Tertiary Recycling of Poly(ethylene terephthalate) Aimed at Obtaining Chemicals and Fuels: A Review

Abstract

Plastics have been an indispensable material in the life of humanity. However, these polymers have a slow degradation process that can lead to contamination of soil, air and water when they are not properly allocated. Since the poly (ethylene terephthalate)-PET is one of the most commonly consumed thermoplastic resins in Brazil and with a short time of use, it is normal to find it being discarded in landfills, streets, lakes and garbage dumps. Consequently, the recycling of plastic waste is an alternative for avoiding environmental and social problems. In this paper we describe the recycling methods for reuse of plastic waste, mainly the tertiary recycling of PET using the pyrolysis process. Tertiary recycling-pyrolysisof PET is important because it reduces costs of pre-treatment, collection and selection, and allows the obtaining of both a combustible substance and chemicals used for the obtaining of the polymer which gave it origin or even a new polymer, thus eliminating the risk of using recycled PET for packaging foods, beverages and pharmaceuticals.

PET Recycling by Alcoholysis Using a New Heterogeneous Catalyst: Study and its Use in Polyurethane Adhesives Preparation

“…After this, the polyol was dissolved in acetone followed by addition of a drying agent (anhydrous sodium sulfate) and filtered in Büchner funnel. The filtered fraction (containing the PET polyol) was evaporated and the product was characterized by GPC, NMR and hydroxyl value …”

“…Among chemical techniques such as methanolysis, glycolysis or hydrolysis, the alcoholysis method is one of the used methods and has been extensively applied to PET recycling due the possibility of obtaining products with different molar weights and physical properties by means of modifying the reaction conditions such as temperature, amount of the polymer, amount and type of the alcohol, amount and nature of catalyst and pressure . Other chemical recycling methods have been mentioned in literature such as aminolysis using aminoethanolamine and zinc acetate as catalyst.…”

Chemical Recycling Processes of Waste Polyethylene Terephthalate Using Solid Catalysts

“…Alcoholysis of PET is a transesterification reaction in which the backbone ester linkage of PET breaks to form alkyl terephthalate and EG. [129] This is one of the most preferred methods since diverse products with varying molecular weights and physical properties can be obtained by changing the process conditions like reaction temperature, reaction pressure, quantity of alcohol, polymer content, and catalyst loading. [130] Different alcohols such as ethanol, butanol, benzyl alcohol, trimethylolpropane, 2ethyl-1-hexanol, etc.…”

Comportamento Reológico, Mecânico, Termomecânico E Morfológico De Blendas De Poliestireno/Resíduo De Calçados Com Diferentes Granulometrias

“…Nos últimos anos a prática da reciclagem tem sido incentivada em um esforço para aumentar a conscientização sobre as questões ambientais, devido a grande quantidade de resíduos gerados nos processos de fabricações, e consequentemente promover a redução dos recursos utilizados [1]. Atualmente, destaca-se o crescente consumo de materiais à base de polímeros, impulsionado pela diversidade de propriedades e características.…”