Selective depolymerization and recovery of elastane via aminolysis using secondary amines

Elastane (EL) improves comfort, fit, and stretchability in textile blends, but its presence, even at low contents (2 to 10 wt%), hinders textile recycling. Selective EL removal is therefore essential for a sustainable textile economy. Here, a selective EL depolymerization strategy for PET-based textiles using secondary amines is presented. Diethylamine proved the most effective splitting agent, combining high carbamate cleavage rates, excellent selectivity (>99.9%), and efficient recovery by distillation. The addition of a polar co-solvent enabled complete EL removal within 40 min at 130 °C. The treated textiles retained their mechanical performance, confirming suitability for recycling. The process was also applicable to polyamide, cotton, and polyacrylonitrile-based blends. Scale-up yielded an EL-free PET fraction with efficient EL removal. Furthermore, EL degradation products were successfully valorized through hydrolysis into high-value methylenedianiline and polyol building blocks with isolated yields of 85% and 89%, respectively.