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Continuously growing adoption of electronic devices in energy storage, human health and environmental monitoring systems increases demand for cost-effective, lightweight, comfortable, and highly efficient functional structures. In this regard, the recycling and reuse of polyethylene terephthalate (PET) waste in the aforementioned fields due to its excellent mechanical properties and chemical resistance is an effective solution to reduce plastic waste. Herein, we review recent advances in synthesis procedures and research studies on the integration of PET into energy storage (Li-ion batteries) and the detection of gaseous and biological species. The operating principles of such systems are described and the role of recycled PET for various types of architectures is discussed. Modifying the composition, crystallinity, surface porosity, and polar surface functional groups of PET are important factors for tuning its features as the active or substrate material in biological and gas sensors. The findings indicate that conceptually new pathways to the study are opened up for the effective application of recycled PET in the design of Li-ion batteries, as well as biochemical and catalytic detection systems. The current challenges in these fields are also presented with perspectives on the opportunities that may enable a circular economy in PET use., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

"Green" thermally stable hardener was synthesized from a PET waste. The rigid molecular linear structure of the new hardener suggests that it will provide the polymer matrix with the necessary physical and mechanical characteristics. It also allows the expectation that cured matrix based on this hardener can provide increased toughness. New hardener was used as a curing agent for three epoxy resins—tetraglycidyl methylenedianiline (TGDMA, 111–117 EEW), diglycidylether of bisphenol A (DGEBA, 170-192 EEW) and solid epoxy resin (SER)—with a medium molecular weight (860–930 EEW) based on DGEBA. The mixtures were found to have the highest Tg for the DGEBA resin, and high of that for TGDMA and SER. According to the DMA analysis for two cured matrices, the hardener proved to be no worse than the standard ones, and made it possible to obtain cured matrices with excellent mechanical properties, which allows us to hope for further application of new hardener cured epoxy matrices in appropriate composite materials at high temperatures. [ABSTRACT FROM AUTHOR]

Copyright of Economics & Environment / Ekonomia i Środowisko is the property of Fundacja Ekonomistow Srodowiska i Zasobow Naturalnych and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

“Green” thermally stable hardener was synthesized from a PET waste. The rigid molecular linear structure of the new hardener suggests that it will provide the polymer matrix with the necessary physical and mechanical characteristics. It also allows the expectation that cured matrix based on this hardener can provide increased toughness. New hardener was used as a curing agent for three epoxy resins—tetraglycidyl methylenedianiline (TGDMA, 111–117 EEW), diglycidylether of bisphenol A (DGEBA, 170-192 EEW) and solid epoxy resin (SER)—with a medium molecular weight (860–930 EEW) based on DGEBA. The mixtures were found to have the highest Tg for the DGEBA resin, and high of that for TGDMA and SER. According to the DMA analysis for two cured matrices, the hardener proved to be no worse than the standard ones, and made it possible to obtain cured matrices with excellent mechanical properties, which allows us to hope for further application of new hardener cured epoxy matrices in appropriate composite materials at high temperatures.

Disposal of plastics in the environment has become a core of anxiety in developing countries, while in the developed countries the focus has additionally been placed on design and manufacture of emerging products from plastic wastes—a somewhat vague yet promising horizon. Central to environmental concerns are poly(ethylene terephthalate) (PET) wastes, mainly from post-consumer bottles. Because of a considerable drop in molecular weight in the course of recycling, recycled PETs are not suitable for engineering uses. An efficient yet reasonably green synthesis route is employed here to convert PET wastes into polyurethane, and then carbon nanotubes (CNTs) was added at different levels to obtain nanocomposites with high mechanical properties. The effects of isocyanate (NCO)/hydroxyl (OH) molar ratio and CNTs content on the morphology, physical and mechanical properties were discussed. Chemical/physical crosslink density was calculated from initial slope of stress–strain curves, Mooney–Rivlin plots, strain-hardening modulus, rubbery-plateau storage modulus and swelling data. High tensile strength (300 MPa) and breaking elongation (160%) of polyurethane/CNTs nanocomposites born from PET wastes seemed promising. Microscopic analyses by AFM, SEM, and TEM gave useful information about distribution of CNTs in polyurethane. Lastly, structural changes were correlated to mechanical properties improvement. [ABSTRACT FROM AUTHOR]

Polyethylene Terephthalate (PET) has been depolymerized by aminolysistechnique using ethanolamine to bis(2-hydroxyethyl) terephthalamide (BHETA). BHETA is a diol along with additional amide linkage as a structural part. It is used as hydroxyl precursor for the synthesis of polyetheramide resin. The conventional polyetheramide resin has been prepared by jatropha oil fatty acid amide and resorcinol. The modification is done in conventional resin with addition of BHETA by replacing fatty amide of oil on 50:50 molar basis. The synthesized resin was characterized by FTIR, 1HNMR and hydroxyl value. The synthesized resins are cured with Melamine Formaldehyde (MF) resin as a hardener and coating is prepared. The coating is evaluated for chemical, mechanical and anticorrosive properties. The anticorrosive performance of BHETA based polyetheramide is further improved by addition of polyaniline at various concentrations in coating system. 3wt% addition of polyaniline in BHETA based polyetheramide resin was shows best anticorrosive properties among all studied formulations. [ABSTRACT FROM AUTHOR]

