Search

Resin concretes belong to a small group of building materials which, besides high strength parameters, also have a very good chemical resistance. This is confirmed by the studies carried out by various research institutions around the world. However, there is little data on the behaviour of composite resin exposed to corrosive solutions for an extended period of time. This article presents the results of the research on weight changes in samples of epoxy mortar modified with poly(ethylene terephthalate) glycolysates, immersed for 5 years in four different aggressive media i.e. 10% aqueous solutions of sulphuric and nitric acids, sodium hydroxide, and sodium chloride. The actual average weight changes obtained were compared with the data calculated on the basis of the regression functions fitted to the data recorded after 3.5 years of exposure. This allowed verification of the model selection correctness and evaluation of the effectiveness of the fitted regression curve. In the case of aqueous sodium hydroxide and sodium chloride solutions, it can be assumed that the logarithmic model describes weight changes well. It was observed that the weight of the samples exposed to NaCl solutions and NaOH stabilizes over prolonged monitoring time and reaches a plateau. However, the weight changes in mortar samples immersed for 5 years in aqueous solution of sulphuric and nitric acids quite significantly differ from the data calculated on the basis of the trend line fitted to the results of the tests carried out after 3.5 years of exposure. It seems that the better solution in this case is the selection of an exponential model. In addition, placing the logarithmic trendlines for all corrosive media together on a chart allows to note which of the solutions is the most aggressive. It was found that after 5 years of immersion in aqueous solutions of acids, mortar samples became brittle, and the observation of their fractures confirmed the weakness of the connection on the resin/aggregate phase boundary. Changes in the appearance of the samples were also noted, namely the surface of samples submerged in a solution of nitric acid strongly yellowed, and those treated with sulphuric acid were tarnished.

CO2 emissions from flue gases can be restricted via a promising post-combustion capture technique, namely, adsorption. In the present work, behavior of adsorbents, prepared from PET (polyethylene terephthalate) waste, for CO2 capture studies was investigated to understand the fixed bed adsorption dynamics. The effect of activation on textural properties, surface functional groups and elemental composition was studied through nitrogen adsorption/desorption, XPS, FTIR, and EDX analysis. Thermal stability of adsorbent samples was also evaluated. The kinetics of the adsorption process was studied using Lagergren's pseudo-first-order model, pseudo-second, fractional order, Elovich, and Avrami models. Freundlich isotherm fit confirmed the heterogeneous nature of adsorbent's surface. Adsorption column breakthrough profiles were modeled using linear driving force (LDF) approximation for mass transfer. Model equations were solved using the Method of lines in MATLAB environment. Results show that the model closely approximated the column breakthrough curves for different CO2 concentrations (5–12.5%) and different adsorption temperatures (30–100 °C). [ABSTRACT FROM AUTHOR]

The aim of this work is to report the alternative reuse of poly(ethylene terephthalate) waste based on the preparation of oligomers by catalyzed glycolysis, their deposition onto the surface of stainless steel metallic hollow microspheres and the determination of adsorbent properties toward lead, nickel and cadmium cations in aqueous solutions. The coated microspheres were characterized by field emission scanning electron microscopy, differential scanning calorimeter and energy-dispersive X-ray spectroscopy. In the case of oligomers, they were also characterized by infrared spectroscopy, gel permeation chromatography and 1H NMR analyses. The adsorption properties of coated microspheres toward toxic metals showed maximum adsorption capacities of 309.32, 225.35 and 97.72 mg g−1 for lead, nickel and cadmium cations, respectively; which fitted very well with the Freundlich isotherm model. In a preliminary fixed-bed column study based on the removal of heavy metals by means of the coated microspheres showed that breakthrough curve for the Pb2+ presents the better fitting to the experimental data at times greater than 30 min and predicts the equilibrium at time greater than 160 min. Adsorption/desorption studies demonstrated that coated microspheres could be recovered using 0.05 M EDTA solution with a maximum recovery amount of heavy metals higher than 50%, which making them regenerable and reusable. These results suggest that coated stainless steel metallic hollow microspheres with oligomers obtained from PET waste are a potential system for the removal of heavy metal from contaminated effluents. [ABSTRACT FROM AUTHOR]

Rapid urbanization and economic growth are affecting an exceptional increase in the production of municipal solid waste (MSW), including packaging waste globally. Nations have a comparatively higher GDP incline to generate vast quantities of MSW. Forecasts appearance that the production of MSW through main metropolitan will increase from 1.3 and 2.2 billion tons, respectively in the year 2012 and 20251. The recycling of plastic/packaging waste materials to produced value-added material is an essential aspect for scientific research worldwide because the attenuation natural resources make a risk in future. Waste of MSW is frequently a high source of many essential materials for recycling such as plastic, glass, metal and paper. Active management of MSW can allow reclamation of essential materials of recycling and decreases of harmful impact on the environment. The waste categorization is a crucial step in MSW or many kinds of wastes, such as packaging/plastic waste management for materials recycling. Worldwide researchers have been vigorously discovering automatic categorization methods for efficiently handling of growing amounts of MSW. This review article summarizes growths in separation techniques, conversion for plastic/packaging waste in value-added products and its uses that have taken place in the area of source segregated MSW recycling, including plastic/packaging waste in the last decade. [ABSTRACT FROM AUTHOR]

