Hydrolytic Depolymerization of Polyethylene Terephthalate by Reactive Extrusion

Yalçınyuva, Tuncer; Kamal, Mohsin; Lai-Fook, R. A.; Özgümüş, Saadet

doi:10.3139/217.1587

Cited by 24 publications

(7 citation statements)

References 1 publication

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“…An autocatalytic mechanism was suggested, which indicated that the carboxyl groups produced during the reaction catalyzed some of the hydrolytic depolymerization of PET. Continuous hydrolytic depolymerization of PET was also carried out at high temperatures and pressures in a co‐rotating twin screw extruder 46. Low‐molecular‐weight products were obtained at low residence times, suggesting high depolymerization rates.…”

Section: Pet Chemical‐recycling Techniquesmentioning

confidence: 99%

Chemical Recycling of Poly(ethylene terephthalate)

Karayannidis

Achilias

2007

Macro Materials & Eng

304

228

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This paper covers the recent research carried out by the authors on the chemical recycling of poly(ethylene terephthalate) (PET) taken from post‐consumer soft‐drink bottles. The chemical recycling techniques used are critically reviewed and the authors' contribution is highlighted. Hydrolysis in either an alkaline or acid environment was employed in order to recover pure terephthalic acid monomer that could be repolymerized to form the polymer again. Alkaline hydrolysis was carried out in either an aqueous NaOH solution or in a non‐aqueous solution of KOH in methyl cellosolve. A phase‐transfer catalyst was introduced in alkaline hydrolysis, in order that the reaction takes place at atmospheric pressure and in mild experimental conditions. The reaction kinetics were thoroughly investigated, both experimentally and theoretically, using a simple, yet precise, kinetic model. Moreover, glycolysis was examined as an effective way for the production of secondary value‐added materials. The glycolysated PET products (oligomers) can be used as raw materials for the production of either unsaturated polyester resins (UPR) or methacrylated oligoesters (MO). UPR can subsequently be cured with styrene in ambient temperature to produce alkyd resins used as enamel paints or coatings. MO are potential monomers that can be cured either by UV irradiation or temperature to produce formulations used as coatings for wood surfaces, paints, or other applications. Thus, recycling of PET does not only serve as a partial solution to the solid‐waste problem, but also contributes to the conservation of raw petrochemical products and energy.magnified image

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Section: Pet Chemical‐recycling Techniquesmentioning

confidence: 99%

Chemical Recycling of Poly(ethylene terephthalate)

Karayannidis

Achilias

2007

Macro Materials & Eng

304

228

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“…For the purpose of chemical recycling of waste PET, there have been reported a number of degradation methods,3–6 among which hydrolysis of PET is an important one. However, due to the insolubility of PET in water, the hydrolysis of PET require severe conditions such as long reaction time, high temperature and pressure, and in presence of a high amount of concentrated acids or bases7–12 or even under supercritical conditions 13. Large quantities of catalyst such as H 2 SO 4 or NaOH used in traditional hydrolysis of PET cannot be reused and can result in other disadvantages such as equipment corrosion, tedious workup procedure, and environmental problem.…”

Section: Introductionmentioning

confidence: 99%

Hydrolysis reaction of poly(ethylene terephthalate) using ionic liquids as solvent and catalyst

Liu

Xiao

et al. 2009

J of Applied Polymer Sci

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The hydrolysis of poly(ethylene terephthalate) (PET) was studied using ionic liquid 1-n-butyl-3-methylimidazolium chloride ([Bmim] C and time 4.5 h, the conversion of PET and the yield of terephthalic acid (TPA) were almost 100% and !88%, respectively. After easily separated from the product, the ionic liquids could be reused eight times without obvious decrease in the conversion of PET and yield of TPA. Hence, an environmental friendly strategy for chemical recycling of PET was developed.

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“…According to previous research reports , the M W of PET decreases in the presence of water, especially under processing at temperatures higher than the melting point of PET. This is the result of the hydrolysis of PET according to the following equilibrium reaction in Scheme .…”

Section: Resultsmentioning

confidence: 74%

“…These results are in good agreement with XRD results that showed no change in gallery spacing of Cloisite Na + in the presence of water. Water is a good swelling agent for Cloisite Na + and a hydrolysis agent for PET ; but the poor affinity between Cloisite Na + and PET as well as strong electrostatic forces between adjacent platelets of Cloisite Na + limit the diffusion of PET chains into the galleries of the pristine clay.…”

Section: Resultsmentioning

confidence: 99%

Effect of water‐assisted extrusion and solid‐state polymerization on the microstructure of PET/Clay nanocomposites

Dini

Mousavand

Carreau

et al. 2013

Polymer Engineering & Sci

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An melt-mixing process has been used to prepare Poly(ethylene terephthalate) (PET)/clay nanocomposites with high degree of clay delamination. In this method, steam was fed into a twin-screw extruder (TSE) to reduce the PET molecular weight and to facilitate their diffusion into the gallery spacing of organoclays. Subsequently, the molecular weight (M W ) reduction of the PET matrix due to hydrolysis by water was compensated by solid-state polymerization (SSP). The effect of the thermodynamic compatibility of PET and organoclays on the exfoliated microstructure of the nanocomposites was also examined by using three different nanoclays. The dispersion of Cloisite 30B (C30B) in PET was found to be better than that of Nanomer I.28E (I28E) and Cloisite Na 1 . The effect of feeding rate and consequently residence time on the properties of PET nanocomposites was also investigated. The results reveal more delamination of organoclay platelets in PET-C30B nanocomposites processed at low feeding rate compared to those processed at high feeding rate. Enhanced mechanical and barrier properties were observed in PET nanocomposites after SSP compared to the nanocomposites prepared by conventional meltmixing.

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Hydrolytic Depolymerization of Polyethylene Terephthalate by Reactive Extrusion

Cited by 24 publications

References 1 publication

Chemical Recycling of Poly(ethylene terephthalate)

Chemical Recycling of Poly(ethylene terephthalate)

Hydrolysis reaction of poly(ethylene terephthalate) using ionic liquids as solvent and catalyst

Effect of water‐assisted extrusion and solid‐state polymerization on the microstructure of PET/Clay nanocomposites

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