Polyethylene Terephthalate Polymer Research Articles

On the Non-Catalytic Role of Lytic Polysaccharide Monooxygenases in Boosting the Action of PETases on PET Polymers.

Synthetic polymers are resistant to biological attack, resulting in their long-term accumulation in landfills and in natural aquatic and terrestrial habitats. Lytic polysaccharide monooxygenases (LPMOs) are enzymes which oxidatively cleave the polysaccharide chains in recalcitrant polysaccharides such as cellulose. It has been widely hypothesised that LPMOs could be used to aid in the enzymatic breakdown of synthetic polymers. Herein, through the use of biochemical assays, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) we show that LPMOs can bind to polyethylene terephthalate (PET), and - in doing so - the hydrophobic surface of PET becomes more hydrophilic such that product release is boosted by subsequent treatment with classical PETases. The boosting effect is however, only observed in reactions when the LPMO and the PETase are added sequentially rather than simultaneously to the PET. Moreover, the same boosting effect is also seen when a catalytically-inactive mutant of LPMO is used, showing that the principal means by which AA9 LPMOs boost the degradation of synthetic polymers is through their role as a "hydrophobin" rather than as an oxygenase. Indeed, in accord with this role of LPMOs, we further show that this effect can be extended to other ostensibly 'non-catalytic' proteins beyond LPMOs, such as bovine serum albumin and lactate dehydrogenase.

Microplastics at Environmentally Relevant Concentrations Had Minimal Impacts on Pelagic Zooplankton Communities in a Large In-Lake Mesocosm Experiment.

To assess the potential risks of contemporary levels of plastic pollution in freshwater ecosystems, a large-scale experiment was conducted over 10 weeks in a boreal lake at the IISD-Experimental Lakes Area (Ontario, Canada). Fragments of common polymers (polyethylene, polystyrene, and polyethylene terephthalate), each with distinct colors and buoyancies, were added as a single pulse to seven in-lake mesocosms in equal contributions in a range of environmentally relevant nominal concentrations (6-29,240 particles/L). Two additional mesocosms with no added microplastics were used as controls. Zooplankton ingested low levels of microplastics (mean of 0.06 particles/individual ± SD 0.07) and generally their total abundance and community composition were not negatively impacted. Temporary changes were however observed; total zooplankton abundance and abundance of calanoid copepods were temporarily stimulated by increasing nominal microplastic concentrations, and modest, short-term reductions in egg production of the cyclopoid copepod Tropocyclops extensus and abundance of copepod nauplii occurred. Collectively, these results suggest that microplastics could have complex impacts on zooplankton communities, stimulating some species while negatively impacting others.

POLYETHYLENE TEREPHTHALATE (PET) COATED WITH CHITOSAN AND CYCLOSPORINE A LAYERS AS A POTENTIAL STENT MATERIAL AND DRUG-DELIVERY SYSTEM

The aim of this paper was to design, prepare and characterise chitosan (Ch) and cyclosporine A (CsA) mixed films deposited on a plasma-activated polyethylene terephthalate (PET) polymer surface to be used as a cover for implantable blood vessel stents. The PET polymer coated with Ch and CsA layers was immersed in simulated body fluid (SBF) to examine how the obtained layers can behave in the environment of human body fluids. Time-of-flight secondary ion mass spectrometry was employed to determine the chemical composition of the deposited films and to analyse the spatial distribution of molecules on the PET surface. The results showed the controlled release of CsA from the chitosan matrix. It can be concluded that the modification of the PET polymer with layers of chitosan and CsA has great application potential in the tissue engineering as a biocompatible stent of blood vessels with therapeutic properties.

Structural insights into polyethylene terephthalate (PET)-degrading archaeal lipase enzyme: An insilico approach

Biodegradation of plastic is the most eco-friendly degradation process conferred by various microbial enzymes, especially the lipase enzymes. The lipase enzymes depict a broad substrate range, high regio/stereoselectivity, and stability in organic solvents. However, enhancing the catalytic activity of lipases for industrial production remains a challenge, predominantly due to the need for their extensive mechanistic characterization. Here, we employed a multidisciplinary approach to illustrate the comprehensive physiochemical and mechanical properties of 102 lipase sequences from six different groups of plastic-degrading microorganisms. Molecular docking-based evaluation of the binding efficiencies of selected lipases with the most common plastic polymers- polyurethane (PUR) and polyethylene terephthalate (PET), revealed that the archaeal lipase had the lowest binding energy of −7.1 kcal/mol with PET. Remarkably, the molecular dynamic simulation studies (up to 100 ns) and very low RMSD (0.3 nm) and RMSF (0.25 nm) values further ascertained the stability of archaeal lipase after binding with PET polymer. Further, a 2.19 nm radius of gyration (Rg) within 100 ns simulation time, binding free energy ΔGTOTAL with −24.36 kcal/mol and entropy factor -TΔS 7.65 kcal/mol also indicated strong binding of archaeal lipase with PET polymer. The mechanistic exploration of archaeal lipase yielded valuable insights into its effective binding with PET polymer, paving the way for future lipase enzyme engineering and harnessing its industrial potential for plastic biodegradation.