Recycling of poly(ethylene terephthalate) (PET) is a global concern due to generation of large volume of its post consumer waste and serious environmental problems caused as PET does not decompose in nature readily. Present research work aims at effective recycling of waste PET from soft drink bottles by aminolysis method and further utilization of the recycled product for high performance coating application. In the present study, we report aminoethylenethanolamine (AEEA) which till date is not studied much for chemical recycling of PET, having primary and secondary amine groups together with hydroxyl groups, for aminolysis reaction. The reaction parameters were optimized for conventional and microwave assisted technique by varying the ratio of raw materials, reaction time, temperature and power. The recycled oligomeric product was separated, purified and characterized for determination of amine value, hydroxyl value and by Fourier transform infrared spectroscopy, proton NMR (1H-NMR) spectroscopy. Further polyesteramides were successfully synthesized by partial replacement of neopentyl glycol by aminolyzed oligomeric product along with sebacic acid and phthalic anhydride. These resulting polyesteramides were further cured with commercial polyisocyanate curing agents and applied on mild steel panels. The cured coatings were evaluated for their optical, mechanical, chemical, thermal and anticorrosive properties. The partial replacement of recycled product of PET wastes exhibited comparative coating performance properties with respect to polyester polyol synthesized without any component based on recycled PET waste product. [ABSTRACT FROM AUTHOR]

Polyethylene terephthalate (PET) waste recycling has become a worldwide research interest for industries and academic institutes due its inevitable environmental impact. The main objective of current research work is to target efficient recycling of PET waste from mineral water bottles by the glycolysis method and subsequent use of the recycled product for value-added coating application. In the present study, we report on MP-diol (2-methyl-1,3-propanediol) which is not explored much for the chemical recycling of PET, having a branched aliphatic diol with two primary hydroxyls, for glycolysis reaction. The reaction parameters were optimized for microwave-assisted technique by varying the ratio of raw materials, reaction time, temperature, and power. The reaction parameters were optimized, and the recycled oligomeric product (OPETMPD) was separated, purified, and characterized by chemical and spectroscopic methods. Subsequently, dimethacrylated oligoesters of PET oligomer (UV oligomer) were synthesized by methacrylation of the glycolyzed PET product (OPETMPD). The synthesized UV oligomer was evaluated using chemical and spectroscopic methods. Ultraviolet (UV) radiation-curable formulations were prepared using synthesized UV oligomer and applied on wooden panels. The coatings were cured using UV-curing machine and evaluated for their performance properties. The partial replacement of UV oligomer in UV formulations exhibited comparative coating performance properties with respect to conventional UV formulation. [ABSTRACT FROM AUTHOR]

The catalytic activity of a low priced and non-toxic catalyst (sodium carbonate) was explored in an aminolytic degradation reaction of polyethylene terephthalate (PET) bottle waste with hydrazine monohydrate (HMH). Reactions were carried out with different catalyst concentrations, PET-hydrazine monohydrate ratio, reaction time and reaction temperature so as to optimize the yield of the product. The product (terephthalic dihydrazide (TDH)) having potential commercial applications was characterized by CHN analysis, FTIR spectroscopy, 1H and 13C nuclear magnetic resonance (NMR) spectroscopy, differential scanning calorimetry (DSC) and X-ray powder diffractometry (XRD). The surface morphology of the synthesized product and the PET waste flakes before and during the degradation was investigated with the help of scanning electron microscopy (SEM). The process reported in this paper results in significantly higher yield (84%) of TDH in a shorter reaction time of 3 hours at a relatively lower temperature (65°C) as compared to the uncatalyzed PET-HMH aminolysis reaction. [ABSTRACT FROM AUTHOR]

The degradation of two poly(ethylene terephtalate) (PET) samples from urban and marine wastes (PET-u and PET-m, respectively) has been studied by comparing their properties with those of virgin PET (PET-v) and post-condensed PET for bottle fabrication (PET-ssp). FTIR spectroscopy, DSC analysis, WCA and MFI results have confirmed that all PET residues were degraded. Therefore, the chemical recycling has been evaluated in order to valorize PET-m and PET-u wastes, analyzing the effect of degradation on the process. Glycolysis of degraded and non-degraded PET samples has been carried out in a pressure reactor at 220°C for 30 min. For all the cases almost pure BHET monomer has been obtained: 96.5 and 96.7 % for PET-m and PET-u respectively, values 2 and 13 % higher than those obtained for PET-ssp and PET-v. Obtained results indicate that the initial degradation of PET wastes increases the BHET monomer content in the glycolyzed sample. [Display omitted] [ABSTRACT FROM AUTHOR]

A method has been proposed to rapidly degrade waste PET (polyethylene terphthalate) bottles and recover terephthalic acid (TPA) in good yield. The method involves fusion of PET bottle chips with caustic soda in a china-clay crucible placed on the silicon carbide (SiC) slab by exposure to microwaves in a domestic oven. The PET waste was converted to water-soluble sodium salt of TPA in just 4 minutes. Afterwards, the solution was acidified with HCl to recover TPA in high yield. The method can be used to design environmentally benign and fast industrial prototypes to recycle terephthalic acid from waste PET bottles. [ABSTRACT FROM PUBLISHER]

Abstract: Polyethylene terephthalate in the form of waste fibres and disposable soft drink bottles was subjected to depolymerisation through aminolysis using excess of ethanolamine in the presence of different simple chemicals, namely glacial acetic acid, sodium acetate and potassium sulphate, as catalysts. The product bis(2-hydroxy ethylene)terephthalamide (BHETA) obtained was in its pure form with sufficiently high yields with all the catalysts. The purified product was characterised by elemental analysis, melting point, IR spectroscopy, Nuclear Magnetic Resonance (NMR) and Differential Scanning Calorimetry (DSC). The process of aminolysis reported here is economically viable since yields of BHETA are as high as 91%, it has potential for further reactions to obtain useful products and the chemicals used as catalysts are common and cheaply available. [Copyright &y& Elsevier]

Copyright of Fibres & Textiles in Eastern Europe is the property of Sciendo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)