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The effect of xylene as aromatic solvent to aminoglycolysis of post consumer PET bottles



This study deals with the use of ethylene glycol and diethylamine for the aminoglycolytic degradation of waste poly(ethylene terephthalate) (PET). Our aim is to investigate how the product composition changes according to depolymerization conditions and to obtain oligomer mixtures having different properties. For this purpose, simultaneous aminolysis–glycolysis reactions of postconsumer soft-drink PET bottles were carried out in a high pressure reactor with or without xylene. As a result, the oligomer mixtures having carboxyl, hydroxyl, and amine end groups were obtained at the end of the aminoglycolysis of PET. All products were characterized by acid value, hydroxyl value, and amine value determinations as well as by Fourier Transform Infrared Spectroscopy and Differential Scanning Calorimeter. Use of xylene has provided initially easily mixable low viscosity dispersions and depolymerization reactions proceeded more easily. It also provided water soluble and lower molecular weight oligomers with deep depolymerization of PET in the presence of xylene. In case of using xylene, glycolysis reaction was dominant reaction rather than aminolysis and hydrolysis. Functional oligomer mixtures obtained from degradation of waste PET can be used for synthesis of coating materials, such as water reducible alkyd resins and epoxy resins. POLYM. ENG. SCI., 53:2429–2438, 2013. © 2013 Society of Plastics Engineers