Static and dynamic analysis of polyethylene terephthalate foam core and different natural fiber-reinforced laminated composite-based sandwich plates through experimental and numerical simulation

This study explores the flexural behavior and free vibration analysis of sandwich plates including natural fiber-reinforced polymer composite faces and Polyethylene Terephthalate (PET) foam cores under a range of edge situations. ABAQUS is used to do numerical simulations with three-dimensional solid elements (C3D8R). To ascertain the natural frequencies of the plates, experimental procedures such as impact hammer testing and Fast Fourier Transform (FFT) analysis are carried out. The inference of different geometrical parameters on the natural frequencies is investigated through numerical simulation in ABAQUS. The study gives brief outlines regarding the sandwich plates for different engineering applications.

Tracking and risk assessment of microplastics in a wastewater treatment plant

AbstractToday, microplastics have become one of the most important environmental concerns. Wastewater treatment plants are a major source of microplastics in the environment. The aim of this study is to track and assess the risk of microplastics in a wastewater treatment plant. Samples were taken from different units of sewage treatment plants in the spring and winter. Microplastics were separated using sieves and density‐based methods. Analysis revealed a higher abundance of microplastics in spring. The highest amount of microplastic removal was in the disinfection and secondary sedimentation units in the winter season. Fragments are the most common shape. Poly Ethylene Terephthalate (PET) polymers were most prevalent. Black was the most common colour. Poly Ethylene (PE), PET and poly Amide (PA) polymers posed the highest risk, according to calculations. One of the most important ways to prevent microplastics from entering water sources is to reduce the consumption of plastic materials, recycle plastic waste and remove microplastics from the wastewater treatment process.

Development and application of a novel extraction protocol for the monitoring of microplastic contamination in widely consumed ruminant feeds

Plastics and, in particular, microplastics (MPs) (< 5 mm) are emerging environmental pollutants responsible for interconnected risks to environmental, human, and animal health. The livestock sector is highly affected by these contaminants, with 50–60 % of the foreign bodies found in slaughtered domestic cattle being recognized as plastic-based materials. Additionally, microplastics were recently detected inside ruminant bodies and in their feces. MPs presence in ruminants could be explained by the intensive usage of plastic materials on farms, in particular to store feeds (i.e. to cover horizontal silos and to wrap hay bales). Although feed could be one of the main sources of plastics, especially of microplastics, a specific protocol to detect them in ruminant feeds is not actually present. Hence, the aim of this study was to optimize a specific protocol for the extraction, quantification, and identification of five microplastic polymers (high-density polyethylene, low-density polyethylene, polyamide fibers/particles, polyethylene terephthalate and polystyrene) from feeds typically used in ruminant diets (corn silage, hay, high protein feedstuff and total mixed ration). Several combinations of Fenton reactions and KOH digestion were tested. The final extraction protocol involved a KOH digestion (60 °C for 24 h), followed by two/three cycles of Fenton reactions. The extraction recoveries were of 100 % for high-density, low-density polyethylene, polyamide particles, and polystyrene and higher than 85 % for polyethylene terephthalate and polyamide fibers. Finally, the optimized protocol was successfully applied in the extraction of microplastics from real feed samples. All the feeds contained microplastics, particularly polyethylene, thus confirming the exposure of ruminants to MPs.

Understanding the Ecological Robustness and Adaptability of the Gut Microbiome in Plastic-Degrading Superworms (Zophobas atratus) in Response to Microplastics and Antibiotics.

