Investigating how the dye colour is impacted when chemically separating polyester-cotton blends

Blended textile fabrics with dyed cotton and polyester (PET) fibres intimately mixed are extensively used in the textile industry. Separating and recycling these blends cannot be performed by conventional mechanical or chemical recycling processes, and this is contributing significantly to the global textile waste problem. Here we demonstrate an approach to separate coloured cotton and polyester blends, and the dye is retained in the separated polyester and cotton components. The separation was achieved via chemical dissolution of cotton using a co-solvent system of ionic liquid and dimethyl sulfoxide, from which regenerated cellulose fibres could be directly wet spun. The polyester component was left intact and recovered via filtration. The recovered products were characterised for thermal, chemical, mechanical, colour strength, and morphological properties.