Fired clay brickwork in buildings is prone to cracks and deterioration upon exposure to long-time acidic contamination and water absorption, hence decreasing the bearing capacity of masonry walls. As its contribution toward resolving this challenge, this study assessed the durability and morphological characteristics of high-strength performance bricks produced from a mixture of PET waste (PW) and foundry sand (FS). The PET waste bricks (PWBs) were produced through different proportioning (PW: FS) of 20%, 30%, and 40% of the dry mass of FS. The PWBs produced were tested for durability and compressive and tensile strengths and compared to fired clay bricks to evaluate their load-bearing capacity under compression and tension. Furthermore, scanning electron microscopy (SEM) tests were employed to analyze the morphological structure of the bricks. The test results revealed that the PWBs recorded an appreciable strength of 1.5–2 times that of fired clay bricks, and lower water absorption whilst retaining their ultimate strengths after complete immersion in water and acidic concentrations. The morphology of PWB possessed greater intercluster bonds on the surface compared to clay bricks. The findings demonstrate a reasonable methodological approach toward the production of masonry bricks using a mixture of PET waste and spent foundry sands.

The aim of this study involved the synthesis and characterization of polyurethane (PUR) foams obtained from poly(ethylene terephthalate) (PET) depolymerization products and two types of filling agents, namely fly ash and glass waste. The depolymerized PET-based products were obtained by zinc acetate-catalyzed glycolysis process in diethylene glycol (DEG) as a co-reactant. The resulting glycolysis products were contacted with methylene diphenyl diisocyanate, castor oil, and reinforcing agents. The resulting PUR specimens were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), EDX mapping, mechanical tests, and thermal analysis. The analysis confirmed that the best mechanical performances were registered by the specimens with the lowest concentration of filling agent, while the highest thermal resistance was achieved by the PUR foams with the highest concentration of reinforcing agent., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests., (© 2023 The Authors.)

The article describes the results of a study to determine the simultaneous effect of polyethylene terephthalate waste (PET) and polyethylene (PE) on the strength characteristics and bulk density of epoxy mortars. In these mortars, 9 wt.% of the polymer binder was replaced by glycolysate which was made from PET waste and propylene glycol. Additionally, 0–10 vol.% of the aggregate was substituted with PE agglomerate made from plastic bags waste, respectively. The modification of the composition of epoxy mortar has a special environmental and economic aspect. It also allows to protect natural sources of the aggregate, while reducing the amount of waste and reducing problems arising from the need to store them. The resulting composite has very good strength properties. With the substitution of 9 wt.% of resin and 5 vol.% of sand, a flexural strength of 35.7 MPa and a compressive strength of 101.1 MPa was obtained. The results of the microstructure study of the obtained mortars constitute a significant part of the paper.

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]

Composite materials from PET and red mud (RM) wastes were used as catalysts for environmental application such as the wastewater treatment. The PET-RM catalysts were obtained by a mechanical mixture of the residues followed by thermal treatment under an N2 atmosphere (300°C/1 h). An additional activation of the composites with CO2 was investigated (at 800–900°C) to reduce the red mud basicity. The CO2 activation affected the composites surface area and reduced their carbon content. XRD revealed that the haematite (α-Fe2O3) and maghemite/magnetite are the main iron oxides present in the composites. Mössbauer characterization indicated the formation of reduced iron species (Fe2+), highly reactive, after the composites heat treatment. The materials were very active catalysts for methylene blue (MB) and paracetamol (PRC) removal from aqueous solution. The catalytic activity revealed to be dependent on the surface area and mainly of the presence of reduced iron species in the catalysts. The MB removal reached 97% for both PET-RM 800/2 h and PET-RM 800/5 h, after 1 h of reaction. In the case of PRC, the highest removal was also obtained for PET-RM 800/2 h and PET-RM 800/5 h, of ≈25% and 40%, respectively. The contaminants removal mechanism likely occurred through combined adsorption and Fenton-like oxidation processes. [ABSTRACT FROM AUTHOR]