Recent discoveries indicate that several insect larvae are capable of ingesting and biodegrading plastics rapidly and symbiotically, but the ecological adaptability of the larval gut microbiome to microplastics (MPs) remains unclear. Here, we described the gut microbiome assemblage and MP biodegradation of superworms (Zophobas atratus larvae) fed MPs of five major petroleum-based polymers (polyethylene, polypropylene, polystyrene, polyvinyl chloride, and polyethylene terephthalate) and antibiotics. The shift of molecular weight distribution, characteristic peaks of C═O, and metabolic intermediates of residual polymers in egested frass proved depolymerization and biodegradation of all MPs tested in the larval intestines, even under antibiotic suppression. Superworms showed a wide adaptation to the digestion of the five polymer MPs. Antibiotic suppression negatively influenced the survival rate and plastic depolymerization patterns. The larval gut microbiomes differed from those fed MPs and antibiotics, indicating that antibiotic supplementation substantially shaped the gut microbiome composition. The larval gut microbiomes fed MPs had higher network complexity and stability than those fed MPs and antibiotics, suggesting that the ecological robustness of the gut microbiomes ensured the functional adaptability of larvae to different MPs. In addition, Mantel's test indicated that the gut microbiome assemblage was obviously related to the polymer type, the plastic degradability, antibiotic stress, and larval survival rate. This finding provided novel insights into the self-adaptation of the gut microbiome of superworms in response to different MPs.

Ultrasonic-assisted alkali hydrolysis of polyethylene terephthalate fabric and its effect on the microstructure and dyeing properties of fibers

Abstract In this study, ultrasound energy was applied to assist the alkali hydrolysis of polyethylene terephthalate (PET) fabric, and then, the results were compared with those of the mechanical oscillating method, which was used as the control. The effects of various factors such as the sodium hydroxide concentration, the dosage of dodecyl dimethyl benzyl ammonium chloride (DDBAC), and the frequency on the weight loss of the PET fabrics were systematically investigated. The surface appearance and microstructures of the treated fibers with different methods were analyzed using a scanning electron microscope and X-ray diffraction, respectively. The results showed that DDBAC played a prominent accelerating role in the hydrolysis of the PET polymer, and the frequency had a great influence on the weight loss of the PET fabric. Ultrasound with a frequency of 60 kHz showed a similar decomposition rate as the control, resulting in similar weight loss, which was the highest value among the three frequencies (20, 60, and 80 kHz). In addition, the application of ultrasonic energy led to more pits on the fiber surface, a smaller average grain size, and decreased crystallinity of the treated fibers, while the mechanical oscillating method resulted in slightly increased crystallinity. By comparing the K/S value of the dyed fabrics with two commercial disperse dyes, we found that the treatment method had no obvious correlation with the color depth of the treated fabric.

Structural and sound absorption properties of polyethylene terephthalate (PET) and recycled polyethylene terephthalate (r-PET) nanofibers

Sound-absorbing materials are used to reduce noise pollution since noise is one of the important environmental factors affecting human health. Due to their high porosity and large specific surface area, nanofibers can be preferred as a better sound absorption material. In this study, nanofiber-based sound-absorbing materials are produced using polyethylene terephthalate (PET) and recycled polyethylene terephthalate (r-PET) in the electrospinning method in order to obtain a thin and high-sound absorbing material. Another objective of this study is to investigate the performance of r-PET compared to PET from the sound absorbing properties points of view to contribute sustainability which is one of the most important issues of today. For these purposes, solutions of three different concentrations (10%, 15% and 20% owf) were prepared by dissolving PET and r-PET polymers in trifluoroacetic acid (TFA):dichloromethane (DCM) solvent mixture. It will also be possible to help sustainability issues by reducing environmental pollution and raw material costs by using r-PET. Samples were electrospun on a polypropylene based nonwoven structure using solutions at different flow rates (0.1-0.3-0.5 ml/h) and needle tip-collector distances (4–8 cm). The fiber diameter, thickness, bulk density, porosity and pore size properties of the produced samples were investigated. The sound absorption coefficient (SAC) was measured with a dual microphone impedance tube device. The relationship between the structural properties of the samples and the SAC was evaluated. SAC decreased with increasing fiber diameter, bulk density, pore size and increased with high porosity. These values were compared with different sound absorbing materials which are commonly used. According to the results, the developed nanofiber-based material with a 0.3 mm thickness has high SAC values compared to conventional sound absorbing materials with 10–16 mm thickness values, especially in middle frequency levels. Recycled polymer may be preferred when PET and r-PET nanofibers show similar results.

Sustainable strategies towards better utilization of synthetic polymers.

