Synthesis and application of a phosphorus-containing waterborne polyurethane based polymeric dye with excellent flame retardancy

To endow waterborne polyurethane (WPU) with bright color and improve the flame retardancy, a series of flame-retardant and colorful WPU (DOWPU) was synthesized by incorporating anthraquinone chromophore (DV26) and phosphorus-containing flame-retardant (OP550) into the skeleton simultaneously. The migration property, thermal performance and flame retardancy of DOWPU were systematically characterized by a series of experiments, showing that DOWPU was endowed with bright color and satisfactory flame retardancy. Interestingly, the synergistic effect between DV26 and OP550 made the char yield of DOWPU as high as 25.14 %, which increased the limiting oxygen index by 8.1 %. Furthermore, the migration percentage of DOWPU was only 3.9 %, which was attributed to the strong covalent bonding force between DV26 and polymer chains. Additionally, we coated DOWPU on the polyester fabrics to prove the practicality. The coated fabrics not only had bright colors, but also exhibited excellent color fastness and flame retardancy.