A waterborne polyurethane-based polymeric dye with covalently linked disperse red 11

A red fluorescent sulfonated waterborne polyurethane-based dye WPU-DR11 was synthesized by conjugating Disperse Red 11 (DR11) into polyurethane backbones. The expected structure of WPU-DR11 was characterized by FT-IR and UV–vis spectra. Containing the well-known dye of anthraquinone chromophores , WPU-DR11 exhibits intriguing optical behaviors. Compared with DR11, WPU-DR11 shows an obvious bathochromic shift in absorption spectra , whereas a evident hypsochromic shift in emission spectra. The fluorescence intensity of WPU-DR11 is dramatically enhanced compared with that of DR11. The fluorescence intensity of WPU-DR11 increases with the temperature, which is different from that of ordinary fluorescent materials. It is found that the fluorescence intensity of WPU-DR11 gradually increase with the increase of concentration, and then decrease. Migration rate of WPU-DR11 are only 2.0–4.0%, which is well below migration rate of DR11. The polyester fibers dyed with WPU-DR11 show high color yield, excellent breaking strength retention, good air permeability and anti-wrinkle resistance. According to the experimental results, WPU-DR11 exhibits excellent fluorescent and dyeing performance.