Oxygen augmented carbon adsorbent has been developed using polyethylene terephthalate (PET) waste by first carbonizing at different temperatures (500–800 °C) and then chemically activating using different ratios of KOH: PET (mass ratio 1 to 4). The textural characterization divulges the effect of activation in terms of the development of the high surface area and micropore volume of 1690 m2 g−1 and 0.78 cm3 g−1 respectively, for the optimum sample (PET-3-700). Elemental analysis of PET-3-700 illustrates the presence of 34.33% oxygen and XPS results confirmed the occurrence of oxygen moieties which enhance the basicity of the adsorbent and promote CO 2 capture. The CO 2 adsorption capacity of prepared carbons was determined thermogravimetrically under dynamic conditions, at different concentrations of CO 2 (6–100%) and temperatures. The maximum CO 2 uptake capacity of 2.31 mmol g−1 was exhibited by PET-3-700 at an adsorption temperature of 30 °C under 100% pure CO 2 flow. Four adsorption-desorption cycles corroborate almost complete regenerability of the prepared adsorbent. Adsorption kinetics at all adsorption conditions was described best by fractional order kinetic model. Freundlich isotherm fit indicates the surface of adsorbent being heterogeneous and low values of isosteric heat shows physisorption behavior of the process. Negative values of thermodynamic parameters indicate exothermic and feasible nature of adsorption process. Image 1 • Development of the carbon adsorbents from PET waste by carbonization followed by KOH activation. • PET-3-700 showed highest CO 2 uptake of 2.31 mmol g−1 at adsorption temperature of 30 °C. • Fractional order kinetic model best described the CO 2 adsorption process. • Four adsorption-desorption cycles performed on adsorbents exhibited almost complete regenerability. • Freundlich isotherm model best described the CO 2 adsorption isotherm. [ABSTRACT FROM AUTHOR]

This paper describes the preparation of O-enriched porous carbonaceous adsorbents derived from low cost, abundantly available polyethylene terephthalate (PET) waste with high carbon content by directly carbonising at different temperatures (500–800 °C) and then chemically activating using variable impregnation ratios of KOH to carbon. The prepared carbon adsorbents were characterized for their textural and surface chemical properties using nitrogen sorption, CHN, FTIR, XRD, SEM, HRTEM, and XPS techniques. Further, to assess their CO 2 adsorption-desorption performance under dynamic conditions, breakthrough experiments were conducted in a fixed-bed adsorption set up. Porous carbon obtained at 700 °C with KOH to carbon mass ratio of 3 (Act-3-700) exhibited best textural properties with BET surface area of 1690 m2g-1 and micropore volume of 0.78 cm3 g−1 and showed highest CO 2 uptake of 1.31 mmol g−1 at 30 °C and 12.5% CO 2 concentration. Four adsorption–desorption cycles establish the adsorbent's remarkable stability and regeneration. Furthermore, fractional order kinetic model explained the CO 2 adsorption kinetics and Freundlich isotherm showed superior fit with the adsorption equilibrium data suggesting heterogeneous nature of the adsorbent surface. Negative values of Gibbs free energy ΔG° and adsorption enthalpy ΔH° indicate the spontaneous and exothermic nature of adsorption process. Image 1 • Synthesis of the low cost adsorbents from PET waste via KOH activation. • Act-3-700 showed highest CO 2 uptake of 1.31 mmol g−1 at 30 °C. • The adsorption process followed fractional order kinetic model. • Adsorbents showed almost complete regenerability over four sorption cycles. • Freundlich isotherm model fitted best with the experimental data. [ABSTRACT FROM AUTHOR]

We report a robust synthesis of polymeric plasticiser from the post-consumer plastic waste, i.e. poly(ethylene terephthalate) (PET) and its subsequent use as plasticiser for preparation of nitrile rubber (NBR) and nitrile-PVC rubber blends. PET waste was depolymerised by alcoholysis with the help of 1-decanol. The obtained oligomeric plasticiser was characterised for its chemical structure using Fourier Transform Infrared Spectroscopy and Nuclear Magnetic Resonance. The prepared polymeric plasticiser was then used for the preparation of nitrile and nitrile-PVC blend rubber sheets. NBR and nitrile-PVC blend rubber sheets were also prepared by using dioctyl phthalate as plasticiser. The fabricated sheets were compared for their mechanical properties such as tensile strength, elongation at break, hardness. The effect of ageing on mechanical properties was also analysed. It was observed that the use of polymeric plasticiser resulted in significant improvement in tensile properties and ageing resistance. This eco-friendly synthesis of plasticiser offers its use for high-performance applications. [ABSTRACT FROM AUTHOR]

