scholarly journals Chemical Upcycling of PET Waste towards Terephthalate Redox Nanoparticles for Energy Storage

2021 ◽  
Vol 2 (4) ◽  
pp. 610-621
Author(s):  
Nicolas Goujon ◽  
Jérémy Demarteau ◽  
Xabier Lopez de Pariza ◽  
Nerea Casado ◽  
Haritz Sardon ◽  
...  

Over 30 million ton of poly(ethylene terephthalate) (PET) is produced each year and no more than 60% of all PET bottles are reclaimed for recycling due to material property deteriorations during the mechanical recycling process. Herein, a sustainable approach is proposed to produce redox-active nanoparticles via the chemical upcycling of poly(ethylene terephthalate) (PET) waste for application in energy storage. Redox-active nanoparticles of sizes lower than 100 nm were prepared by emulsion polymerization of a methacrylic-terephthalate monomer obtained by a simple methacrylate functionalization of the depolymerization product of PET (i.e., bis-hydroxy(2-ethyl) terephthalate, BHET). The initial cyclic voltammetry results of the depolymerization product of PET used as a model compound show a reversible redox process, when using a 0.1 M tetrabutylammonium hexafluorophosphate/dimethyl sulfoxide electrolyte system, with a standard redox potential of −2.12 V vs. Fc/Fc+. Finally, the cycling performance of terephthalate nanoparticles was investigated using a 0.1 M TBAPF6 solution in acetonitrile as electrolyte in a three-electrode cell. The terephthalate anode electrode displays good cycling stability and performance at high C-rate (i.e., ≥5C), delivering a stable specific discharge capacity of 32.8 mAh.g−1 at a C-rate of 30 C, with a capacity retention of 94% after 100 cycles. However, a large hysteresis between the specific discharge and charge capacities and capacity fading are observed at lower C-rate (i.e., ≤2C), suggesting some irreversibility of redox reactions associated with the terephthalate moiety, in particular related to the oxidation process.

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Abbas Ahmad Adamu ◽  
Norazilawati Muhamad Sarih ◽  
Seng Neon Gan

Purpose Poly(ethylene terephthalate) (PET) waste from soft drink bottles was incorporated into palm olein alkyd to produce new polyol for use in polyurethane resins as surface protection on metal surfaces. Design/methodology/approach Alkyd was prepared from palm olein, glycerol and phthalic anhydride. PET underwent simultaneous glycolysis and transesterification reactions with the alkyd. Varying the amount of PET has led to polyols with different viscosities. Polyurethane resins were produced by reacting the polyols with toluene diisocyanate. The resins were coated on mild steel panels and cured. Performances of the cured films were tested. Findings The polyurethanes (PU) resin cured to a harder film with better thermal stability. Films showed excellent adhesion properties, while higher content of PET exhibited higher pencil hardness, better water, salt, acid and alkali resistance. Research limitations/implications Other vegetable oils could also be used. The alkyd structure could be changed by formulation to have different functionality and the ability to incorporate higher amount of PET waste. Rate of glycolysis of PET could be increased by higher amount of ethylene glycol. Practical implications This method has managed to use waste PET in producing new polyol and PU resins. The cured films exhibit good mechanical and chemical properties, as well as excellent adhesion and thermal stability. Social implications The non-biodegradable PET has created environmental pollution problems connected to littering and illegal landfilling. It has become necessary to pay greater attention to recycling PET bottles for obtaining valuable products. Originality/value This approach is different from the earlier reports, where PET was recycled to recover the raw materials.


Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 236 ◽  
Author(s):  
Cuong N. Hoang ◽  
Chi T. Pham ◽  
Thu M. Dang ◽  
DongQuy Hoang ◽  
Pyoung-Chan Lee ◽  
...  

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.


2021 ◽  
Author(s):  
Medhat S. Farahat Khedr

Abstract The glycolysis products of polyethylene terephthalate (PET) waste represent a potential source for many value-added products that contain terephthalate repeating units in their backbones. Terephthalate repeating units were not attained directly from terephthalic acid due to its high melting point in addition to its tendency to sublime before it reacts. Glycolysis of PET provides an excellent solution for recycling polymer waste and constitutes a substantial starting material for manufacturing materials with high mechanical stress, such as unsaturated polyesters and polyurethane products. In this study, PET was first depolymerized by glycolysis, and glycolyzed products were then dimerized by reaction with toluene di-isocyanate TDI with half equivalence of their hydroxyl groups for the purpose of inserting urethane blocks into the oligomer structure. The remaining half equivalence of terminal hydroxyl groups was modified into acrylate groups by an acrylation reaction. The acrylated oligo urethane ester products were crosslinked with different co-monomers and tested for UV curability and mechanical properties, and they showed outstanding results.


2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Qun Feng Yue ◽  
Hua Guang Yang ◽  
Mi Lin Zhang ◽  
Xue Feng Bai

Poly(ethylene terephthalate) (PET) waste from local market was depolymerized by ethylene glycol (EG) in the presence of metal-containing ionic liquids, and the qualitative analysis showed that the bis(hydroxyethyl) terephthalate (BHET) was the main product in this process. Compared with other metal-containing ionic liquids, [Bmim]ZnCl3was considered the best catalyst in the glycolysis of PET. When the reaction temperature was 180°C, the conversion of PET reached 97.9% and the BHET was yielded to 83.3% within 5 h. At the same time, [Bmim]ZnCl3could be reused for six times without obvious decrease in the yield of BHET. Additional, the effects of waste PET’s source and size were investigated.


2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Masaki Nakaya ◽  
Kenji Kodama ◽  
Shigeo Yasuhara ◽  
Atsushi Hotta

In an attempt to enhance the gas barrier enhancement of plastic containers such as poly(ethylene terephthalate) bottles, a novel method was found using a hot wire CVD technique, where tantalum wire is heated and exposed to a gas flow of vinyl silane. The resultant SiOC thin film was confirmed to characteristically contain Si-Si bonds in its surface and demonstrate a remarkably and highly practical decrease of the permeation of various gas through poly(ethylene terephthalate) bottles.


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