Chemical upcycling of poly(ethylene terephthalate) waste: Moving to a circular model

Abstract

The circular economy is a path that society, governments, and business mustadopt to develop a viable and sustainable model for plastic production. Follow-ing the route guided by the United Nations and the new laws of the EuropeanUnion, such as the Green Deal, it will be able to put an end to the great problemof this era, the inadequate treatment and management of plastic waste. On theplastics production ladder, poly(ethylene terephthalate) (PET) ranks fifth along-side polyurethanes, but only an average of 17% of total PET waste is recycled.Moreover, according to the latest survey made by Zero Waste Europe, most ofthis recycling source is used in low features applications through a downcyclingprocess. There are mainly two ways for PET recycling, it can be done mechani-cally or chemically. On the one hand, mechanical recycling is easy to employbut presents some limitations as the properties of the final product decreasefrom the second cycle, whereas chemical recycling offers versatile proceduresalthough it requires huge amounts of investment money. To address these draw-backs, diverse chemical recycling methods, specially aminolysis and glycolysis,were proposed as the promising way to obtain high added-value products. Inthis review, different updated state of the art works about recycling of PET werediscussed, presenting the two forms for recycling PET waste, mechanical andchemical approach, and the reason of why is important to focus on theobtention of high-added value products in an upcycling process.