Glycolysis of poly(ethylene terephthalate) waste with diethyleneglycol under microwave irradiation and ZnSO4·7H2O catalyst

Hoang, Cuong Ngoc; Le, Thuyen T. N.; Hoang, Quy D.

doi:10.1007/s00289-018-2369-z

Cited by 29 publications

(19 citation statements)

References 12 publications

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“…The volatile materials were isolated and characterized by GC-MS as a mixture of water and the decomposition products of M and D, such as 1,4-dioxane, acetaldehyde, 2-methyl-1,3-dioxolane, etc. [18].…”

Section: Resultsmentioning

confidence: 99%

“…The longest chain of this series was MD 3 that was created from at least three new ether bonds among one M and three D units, corresponding to an initial DEG/PET molar ratio of 2.5/1. This homologous oligoether series was not detected in the LC-MS result of the sample obtained after treatment with an aqueous 20% NaCl solution [18], because the components had a high solubility, even in brine solution, and were removed from the final product mixture.…”

Section: Resultsmentioning

confidence: 99%

“…Even though DEG was used in excess, the LC analysis showed that the quantity of unreacted DEG reactant in the oligodiol product was small due to the transesterification and ether formation occurring simultaneously and reaching an equilibrium state to form the oligo-ester-ether-diol. For this reason, purification by treatment with a cool 20% NaCl solution [18] was unnecessary. In this research project, we use the glycolyzed product mixture directly for PU synthesis without purification steps, therefore, no additional waste is created, and a larger quantity of diol from waste PET is used.…”

Section: Resultsmentioning

confidence: 99%

“…In addition, the oligodiol obtained from the PET-DEG reaction is partly soluble in water; therefore, product purification and catalyst removal or recovery are almost impossible. In our research paper [18], we found that ZnSO 4 ·7H 2 O was significantly better than the commonly used zinc acetate for PET glycolysis. The reactions were conducted under microwave irradiation, for effective energy usage, with a low initial DEG/PET ratio, and the liquid product exhibited a bright color.…”

Section: Introductionmentioning

confidence: 99%

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Novel Oligo-Ester-Ether-Diol Prepared by Waste Poly(ethylene terephthalate) Glycolysis and Its Use in Preparing Thermally Stable and Flame Retardant Polyurethane Foam

et al. 2019

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Rigid polyurethane foam (PUF) was successfully prepared from a novel oligo-ester-ether-diol obtained from the glycolysis of waste poly(ethylene terephthalate) (PET) bottles via reaction with diethylene glycol (DEG) in the presence of ZnSO4 7H2O. The LC-MS analysis of the oligodiol enabled us to identify 67 chemical homologous structures that were composed of zero to four terephthalate (T) ester units and two to twelve monoethylene glycol (M) ether units. The flame retardant, morphological, compression, and thermal properties of rigid PUFs with and without triphenyl phosphate (TPP) were determined. The Tg values showed that TPP played a role of not only being a flame retardant, but also a plasticizer. PUF with a rather low TPP loading had an excellent flame retardancy and high thermal stability. A loading of 10 wt % TPP not only achieved a UL-94 V-0 rating, but also obtained an LOI value of 21%. Meanwhile, the PUF without a flame retardant did not achieve a UL-94 HB rating; the sample completely burned to the holder clamp and yielded a low LOI value (17%). The fire properties measured with the cone calorimeter were also discussed, and the results further proved that the ﬂame retardancy of the PUF with the addition of TPP was improved significantly. The polymeric material meets the demands of density and compression strength for commercial PUF, as well as the needs of environmental development. The current study may help overcome the drawback of intrinsic high ﬂammability and enlarge the ﬁre safety applications of materials with a high percentage of recycled PET.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Novel Oligo-Ester-Ether-Diol Prepared by Waste Poly(ethylene terephthalate) Glycolysis and Its Use in Preparing Thermally Stable and Flame Retardant Polyurethane Foam

et al. 2019

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“…Having implemented glycolysis at a temperature ranging from 170 C to 175 C prepared by microwave irradiation and using ionic liquid catalyst, the complete depolymerization of PET (up to 100%) with a BHET yield of 64% was attained. 163 Microwaved-assisted depolymerization of PET in the presence of DEG was reported by Hoang et al 164 with methylene diphenyl diisocyanate (MDI) to produce rigid polyurethane foam. 165 3 | OVERVIEW OF THE METHODS Table 1…”