Abstract Waterborne castor oil-recycled polyol based polyurethane-silica nanocomposite adhesives (WPU) with polymer matrix and silica nanoparticles chemically bonded have been successfully prepared through a sol-gel process. A series of waterborne polyurethane adhesives with hard segment contents from 71.3 to 74.5 wt%, were synthesized using an isophorone diisocyanate, 2-bis(hydroxymethyl) propionic acid, recycled castor oil-based as soft segments and (3-aminopropyl)triethoxysilane (APTES) as chain extender. The depolymerized oligoester obtained from glycolysis of poly(ethylene terephthalate) (PET) waste using triethylene glycol (TEG), was transesterified with castor oil (CO) which resulted in the formation of hydroxyl-functional polyester polyol, with hydroxyl value of 414 mgKOH g−1. The molecular structures and mass of glycolyzed PET oligoesters, castor oil-based polyol and castor oil-based polyurethane-silica nanocomposite adhesives were estimated by Fourier transform infrared spectroscopy (FTIR) and gel permeation chromatography (GPC). The structure and properties of the resulting films were investigated by FTIR, wide angle X-ray diffraction measurement (XRD), thermogravimetry (TG) and differential scanning calorimetry (DSC). TG analysis indicated that APTES can improve the thermal stability of WPU. XRD showed that the crystallinity of WPU decreased with the increase alkoxysilane content. The extent of crosslinking was investigated to show a dependence on silica concentration, which increased the glass transition temperature and particle size of polyurethane nanocomposites with increasing alkoxysilane content due to the condensation of the alkoxysilane groups. The hardness, adhesion and gloss quality of the polyurethane films were also determined considering the effect of APTES content, so this paper confirmed the suitability of using these castor oil-based waterborne polyurethane-silica nanocomposites as new adhesive materials with high performance coatings materials. The experimental results reveal that the APTES and the hard segment content play a key role in controlling the structure and properties of the PU cast films based on castor oil-recycled polyols. [ABSTRACT FROM AUTHOR]

This study explored dog guardian behaviors and self-reported perceptions regarding the disposal of dog waste on Open Space and Mountain Parks (OSMP) lands in Boulder, Colorado, in an effort to increase compliance with proper disposal practices. We utilized direct observations of dog owners and their behaviors regarding pet waste, and separate self-reported surveys to examine dog owners' perceptions of waste disposal on OSMP lands. The Theory of Planned Behavior served as a framework to explore how dog owners' attitudes, norms, and perceived behavioral control might influence behavioral intentions, as well as self-reported current behavior, regarding the disposal of pet waste on OSMP lands. Finally, this study explored potential management techniques that may influence dog owners to properly dispose of waste on OSMP lands in the future. Data were collected across 10 sites, for total of n=541 observations and n=386 surveys. Canine defecation and human behavioral response occurred n=102 times during the n=541 observations, and overall 73.5% of dog owners properly (i.e., bag waste and immediately take all bags) disposed of waste. Without considering immediate disposal in a trash or compost receptacle, owners with dogs on-leash were significantly more likely to bag their pets' waste than owners with dogs off-leash. When both bagging waste and immediately disposing of waste in a waste or compost receptacle are considered, owners with dogs on-leash had a tendency (~11% more likely) to bag and immediately take pet waste for disposal. Perceived behavioral control was the construct that most significantly correlated with behavioral intent regarding proper disposal of dog waste. Many respondents reported that additional trash or compost receptacles and bag dispensers along trails would make them more likely to follow recommended practices related to the disposal of pet waste in the future. These results suggest that management should consider the following: designating more on-leash-only sites because compliance is substantially higher when dogs are on-leash; establishing on-leash segments along the first quarter of a mile from all trailheads; installing an additional trash and/or compost receptacle and bag dispenser, specifically one quarter of a mile from the trailheads. Pairing these with educational strategies that inform pet owners to not leave bagged pet waste for later disposal, while highlighting the ease of immediately bagging waste and carrying it to a trash or compost receptacle may further increase compliance. [ABSTRACT FROM AUTHOR]

This work is aimed at electrochemical decolorization of real waste liquid which obtained in the PET depolymerization process. Firstly, PET fabrics were glycolysized by utilizing excess ethylene glycol (EG). Then, the glycolysis product was mixed with water and purified through repeated crystallization to get bis(2-hydroxyethyl) terephthalate (BHET) crystal. At last, the waste liquid of the depolymerization process was electrochemical decolorized by utilizing chitosan/Fe3O4 nanoparticles as the dispersed electrodes under a DC voltage. The UV-Vis absorptions at 338, 531, and 635 nm which were due to the dyes in the waste liquid decreased with the electrolysis time. In contrast, slight change of absorption of EG (at 322 nm) indicated that EG was not destroyed in the electrolytic process. The variation of color removal efficiency with dosage of chitosan/Fe3O4 nanoparticles, applied voltage, concentration of electrolyte, pH and electrolytic time were investigated. The max color removal efficiency was 87.24%. PET fabrics were depolymerized by using the decolorized waste liquid or mixture of decolorized waste liquid and EG (1:1 v/v), and the yields of BHET were 72.3% and 76.6%, respectively. The products were BHET without dyes which were confirmed by DSC and FTIR spectroscopy.Graphical abstract [ABSTRACT FROM AUTHOR]

