Chemical Recycling of Postconsumer Poly(ethylene-terephthalate) Bottles – Depolymerization Study

A. Ptiček Siročić, A. Fijačko and Z. Hrnjak-Murgić

Abstract
Poly(ethylene-terephthalate), PET bottles waste was chemically recycled by glycolysis process. The glycolysis reaction was carried out at three temperatures 170, 180 and 190 °C in different time intervals (1, 3, 6 hours) with a weight ratio of ethylene glycol (EG) to PET 1 : 18 and the zinc acetate as a catalyst. The glycolysis reaction leads to formation of monomers bis(2-hydroxyethyl)terephthalate (BHET) and ethylene glycol as well as various types of PET oligomers. Depolymerization products were further characterized by infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). From the results it can be seen that remained PET products i.e. oligomers are thermally very stable and they are suitable for obtaining other polymers.

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Keywords
Bis(2-hydroxyethyl)terephthalate, chemical recycling, glycolysis, oligomers, poly(ethylene-terephthalate)