV–vis spectrum of DV26, WPU-DV26 showed a hypsochromic shift from the absorption maxima of 518, 558, 609 nm to 510, 548, 586 nm, respectively. WPU-DV26 can form stable latex in water. The number average molecular weight and its distribution index, and average latex particle size for WPU-DV26 were determined to be 2.33×104, 1.36 and 80 nm, respectively. The improved thermal stability of WPU-DV26 can be attributed to the embedded anthraquinone unit of DV26. It was found that both the intensity and stability of the fluorescence of WPU-DV26 latex were improved significantly compared with those of DV26.