Novel colored polyurethane nanoparticle for recyclable dyeing polyester fabric

Abstract

Colored wastewater has to be treated before its discharge, which is a great challenge for the protection of the ecological environment. A novel polymeric dye with nanoparticle morphology has been handily designed to dye polyester fabrics and can be fully recycled to avoid a large number of dyes discharge. It solves the colored wastewater pollution problem in the dyeing process from the source. The colored polyurethane nanoparticles with an average size of 500 nm are prepared via emulsion polymerization. The average content of the colorant monomer on nanoparticle is 2.77%. The colored nanoparticle demonstrates no thermal degradation at 110 °C and no damage under 20 MPa, which means good adaptability for the high-temperature dyeing process. The color depth of dyed polyester fabric can be easily adjusted by changing the concentration of colored nanoparticles in dyebath. The colored nanoparticles in the residual dyebath can be collected by extraction filtration leading to the concentration decreases from 11 mg mL−1 to 0.000025 mg mL−1 after filtered. Both the colored polyurethane nanoparticles and filtered water are fully reused for the next dyeing process to achieve the purpose of avoiding water consumption and residue dyes discharged. This work can promote the development of green and clean dyeing processes in the textile industry.