Enabling waterless polycotton textile waste recycling via controlled partial depolymerization of polyester

Abstract

Less than 1 % of post-consumer textiles are currently recycled, largely due to the challenge of separating polycotton blends. This study introduces a novel, waterless chemical recycling method for highly pigmented 50/50 polycotton textiles, enabling selective depolymerization of polyester into oligomers while recovering cotton for fibre-to-fibre recycling. The process uses a polar aprotic solvent as a reaction medium with sub-stochiometric ratio of ethylene glycol or glycerol as cleaving agents to partially break down polyester, leaving cotton structurally intact. Polyester-derived oligomers, dyes and pigments remain in the solvent, allowing cotton to be recovered clean, free of residual colorants, minimizing downstream processing. The recovered cotton is blended with kraft pulp and spun into viscose fibres—demonstrating compatibility with existing textile production. This scalable, resource-efficient approach enables simultaneous cotton reuse, polyester oligomers upcycling without purification, and solvent recovery— offering a practical route to reduce virgin cotton use and environmental impact while advancing textile circularity.