The abstract provides an overview of a study focused on analyzing diverse strategies to achieve sustainable utilization of synthetic polymers through effective waste management. The escalating global consumption of synthetic polymers has precipitated a concerning increase in plastic waste and environmental degradation. To address this challenge, novel materials with specified application goals, such as engineered plastic, have been developed and are intended for recycling and reuse. Despite the reuse and recycling, when plastic gets disposed into the environment, the degradation properties of plastics render a direct disposal hazard, posing a significant environmental threat. To mitigate these issues, the concept of replacing specific monomers of engineered synthetic plastics with bio-alternatives or blending them with other polymers to enhance sustainability and environmental compatibility has emerged. In this study, Acrylonitrile Butadiene Styrene (ABS) plastic is the focal material, and three distinct investigations were conducted. First, replacing ABS plastic's butadiene monomer with natural rubber was explored for its properties and environmental impact. Second, ABS plastic was blended with virgin, recycled, and bio-alternatives of PET (polyethylene terephthalate) and PVC (polyvinyl chloride) polymers. Lastly, recycled ABS blended with recycled PET and PVC was analyzed for mechanical properties. Comparative assessments of these blends were made based on mechanical properties, carbon emissions, and cost-effectiveness. The study determined that the r-ABS/r-PVC (recycled) blend exhibited the most favorable characteristics for practical application.

XPS guide for insulators: Electron flood gun operation and optimization, surface charging, controlled charging, differential charging, useful FWHMs, problems and solutions, and advice

Current day x-ray photoelectron spectroscopy (XPS) instrument makers have made significant advances in charge compensation systems over the last 20 years, which makes it easier to analyze insulators, but samples still have many differences in chemistry, dielectric properties, sizes, surface roughness, etc. that force instrument operators to tweak flood gun settings if they want or need to obtain high quality chemical state spectra that provide the most information. This guide teaches which flood gun variables to check, and how to optimize electron flood gun settings by presenting high energy resolution, chemical state spectra that show the result of using a poorly aligned flood gun on modern XPS instruments equipped with a monochromatic aluminum Kalpha x-ray source. This guide is focused on the XPS measurement of insulators—nonconductive metal oxides and polymers. This guide shows that by measuring commonly available polymers (polypropylene and polyethylene terephthalate) or ceramic materials (SiO2 and Al2O3), the operator can easily characterize the good and bad effects of XY position settings and other settings provided by modern electron flood gun systems. This guide includes many original, never-before-published XPS peak full width at half maximum (FWHM) that will greatly assist peak-fitting efforts. This guide reveals a direct correlation between electron count-rate and best charge-control settings. This guide discusses sample and instrument issues that affect surface charging and explains how to check the quality of charge control by measuring the FWHM and binding energy of C (1s) or O (1s) spectra produced from the sample currently being analyzed. A list of other charge-control methods is provided, along with advice and a best-known method. The availability of large extensive databases of actual spectra is extremely beneficial to users who need real-world examples of high quality chemical state spectra to guide their in-house efforts to collect high quality spectra and to interpret valuable information from the peak-fits of those spectra.

EDNA Adsorption onto Microplastics: Impacts of Water Chemistry and Polymer Physiochemical Properties.

Adsorption of biomacromolecules onto polymer surfaces, including microplastics (MPs), occurs in multiple environmental compartments, forming an ecocorona. Environmental DNA (eDNA), genetic material shed from organisms, can adsorb onto MPs which can potentially either (1) promote long-range transport of antibiotic resistant genes or (2) serve to gain insights into the transport pathways and origins of MPs by analyzing DNA sequences on MPs. However, little is known about the capacity of MPs to adsorb eDNA or the factors that influence sorption, such as polymer and water chemistries. Here we investigated the adsorption of extracellular linear DNA onto a variety of model MP fragments composed of three of the most environmentally prevalent polymers (polyethylene, polyethylene terephthalate, and polystyrene) in their pristine and photochemically weathered states. Batch adsorption experiments in a variety of water chemistries were complemented with nonlinear modeling to quantify the rate and extent of eDNA sorption. Ionic strength was shown to strongly impact DNA adsorption by reducing or inhibiting electrostatic repulsion. Polyethylene terephthalate exhibited the highest adsorption capacity when normalizing for MP specific surface area, likely due to the presence of ester groups. Kinetics experiments showed fast adsorption (majority adsorbed under 30 min) before eventually reaching equilibrium after 1-2 h. Overall, we demonstrated that DNA quickly binds to MPs, with pseudo-first- and -second-order models describing adsorption kinetics and the Freundlich model describing adsorption isotherms most accurately. These insights into DNA sorption onto MPs show that there is potential for MPs to act as vectors for genetic material of interest, especially considering that particle-bound DNA typically persists longer in the environment than dissolved DNA.

