New separation process for elastane from polyester/elastane and polyamide/elastane textile waste

Elastane, also known as spandex, is a synthetic polymer fibre based on polyurethane, which increases the flexibility and comfort of textile products but causes profound challenges in textile waste recycling. Although the elastane problem is widely known, no process has been demonstrated that allows separation of elastane from other materials. In this study, a feasible and up-scalable elastane separation process based on a non-hazardous selective solvent is successfully realised. Six different organic solvents were chosen and investigated by Hansen solubility parameters and experiments were conducted on polyester/elastane and polyamide/elastane textile waste samples. The non-hazardous solvent dimethyl sulfoxide (DMSO) was determined the most favourable and runs circular within a three-step purification. Principle component analysis (PCA) of spectroscopic measurements (ATR-FTIR) revealed excellent results for the recovered polyester and polyamide. Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) on textile samples proved the success of the developed process.