Plastic production has increased by almost 200-fold annually from 2 million metric tons per year in 1950s to 359 million metric tons in 2018. With this rapidly increasing production, plastic pollution has become one of the most demanding environmental issues and tremendous efforts have been initiated by the research community for its disposal. In this present study, we reported for the first time, a biomass-waste-derived heterogeneous catalyst prepared from waste orange peel for the depolymerisation of poly(ethylene terephthalate) (PET) to its monomer, bis(2-hydroxyethyl terephthalate) (BHET). The prepared orange peel ash (OPA) catalyst was well-characterised using techniques such as IR, inductively coupled plasma (ICP)-OES (Optical Emission Spectrometry), XRD, X-ray fluorescence (XRF), SEM, energy-dispersive X-ray spectroscopy (EDX), TEM, BET (Brunauer-Emmett-Teller) and TGA. The catalyst was found to be composed of basic sites, high surface area, and a notable type-IV N2 adsorption–desorption isotherm indicating the mesoporous nature of the catalyst, which might have eventually enhanced the rate of the reaction as well as the yield of the product. The catalyst completely depolymerises PET within 90 min, producing 79% of recrystallised BHET. The ability of reusing the catalysts for 5 consecutive runs without significant depreciation in the catalytic activity and its eco- and environmental-friendliness endorses this protocol as a greener route for PET recycling.

The developed process worked well for all kinds of PET waste and mixed PET waste for the production of purified hydrogen gas for direct application in fuel cells. Keywords: Hydrogen production; PET waste; Ruthenium; Aqueous condition; Low temperature EN Hydrogen production PET waste Ruthenium Aqueous condition Low temperature 1 1 1 09/25/23 20230922 NES 230922 B The Cover Feature b represents the one-pot process for hydrogen production over the catalyst with simultaneous depolymerization of PET to terephthalic acid, which can further be used to synthesise PET. Cover Feature: One-pot Upcycling of Waste Plastics for Selective Hydrogen Production at Low-Temperature (ChemCatChem 18/2023). [Extracted from the article]

The widespread use of polyethylene terephthalate (PET) in the packaging industry has led to the discharge of huge amounts of such waste into the environment and is an important source of pollution. Moreover, because the degradation of PET waste requires a very long time (over 180 years), the recycling of this waste is the only solution to reduce environmental pollution in this case. The solution proposed in this study, is the transformation of PET waste into granular adsorbent materials by functionalization with different phenolic compounds (phenol, p-chlor-phenol, and hydroxyquinone), and then their use as adsorbent materials for removing metal ions (ex. Cu(II) ions) from aqueous solutions. The functionalization of PET waste was done with different amounts (2–8 g) of each phenolic compound. The adsorption capacity of obtained materials was tested at different initial Cu(II) ions concentrations, in batch systems, at room temperature (20 ± 1 °C). The experimental results have shown that the adsorbent material obtained by the functionalization of PET waste with 8 g of phenol has the best adsorptive performances (q = 12.80 mg g−1) at low initial concentrations of Cu(II) ions, while the adsorbent material obtained by the functionalization of PET waste with 2 g of hydroxyquinone is more efficient in removal of high concentrations of Cu(II) ions (q = 61.73 mg g−1). The experimental isotherms were modeled using Langmuir and Freundlich isotherm models, to highlight the adsorptive performances of these new adsorbents and their potential applicability in environmental decontamination processes.

Polyethylene terephthalate (PET) bottle is one of the common plastic wastes existed in the municipal solid waste in Malaysia. One alternative to solve the abundant of PET wastes is chemical recycling of the wastes to produce a value added product. This technology not only can decrease the PET wastes in landfill sites but also can produce many useful recycled PET products. Bis(2-hydroxyethyl) terephthalate (BHET) obtained from glycolysis reaction of PET waste was purified using crystallization process. The hot distilled water was added to glycolysis product followed by cooling and filtration to extract BHET in white solid form from the product. The effect of three operating conditions namely crystallization time, crystallization temperatures and amount of distilled water used to the yield of crystallization process were investigated. The purity of crystallization products were analyzed using HPLC and DSC. The optimum conditions of 3 hours crystallization time, 2 °C crystallization temperature and 5:1 mass ratio of distilled water used to glycolize solid gave the highest yield and purity of the crystallization process. © 2015 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0)

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]

Resin concretes belong to a small group of building materials which, besides high strength parameters, also have a very good chemical resistance. This is confirmed by the studies carried out by various research institutions around the world. However, there is little data on the behaviour of composite resin exposed to corrosive solutions for an extended period of time. This article presents the results of the research on weight changes in samples of epoxy mortar modified with poly(ethylene terephthalate) glycolysates, immersed for 5 years in four different aggressive media i.e. 10% aqueous solutions of sulphuric and nitric acids, sodium hydroxide, and sodium chloride. The actual average weight changes obtained were compared with the data calculated on the basis of the regression functions fitted to the data recorded after 3.5 years of exposure. This allowed verification of the model selection correctness and evaluation of the effectiveness of the fitted regression curve. In the case of aqueous sodium hydroxide and sodium chloride solutions, it can be assumed that the logarithmic model describes weight changes well. It was observed that the weight of the samples exposed to NaCl solutions and NaOH stabilizes over prolonged monitoring time and reaches a plateau. However, the weight changes in mortar samples immersed for 5 years in aqueous solution of sulphuric and nitric acids quite significantly differ from the data calculated on the basis of the trend line fitted to the results of the tests carried out after 3.5 years of exposure. It seems that the better solution in this case is the selection of an exponential model. In addition, placing the logarithmic trendlines for all corrosive media together on a chart allows to note which of the solutions is the most aggressive. It was found that after 5 years of immersion in aqueous solutions of acids, mortar samples became brittle, and the observation of their fractures confirmed the weakness of the connection on the resin/aggregate phase boundary. Changes in the appearance of the samples were also noted, namely the surface of samples submerged in a solution of nitric acid strongly yellowed, and those treated with sulphuric acid were tarnished. [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]

