Efficient recycling of polyester and microcrystalline cellulose through one-step extraction from waste polyester-cotton blended fabrics with deep eutectic solvents

In order to extract polyester (PET) and microcrystalline cellulose (MCC) from waste polyester-cotton blended fabrics (WPBFs), a deep eutectic solvent (DES) synthesized from choline chloride (ChCl) and p-toluenesulfonic acid (TsOH) was developed as the treatment solvent. The orthogonal experiment method was designed to explore the optimal conditions for the separation process (75 vol.% DES, 110 °C, 10 min). The PET component was easily separated after the degradation of the cotton component from WPBFs. Recycled and untreated products were investigated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermo-gravimetric analysis (TGA), and tensile tests. The results showed that the yields of recycled PET (R-PET) and MCC were 99.20, and 69.46%, respectively. Furthermore, glucose was also obtained with a yield of 38.91%. In particular, there was no significant deterioration in the properties of R-PET. MCC was obtained with crystallinity of 86.46%, which can be applied as the raw material of MCC in various industries. Moreover, the lifetime of the recyclable DES (ChCl/TsOH) showed that its treatment efficiency can still meet the requirement after the fifth recycling.