Eco-friendly, Expeditious Depolymerization of PET in the Blend Fabrics by Using a Bio-based Deep Eutectic Solvent under Microwave Irradiation for Composition Identification

An eco-friendly, expeditious technique was developed for depolymerization of polyethylene terephthalate (PET) in blend fabric. A completely bio-based deep eutectic solvent (DES), glycerol-choline chloride (GC), could replace conventional toxic solvents commonly used in PET depolymerization. Microwave irradiation was used to facilitate the process with high energy efficiency. The PET portion in 65/35 and 50/50 PET/cotton blends was removed by GC containing 5% NaOH in less than 100 seconds of microwave irradiation. Various instrumental techniques such as FTIR, TGA, SEM, and XRD substantiated the removal of PET from the blend fabrics. The depolymerization mechanism was investigated by analyzing its dissolved residues by HPLC. Finally, a commercial sample with 45/55 PET/cotton was also examined to confirm that the test method developed could have practical application.