In this study, easy and rapid adsorption of Orange G dye from aqueous solution using PET (polyethylene terephthalate) waste as low-cost adsorbent was examined. The optimal values of most important experimental parameters (initial solution pH, adsorbent dose and contact time) were established, in batch experiments, at room temperature (20°C ± 1°C). The kinetics of adsorption process follows the pseudo-second order kinetic model, and the Langmuir isotherm model provides the best fitting for the adsorption of Orange G dye onto PET waste. The maximum adsorption capacity, calculated in this case, was 6.9961 mg/g. Unfortunately, this value is quite small, and therefore an activation treatment of PET waste is necessary. The activation of PET waste with NaOH solution (4 N, 48 h) determines the increase of maximum adsorption capacity with 33.48%, indicating the formation of new active sites on adsorbent surface, probably due to the hydrolysis of some ester groups from superficial polymer chains. The adsorption capacities obtained for the Orange G adsorption onto activated PET waste from five different water samples does not differ significantly, which highlight the potential applicability of this adsorbent in the treatment of industrial effluents. [ABSTRACT FROM AUTHOR]

Chemical recycling of polyethylene terephthalate (PET) to produce terephthalic acid (TPA) was studied using in situ hydrolysis with sodium methoxide in methanol and dimethyl sulfoxide (DMSO) as solvent under microwave irradiation. The microwave-assisted reaction was carried out at different temperatures, and reaction time between 5 to 30 min. High degrees of depolymerization were examined at temperature near 70°C at microwave power 300 W. The reaction was carried out in a sealed microwave reactor in which the time and temperature were controlled and recorded. The products were mainly monomers such as TPA and ethylene glycol (EG) which were isolated and purified for further analysis. Monomethyl terephthalate, dimethyl terephthalate, and terephthalic acid were formed initially then converted to TPA as a single monomer product. Purified, TPA was analyzed and identified by NMR, TGA, DSC and FTIR. It was observed that the reaction greatly depends on the amount of sodium methoxide, the volume of methanol and DMSO used, the reaction time, and temperature. Compared to conventional heating methods, the time needed to achieve complete degradation of PET was significantly reduced to 5 min by using microwave irradiation and sodium methoxide catalyst. This has led to substantial saving in energy and cost supporting the conclusion that this proposed recycling process is very beneficial for the recycling of PET wastes. [ABSTRACT FROM AUTHOR]

The fire behavior and thermal stability of unsaturated polyester prepared from recycled poly(ethylene terephthalate) (RUP) in the present of two phosphorus-nitrogen flame retardants (FRs) including ammonium polyphosphate (APP) and melamine polyphosphate (MPP) have been investigated. The effectiveness of FRs on the fire proofing of material was test by UL-94 vertical classification and limiting oxygen index (LOI). The obtained data showed that the fire retardancy and thermal stability were remarkably enhanced with addition of FRs. The best grade of UL-94V standard, V-0 ranking was attained as loading of 25 wt% of APP or 30 wt% of MPP. LOI significantly were enhanced from 20 to 36%. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and Scanning electron microscope (SEM) were applied to determine the structure and morphology of char layers of RUP and RUP/FR mixtures. Thermogravimetric analysis (TGA) method was applied to investigate thermal stability of neat RUP, FRs, and RUP/FR and to evaluate kinetic parameters of the decomposition of RUP/FR. The mechanism of action of FRs, schemes for the possible decomposition mechanism RUP and FRs, and the cooperation of matrix and additives were also discussed. [ABSTRACT FROM AUTHOR]

The present work is aimed on the study of degradation of poly(ethylene terephthalate- co-lactate) copolyesters, prepared by chemical modification of PET waste beverage bottles using l-lactic acid, under laboratory (bioreactor) and natural (Central Composting Plant in Brno, Czech Republic) composting conditions. The structure of solid residues after degradation was analyzed by IR, NMR, thermogravimetric (TGA) methods, and size exclusion chromatography in chloroform and the residues rich on aromatic units were analyzed in CHCl/HFIP solutions. Sample with 57 mol% of aliphatic units showed the highest degree of degradation with mass loss of about 90% independently of composting conditions. The samples with 57 and 60 mol% of aromatic units reached 68 and 51% degradation in the compost pile and only 39 and 5% in laboratory bioreactor. Gravimetric analysis along with molar mass distribution measurement showed that laboratory-level composting study provides more consistent and defined results. However, it should be accompanied with tests performed under real conditions for the purpose of biodegradability evaluation of polymeric materials with varying composition. [ABSTRACT FROM AUTHOR]

