New Motivation for the Depolymerization Products Derived from Poly(Ethylene Terephthalate) (PET) Waste: a Review

Abstract

Summary: Over the last several decades, the process of recycling polymer waste has been attracting the attention of many scientists working on this issue. Polymer recycling is very important for at least two main reasons: firstly, to reduce the ever increasing volumes of polymer waste coming from many sources: from daily life packaging materials and disposables and secondly, to generate value‐added materials from low cost sources by converting them into valuable materials similar, to some extent, to virgin materials. Poly(ethylene terephthalate) (PET) occupies the top of the list of polymers to be recycled due to its easy recycling by different ways, which, in accordance, give variable products that can be introduced as starting ingredients for the synthesis of many other polymers. PET can by recycled by hydrolysis, acidolysis, alkalolysis, aminolysis, alcoholysis and glycolysis. Glycolysis is the breakdown of the ester linkages by a glycol, resulting in oligomers or oligoester diols/polyols with hydroxyl terminal groups. Oligoesters coming from the glycolysis of PET waste have been well known for a number of decades to be utilized as a starting material in the manufacture of polyurethanes, unsaturated polyesters and saturated polyester plasticizers. But, as a current motivation, we are reporting on a new application for these oligoester diols/polyols by converting the hydroxyl terminals into acrylate/methacrylate groups. These new acrylated/methacrylated oligoesters have been tested as UV curable monomers and gave promising results from the point of view of their curability by UV and their mechanical properties. The new motivations open the potential for the market to apply the depolymerization products of PET waste for UV curable coatings, useful for wood surfaces, paints and other applications.Recycling of PET polymer by different chemical routes.magnified imageRecycling of PET polymer by different chemical routes.

Chemical recycling of poly(ethylene terephthalate). Application to the synthesis of multiblock copolyesters

“…The monomers or higher oligomers obtained can be used as building blocks to synthesize other polymers with higher economical values. For example, saturated and unsaturated polyesters [10][11][12], polyurethanes [13][14][15], coating materials [16][17][18][19] and additives [20][21][22] have been synthesized from such building blocks in recent years. A large number of reagents have been used for glycolysis of PET such as ethylene glycol [23][24][25][26], diethylene glycol [27,28], propylene glycol [29], neopentyl glycol [14], 1,4-butanediol [30,31], and some synthetic oligoesters [32,33].…”

Recycling of poly(ethylene terephthalate) – A review focusing on chemical methods

“…Since life cycle assessment studies showed that re-utilization of PET has a positive effect on energy balance and the reduction of CO 2 emissions, for ecological reasons, the need of an appropriate PET-recycling is greater than ever [3][4][5][6][7]. Thus, several PET-recycling methods have been developed, which were partially reviewed in the literature [8][9][10][11][12][13][14][15]. One of these methods is the incineration of the PETwaste using the released heat of combustion (direct energy recovery), which amounts to about 46 MJ·kg -1 [13,14].…”

“…Thus, several PET-recycling methods have been developed, which were partially reviewed in the literature [8][9][10][11][12][13][14][15]. One of these methods is the incineration of the PETwaste using the released heat of combustion (direct energy recovery), which amounts to about 46 MJ·kg -1 [13,14]. Another method, the pyrolysis of the PETwaste is applied to produce a substitute of coal (carbonization) or aromatic and aliphatic compounds as an alternative for fossil fuels (indirect energy recovery).…”

Hidrólise parcial da superfície do polyethylene terephthalate (PET): transformando um rejeito em um material de troca catiônica para aplicação ambiental

“…A introdução da embalagem de PET no Brasil, em 1988, além de trazer as indiscutíveis vantagens ao consumidor, trouxe também o desafio de sua reciclagem. 2 O PET é um dos polímeros mais reciclados em todo o mundo devido à sua extensa gama de aplicações, tais como fibras têxteis, tapetes, carpetes, não-tecidos, embalagens, filmes, fitas, cordas, compostos, e mesmo incinerado para produção de energia. [3][4][5][6] No Brasil, em 2006, alcançamos o segundo lugar na reciclagem do PET, com aproximadamente 51% das embalagens pós-consumo efetivamente recicladas (193,9 mil toneladas das 378 produzidas), perdendo apenas para o Japão, que reciclou 62%.…”

“…Por esta razão, existe uma grande necessidade de reciclagem do PET por dois motivos: ecológico e econômico. 2 O PET é um polímero termoplástico e pode ser fundido e extrudado para produção de fibras, cordas, tubos e mesmo incinerado para produção de energia. 3 A reciclagem química do PET tem atraído a atenção dos químicos devido à grande variedade de processos, resultando em diferentes produtos.…”