Chemical conversion of waste PET to valued-added bis(2-hydroxyethyl) terephthalamide through aminolysis

Polyethylene terephthalate (PET) refers to a widely used thermoplastic polymer that is difficult to degrade naturally. Therefore, large amounts of waste PET need to be recycled. In this study, to achieve a green and efficient method to degrade and recycle waste PET for new functional chemicals, PET waste was first swelled with acetic acid. Then, it was degraded under atmospheric pressure at 70 °C for 4 h using ethanolamine as solvent. The degradation efficiency of PET was higher than conventional methods because of the swelling-induced pores caused by the acetic acid. The aminolysis product bis(2-hydroxyethyl) terephthalamide was confirmed by Fourier transform infrared and nuclear magnetic resonance characterization methods and could be readily separated and recovered from the solvent. Finally, the degradation mechanism was discussed. This research provides a feasible and efficient approach to realize the recycling of PET with high value.