This paper describes results of testing and analysis of reinforced concrete beams contained PET waste particles. The beams were lightly reinforced with steel rebar and designed to fail in flexure. Test results showed that as a result of using PET waste shredded particles in concrete as sand replacement there is a reduction in compressive strength in the range of 12–21%. Properties of stiffness and mode of failure for recycled PET waste reinforced concrete are almost identical to those of normal beams. Ultimate load capacity was reduced moderately, and load-deflection response was slightly changed as a result of using PET waste particles up to 15%. Regression analysis was made for developing equations for calculating compressive strength and maximum compressive strain of concrete containing PET waste. Later, analysis was made for calculating ultimate moment capacity of under reinforced concrete section. Making a comparison with the test data showed that the predictions of moment capacity are accurate. The difference between calculated moment based on test and that based on calculated compressive strength was found to be not important. It is concluded that up to 15% well graded PET waste can be added safely to produce this type of recycled reinforced concrete beams for structural applications. [ABSTRACT FROM AUTHOR]

Properties of concrete containing PET plastic wastes are now well understood as a result of many experimental tests. Aspects of structural design and analysis of concrete members made from concrete containing PET waste need accurate equations for mechanical properties. In this paper, available data on mechanical properties of normal strength concrete containing PET waste were collected, analyzed, and equations were developed for calculating elastic modulus, splitting and flexural tensile strengths. Results of analysis indicate that, in general, there is a good correlation between the three properties and compressive strength of concrete containing PET plastic waste. The proposed equations were found to be safe and accurate, and can apply for recycled concrete containing different types of plastic waste other than shredded PET waste. The models proposed for mechanical properties can be utilized in the analysis and design of those structural members made from recycled concrete containing PET waste and some other plastic wastes. [ABSTRACT FROM AUTHOR]

The main objective of this study was to investigate the potential utilization of polyethylene terephthalate PET waste in cementitious matrix, as substituent to cement, to develop lightweight construction materials and for preventing chemical attacks or repairing various reinforced concrete structures. Composites containing different amounts of PET particles, as partial replacement to cement by weight, were characterized by destructive and non-destructive testing. So, the thermal conductivity, ultrasonic pulse velocity (UPV) and sorptivity coefficients of composite made up of mixtures of PET polymer were measured; the adverse environmental conditions are simulated by using various acid solutions. The corrosion process was monitored by measuring the mass loss and compressive strength for different periods. The experimental investigation revealed that the addition of PET particles reduces the UPV; furthermore, thermal conductivity and sorptivity of the composites have been decreased. So, the decrease of the sorptivity-value is favorable to the durability of the specimen structures. On behalf of the resistance to aggressive environments, it was found that the course of action of acid attack is dependent on the type of acid and solubility of the calcium salt formed. The presence of PET was found to lower the detrimental effect of acids on composite. Scanning electron microscope (SEM), X-ray diffraction and FT-IR analyses were used to better understand the cement hydration products of the deteriorated mortars. In this way, the obtained PET-mortar composites would appear to be low-cost materials which would contribute to resolving some of the solid waste problems in addition to conserving energy. [ABSTRACT FROM AUTHOR]

Waste polyethylene terephthalate (PET) bottles were collected, cleaned and then depolymerized by glycolysis with neopentyl glycol (NPG) and dipropylene glycol (DPG), in the presence of N-butyl titanate catalyst. The product, named glycolyzed oligoesters, obtained through the depolymerization, were employed respectively in hard segment and soft segment in the synthesis of novel waterborne polyurethane dispersions (PUDs) via a simple and environmentally benign process. In addition, a polyurethane dispersion without glycolyzed oligoesters was synthesized as a comparison. The bulk structure of PET glycolyzed oligoesters and PUDs films were characterized by Fourier transform infrared spectroscopy (FT-IR), H-nuclear magnetic resonance ( 1 H NMR) and Gel permeation chromatography (GPC). The results illustrated that glycolyzed oligoesters were successfully introduced into the hard and soft segment of the polyurethanes. Furthermore, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were used to investigate the thermal properties of the PET glycolyzed oligoesters and PUDs films. The results showed that the thermal resistance of waterborne polyurethanes obtained with glycolyzed oligoesters increased due to lower degrees of phase separation. X-ray diffraction indicated that all synthesized polyurethanes exhibited reduced degrees of orientation. Due to the balance between hard-/soft-segment of the waterborne polyurethane dispersions, the formulations containing glycolyzed oligoesters within the hard segment sections of the polyurethanes provided the best performance. [ABSTRACT FROM AUTHOR]

