Simple fabric-to-fibre recycling of PBT/cotton textile blends using water under mild conditions

Abstract

The increasing global demand for textiles has contributed to a rapid rise in textile waste, particularly from hard-to-recycle polymer mixtures such as polyester/cotton blends, posing major challenges to achieve circularity in this sector. Exemplarily, poly(butylene terephthalate) (PBT)/cotton textile blends are difficult to separate using conventional chemical or physical methods that often involve toxic solvents, high energy input, or produce low-value products. In this study, we present a simple, greener and potentially scalable fabric-to-fibre recycling approach for PBT/cotton fibres using only water and air under ambient conditions. The process is based on the distinct behaviour of PBT and cotton upon dispersion in water, allowing effective separation of both materials in a two-step procedure involving air flushing. Over 94 wt% of the initial fibres were successfully recycled, and structural, thermal and morphological analyses (FTIR, NMR, DSC, DMTA, TGA, XRD and SEM) confirm the chemical identity and morphological integrity of the separated fibres. The process is inherently non-toxic, aligned with green chemistry principles, and exhibited reduced green metrics due to solvent recycling.