Depolymerization of Poly(ethylene terephthalate) Waste Using 1,4-Butanediol and Triethylene Glycol

Polyethylene terephthalate (PET) wastes were depolymerized using 1,4-butanediol (BD) and triethylene glycol (TEG) in the presence of zinc acetate as a transesterification catalyst. The glycolyzed products were analyzed for hydroxyl and acid values and identified by elemental analysis, GPC, 1H NMR, 13C NMR, differential scanning calorimeter (DSC) and mass spectra techniques. It was found that the glycolyzed products consist mainly of bis-(hydroxybutyl terephthalate) monomer and dimer by using 1,4-butanediol. The depolymerization using TEG resulted in products of TEG-(TPA- TEG) n for n = 1−3. All glycolyzed products had a low acid value indicating the presence of a minor fraction of terephthalate oligoesters.