Complete recycling of polymers and dyes from polyester/cotton blended textiles via cost-effective and destruction-minimized dissolution, swelling, precipitation, and separation

Abstract

The lack of economic dye-polymer and fiber-fiber separations for blended textiles prevents large-scale textile recycling. We focus on a clean, cost-effective, and destruction-minimized fiber-to-fiber recycling, suitable for polyester/cotton blended textiles. Here, dyed polyester was dissolved and separated from the blend, followed by controllable polyester precipitation to retain its dyes separately in the solution. The remaining-colored cotton was swollen to remove its dyes after cleavage of dye-cellulose bonds. Colorless polyester and cotton were regenerated into fibers with similar and 60 % higher tenacity than those before the recycling, respectively. Recycled fibers also had desirable dyeability, including dye exhaustion and colorfastness, after being dyed with the dyes extracted from the polyester/cotton blends, via our newly developed solvent dyeing system. More than 99 % of the solvent used in the recycling was recycled. Our recycling had a cost and energy consumption of less than 20 % of the production of virgin materials.