Chemical Recovery of Useful Chemicals from Polyester (PET) Waste for Resource Conservation: A Survey of State of the Art

Lorenzetti, Cesare; Manaresi, P.; Berti, Corrado; Barbiroli, Giancarlo

doi:10.1007/s10924-005-8711-1

Cited by 95 publications

(56 citation statements)

References 20 publications

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“…Structural deformation and production of lower quality materials during recycling process, called down-cycling, can be avoided up to the second polymer recycling generation using the chemical depolymerization process [4]. The tertiary recycling processes transform waste PET into raw materials that can be reused for manufacturing new products [5,6]. PET waste can be depolymerized by transesterification using various agents, such as water (hydrolysis), acids or bases [7,8], alcohols (alcoholysis) [9][10][11], amines (aminolysis) [12], and glycols (glycolysis) [13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Effect of the modified silica Nanofiller on the Mechanical Properties of Unsaturated Polyester Resins Based on Recycled Polyethylene Terephthalate

et al. 2015

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Unsaturated polyester resin (UPe)-based nanocomposites and fumed silica Aerosil R812S, R805 and R816, and R200 modified with phenyl terminal group, R200NPh, were prepared. UPe resins were synthesized from maleic anhydride and products of glycolysis, obtained by polyethylene terephthalate depolymerization with dipropylene glycol in the presence of tetrabutyl titanate catalyst. The obtained unsaturated polyesters were characterized by acid, hydroxyl, and iodine values and by FTIR and NMR analysis. The microstructural analysis of the prepared nanocomposites, performed by using transmission electron microscopy, confirmed that silica nanoparticles formed chain-like aggregates in the polymer matrix. The presence of modified silica nanoparticles had no influence on the glass transition temperature and thermal stability of polyester matrix.

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Section: Introductionmentioning

confidence: 99%

Effect of the modified silica Nanofiller on the Mechanical Properties of Unsaturated Polyester Resins Based on Recycled Polyethylene Terephthalate

et al. 2015

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“…Within the context of alkaline hydrolysis of PET a potentially active PTC should efficiently transport the hydroxide anion from the aqueous phase to the organic phase (solid PET), thereby increasing the reaction rate. Recent studies have only evaluated the role of quaternary ammonium salts [ 1 [2][3][4][5][6][7][8][9][10][11][12][13][14]; however, no attention has been paid to examining the behaviour of tetralkyl phosphonium salts as PTCs (table 1) for this specific reaction system. For this screening study the following operating conditions were used: stirring rate 400 rpm, particle size 250 µm, inert atmosphere 200 kPa N 2 , temperature 80 ºC, NaOH concentration 1.67 mol l -1 , PET concentration 0.29 mol l -1 , and PTC concentration 0.07 mol l -1 .…”

Section: Alkaline Hydrolysis Of Pet Assisted By Phase Transfer Catalystsmentioning

confidence: 99%

“…The chemical recycling of PET can be conducted by means of the following processes: (i) glycolysis, (ii) methanolysis, (iii) hydrolysis and (iv) aminolysis or ammonolysis. All these methods have been recently reviewed by Paszun and Spychaj [3], Karayannidis and Achilias [4] and Lorenzetti et al [5]. Nowadays there is a growing interest in hydrolysis for the chemical recycling of PET, since it is the only method that leads to terephthalic acid (TPA) and ethylene glycol (EG) as reaction products, i.e., the monomers from which PET is formed.…”

Section: Introductionmentioning

confidence: 99%

Chemical recycling of PET by alkaline hydrolysis in the presence of quaternary phosphonium and ammonium salts as phase transfer catalysts

López‐Fonseca

González-Marcos

González‐Velasco

et al. 2008

WIT Transactions on Ecology and the Environment

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Chemical or tertiary recycling of waste polymers including PET, poly(ethylene terephthalate), is the only method according to the principles of Sustainable Development, since it leads to the formation of the raw materials (monomers) from which the polymer is made of. This work has been focused on the determination of the kinetics of the depolymerisation of PET by means of alkaline hydrolysis and on the identification of the catalytic behaviour, if any, of a series of phosphonium and ammonium salts as phase transfer catalysts (9 salts with varying alkyl groups, central cation (N or P) and anion (Cl -, Br -, I -, OH -)). Among the catalysts tested tributylhexadecylphosphonium bromide (3Bu6DPB) is found to be the most effective catalyst. Complete conversion of PET with considerably low catalyst concentration and temperature can be achieved. The selected phase transfer catalyst fulfils the requirements of having enough character in order to be lipophilic, while small enough in order to avoid steric hindrance. The time for complete hydrolysis (>90% conversion) of solid PET under alkaline conditions with 3Bu6DPB at 80 ºC is 1.5 hours and 10 hours without 3Bu6DPB.

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“…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].…”

Section: Introductionmentioning

confidence: 99%

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

Geyer¹,

Lorenz²,

Kandelbauer³

2016

Express Polym. Lett.

204

120

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Abstract.Recycling of poly(ethylene terephthalate) (PET) is of crucial importance, since worldwide amounts of PETwaste increase rapidly due to its widespread applications. Hence, several methods have been developed, like energetic, material, thermo-mechanical and chemical recycling of PET. Most frequently, PET-waste is incinerated for energy recovery, used as additive in concrete composites or glycolysed to yield mixtures of monomers and undefined oligomers. While energetic and thermo-mechanical recycling entail downcycling of the material, chemical recycling requires considerable amounts of chemicals and demanding processing steps entailing toxic and ecological issues. This review provides a thorough survey of PET-recycling including energetic, material, thermo-mechanical and chemical methods. It focuses on chemical methods describing important reaction parameters and yields of obtained reaction products. While most methods yield monomers, only a few yield undefined low molecular weight oligomers for impaired applications (dispersants or plasticizers). Further, the present work presents an alternative chemical recycling method of PET in comparison to existing chemical methods.

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Chemical Recovery of Useful Chemicals from Polyester (PET) Waste for Resource Conservation: A Survey of State of the Art

Cited by 95 publications

References 20 publications

Effect of the modified silica Nanofiller on the Mechanical Properties of Unsaturated Polyester Resins Based on Recycled Polyethylene Terephthalate

Effect of the modified silica Nanofiller on the Mechanical Properties of Unsaturated Polyester Resins Based on Recycled Polyethylene Terephthalate

Chemical recycling of PET by alkaline hydrolysis in the presence of quaternary phosphonium and ammonium salts as phase transfer catalysts

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

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