New Application of Off-grade Poly (ethylene terephthalate) via Partial Glycolysis Method

Polyethylene terephthalate (PET) is one of the versatile plastics and widely used in the manufacture of various kinds of packaging, especially for soft drink bottles, fibres and films [1]. The effective use of PET wastes is a significant subject for environmental protection researchers. In recent years PET waste is used for production of specialized products such as raw materials for the synthesis of saturated and unsaturated polyesters [2, 3]. Among several methods proposed for chemical recycling of waste PET, glycolysis method makes it possible to employ very low amounts of reactants as well as application of lower temperatures and pressures in contrast with other methods such as supercritical methanol and thermal degradation [4], while hydrolysis under acidic or basic conditions may cause corrosion and pollution problems [5]. Chen et al. [6] found that the glycolysis conversion is almost 100% at 190 °C, 1.5 h glycolysis time and 0.002 mol catalyst (cobalt acetate). But the glycolysis conversion was calculated by depolymerized PET, and the depolymerization reaction into monomer was incomplete. However, to our knowledge, no study has been led to depolymerize off-grade PET by partial glycolysis method in order to synthesize oligomers for applying in nanocomposite materials. In this paper, off-grade PET (melting point of 250-260°C) was glycolyzed into oligomers (melting point of 170-180°C) to prepare compatiblizing agents for PET nanocomposites