Medium oil alkyd resins based on the glycolyzed PET waste and different generations of aliphatic hyperbranched polyesters with linseed and sunflower oil fatty acids, which are of interest to the coating industry, were investigated. Different resin compositions were synthesized and characterized by IR and 1 H NMR spectroscopy. The effect of oil fatty acid type, glycolyzed products, functionality of the polyols on thermal and film performance properties was studied. The onset of decomposition of all samples displayed at values above 200 °C which render them suitable for the processing requirements of most conventional coating applications. All films had good adhesion, bending, impact and ductility. The gloss and hardness increased with increasing the degree of branching and consequently, the molecular weight in the resin backbone. The presence of G3 as polyol enhanced the thermal stability and film properties of coatings. [ABSTRACT FROM AUTHOR]

The need for the environmental preservation and the tendency of the lack of natural resources makes civil construction to acquire new concepts and technical solutions focused on sustainability. In this context, the recycling and reuse of the residues by incorporating them into soil-cement bricks represent an alternative in full harmony with the guidelines of sustainable development, attributing them to the condition of noble material, rather than simply throwing them into nature. In this paper, studies and results of laboratory tests are presented, which the objective was to evaluate the behavior of soil-cement bricks by incorporating levels of grinded PET residue for the use in the civil construction. Therefore, characterization tests of soil in Caruaru-PE region and the incorporation of PET waste in the proportions of 5, 8 and 11% were carried out. The standard soil-cement mass trace was 1:10. To perform the compression strength test, a method was adapted to promote the best compression of the particles in test samples of 50mmX100mm. It was observed that the incorporation of the PET residue improved the average compressive strength for all percentages evaluated, where the 11% content promoted an increase of 163.15% compared to the standard trace. The water absorption for all the studied mixtures was in accordance with the current standards. In view of the above, the use of PET residue can be viable in the manufacture of soil-cement bricks, being used in an intelligent and beneficial way to society. [ABSTRACT FROM AUTHOR]

Domestic waste is often burned either as fuel for winter heating or in open areas, simply to get rid of waste. Polyethylene terephthalate (PET) represents an important component of plastics usage as well as of plastic waste produced. While most studies attempt to characterize environmental risk of open burning of mixed household waste, present work evaluates chemical and ecotoxicological parameters of particulate matter (PM) produced during controlled burning of PET samples. In the PM 10 samples, polycyclic aromatic hydrocarbon and heavy metal concentrations were measured, ecotoxicity was evaluated using the kinetic Vibrio fischeri bioassay. Both chemical composition and ecotoxicity of the 4 samples showed significant correlation, regardless of the colored or colorless nature of the original PET sample. Antimony was found in considerable concentrations, in the range of 6.93–16.9 mg/kg. PAHs profiles of the samples were very similar, showing the dominance of 4-and 5-ring PAHs, including carcinogenic benzo(a)pyrene. • Ecotoxicity of PM generated during controlled burning of waste PET was evaluated. • 4- and 5-ring PAHs were dominant in the particles. • Particles contained high concentration of antimony. • Colored and colorless PET samples showed similar chemical composition and ecotoxicity. [ABSTRACT FROM AUTHOR]

The possibility to use poly(ethylene terephthalate) (PET) bottles production waste as raw material for compositions with high adhesion ability has been investigated. PET waste was glycolyzed with polypropylene glycol and three kinds of oligoesters were formed after depolymerization reaction. The polydispersity of product formed was 1.05. The possibilities to use PET glycolysis products – oligoesters for epoxy resin and polyurethanes were studied. Two-step reaction of oligoesters with epichlorohydrin was chosen for epoxy resin synthesis, while glycolyzed PET reaction with aliphatic isocyanate was used for polyurethane synthesis. The structure and properties of the obtained polymers were investigated. DOI: http://dx.doi.org/10.5755/j01.ms.19.3.5237

The building industry is facing the challenge of satisfying a growing demand for housing spaces that can be mitigated by the use of construction materials manufactured with industrial by-products that allow the production of low-cost housing with a low environmental impact. In this research, an alternative building system to manufacture lightweight masonry blocks with polyethylene terephthalate (PET) bottles and fiber-reinforced panels using binary mixture (Portland cement and fly ash), was studied. This building system was tested under compressive and flexural loads until failure. The average design compressive strengths of concrete blocks for w/c ratios of 0.78 and 1.1 were fp = 1.9 and 1.2 MPa respectively, these results were similar to those typical masonry in accordance with the design and construction standards. On the other hand, the flexural strength, the modulus of elasticity and the stiffness on mid span of the fiber-reinforced concrete panels were improved with adding 20% of fly ash to both w/c ratios, mainly at 120 days. The experimental results obtained show that those building elements are viable alternatives with mechanical properties comparable to traditional building systems, besides the reduction of the environmental impact due to the incorporation of industrial waste materials. Â