Study of regularities of polyethylene terephthalate waste glycolysis and the properties of the final product

Recycling of accumulated PET waste (PET-W) is considered to be a cost-effective development, becomes an important global issue and is in line with the principles of sustainable development. The physicochemical properties of recycled polyethylene terephthalate were determined, and the structure and phase composition of the polymer were evaluated. The results of these studies led to the conclusion that PET does not significantly lose properties during processing, operation in the form of bottles and storage. The exception is the molecular weight value, which decreases to 19900, apparently due to hydrolytic degradation. The analysis of literature data revealed the conditions of glycolysis of polyethylene terephthalate waste. The glycolysis of PET-W was carried out under the defined conditions, the material balance of the process was drawn up, the results of which were used to calculate the degree of conversion of PET-W and the yield of the main product of glycolysis (88%). The glycolysis product was fractionated and physicochemical properties of each fraction were determined. It is shown that the main products of glycolysis are bis(hydroxyethyl)terephthalate and its dimer. This assumption was confirmed by IR and proton NMR spectroscopic studies, DSC analysis and counter synthesis.