Section: Glycolysismentioning

confidence: 99%

Chemical recycling ofPET: A stepping‐stone toward sustainability

Shojaei

Abtahi

Najafi

2020

Polymers for Advanced Techs

168

113

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This paper focuses explicitly on the chemical approaches involved in the recycling of polyethylene terephthalate (PET). Due to the high rate of consumption as well as nonbiodegradability, PET plays a crucial role as one of the most significant sources of accumulated waste in the landfill which jeopardizes our planet. To address this issue as well as increased environmentally conscious, running out of landfill space, natural resource, and energy conservation, and producing value-added chemicals to use as building block or co-products, the chemical recycling methods have been evolved. Therefore, there has been an attempt to have a comprehensive review of the five types of conventional recycling methods namely hydrolysis, methanolysis, glycolysis, aminolysis, and ammonolysis studied by researchers over the last two decades. In this regard, the influence of diverse depolymerization reaction variables for instance, traditional catalyst, temperature profile, ionic liquid catalysts, phase transfer catalyst, microwave assistance, etc was reported. Moreover, the upsides and downsides of each technique were considered.

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Highly efficient fire retardant behavior, thermal stability, and physicomechanical properties of rigid polyurethane foam based on recycled poly(ethylene terephthalate)

Pham

Nguyen

Phan

et al. 2020

J of Applied Polymer Sci

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This study focused on the burning phenomena, thermal stability, and physicomechanical properties of polyurethane foam based on recycled poly(ethylene terephthalate) (RPUF) with and without halogen‐free flame retardants (FRs). Flammability behavior and associated mechanisms were studied by cone calorimetry, LOI, UL 94, FTIR, TGA, FE‐SEM, and XPS. The results of cone calorimeter testing indicate improved FR performance with notable reductions in peak heat release rate (~39.1%), peak CO production (~61.7%), and peak CO2 production (~43.0%). LOI values significantly increase, up to 29.5–47.1%, in the presence of FRs, and V‐0 ratings are attained even at a rather low loading of FR (6.07 wt%). Meanwhile, the RPUF completely burns to the holder clamp with a low LOI value (17%), and it do not pass the UL94 HB standard. The addition of FRs notably improves the residual char of RPUF, indicating that FRs contributed to the formation of a barrier layer to protect RPUF during degradation. The comparison between experimentally determined TGA results and calculated values provides support for the effect of FRs on the thermal degradation behavior of RPUF. Sorption isotherm experiments of RPUF/FR systems show low moisture absorptivity and a weak hysteresis effect due to strong intermolecular bonds between RPUF and added FRs. The compression test, density, and morphology of foam samples are also discussed.

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Glycolysis of poly(ethylene terephthalate) waste with diethyleneglycol under microwave irradiation and ZnSO4·7H2O catalyst

Cited by 29 publications

References 12 publications

Novel Oligo-Ester-Ether-Diol Prepared by Waste Poly(ethylene terephthalate) Glycolysis and Its Use in Preparing Thermally Stable and Flame Retardant Polyurethane Foam

Novel Oligo-Ester-Ether-Diol Prepared by Waste Poly(ethylene terephthalate) Glycolysis and Its Use in Preparing Thermally Stable and Flame Retardant Polyurethane Foam

Chemical recycling ofPET: A stepping‐stone toward sustainability

Highly efficient fire retardant behavior, thermal stability, and physicomechanical properties of rigid polyurethane foam based on recycled poly(ethylene terephthalate)

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