Study on density, shape, color, and composition of microplastics in sediments at the Han River estuary (Da Nang)

Plastic pollution is recorded in terrestrial and aquatic ecosystems. Plastic waste exposed to the environment causes many problems for the environment and all forms of life. This study was conducted to evaluate the microplastic pollution in sediments at the Han River estuary (Da Nang). The analysis results at 8 survey locations showed that microplastics appeared in all samples and there was heterogeneity in density at 8 locations, ranging from 348.2÷3567.8 MPs/kg. Microplastic sizes in the range of 50÷150 μm account for the highest proportion with a value of 2531 MPs/kg, followed by sizes &gt; 500; 20÷50; 50÷150, and 300÷500 μm with ratio values of 2034.2; 1292.1; 842.1, and 595.9 MPs/kg, respectively. The fibers and fragment microplastic forms accounted for most sediment samples up to 98.6%, the white color of microplastic recorded an average value of 49.8%, accounting for nearly half of the microplastics total found. FTIR spectrum shows that PET (Polyethylene Terephthalate) polymer has the highest density with 38.7%; followed by Polyester 25.1%; Nylon 12.9%; Polypropylene 5.4%; remaining polymers such as PVC (polyvinylchloride), PS (polystyrene), PE (Polyethylene), HDPE (High Density Polyethylene), etc. account for a fairly low proportion ranging from 0.7÷2.7%. This source of microplastic pollution is closely related to civil and service activities on both sides of the river. Therefore, in addition to changing environmental management measures, it is nessesary to research to understand the mechanisms that affect the transport, deposition, and interactions of microplastics with organisms living in this sediment environment.

Identification and quantification of microplastics in salts by complementary approaches using pyrolysis-gas chromatography/quadrupole-time of flight mass spectrometry (Py-GC/QTOFMS) and laser direct infrared (LDIR) chemical imaging analysis

Microplastics (MPs) and nanoplastics (NPs) have been suspected as contaminants in various foodstuffs, including salts, all over the world. Regarding the different sizes and polymer types, the mass concentrations of actual plastic particles in salt are not very clear. The purpose of this study is to develop a scalable method for qualitative and quantitative analysis of MPs and NPs by using Pyrolysis Gas Chromatography Quadrupole-Time of Flight mass spectrometry (Py-GC/QTOFMS) to detect their mass concentrations in salt samples. The targeted and suspected lists of polymers in salts were compiled based on the combined results of the high-resolution mass spectrometry (HRMS) full scanning with auxiliary MS dataset and the laser direct infrared (LDIR) chemical imaging analysis. The seven targeted MPs with polymer standards, i.e., polyvinyl chloride (PVC), polymethyl methacrylate (PMMA), polypropylene (PP), polystyrene (PS), polyethylene (PE), polyethylene terephthalate (PET), and polycarbonate (PC), were first subjected to a full MS scanning mode of the Py-GC/QTOFMS analysis. Subsequently, the parental masses of their pyrolysis compounds were used as the seeds to generate the related daughter masses. This process established both retention time and mass-pairs matching for the target MS/MS mode for enabling the identification and quantification of the particles. The suspected MPs with a matching degree >0.65 in the LDIR list were explored either by the full scan MS. Only PVC was identified, and PET was suspected. The Py-GC/QTOFMS result is complementary and comparable to the LDIR detection with the matching degree >0.85. We identified that PVC and PET (suspected) can be measured in both commercial and bulk sea salts, and their concentrations in sea salts are much higher than in rock salts, implying heavy contamination of the seawater.

Occurrence, distribution and sources of microplastics in typical marine recirculating aquaculture system (RAS) in China: The critical role of RAS operating time and microfilter

Industrial mariculture, a vital means of providing high quality protein to humans, is a potential source of microplastics (MPs) which have recently received increasing attention. This study investigated the occurrence and distribution of microplastics in feed, source water and recirculating aquaculture system (RAS) with long & short operating times as well as in fish from typical industrial mariculture farms in China. Results showed that microplastics occurred in all samples with the average concentration of 3.53 ± 1.39 particles/g, 0.70 ± 0.17 particles/L, 1.53 ± 0.21 particles/L and 2.21 ± 0.62 particles/individual for feed, source water, RAS and fish, respectively. Microplastics were mainly fiber in shape, blue in color and 20–500 μm in size. Compared with short operated RAS, long operating time led to higher microplastic concentration in RAS, especially that of microplastic in 20–500 μm, granular and blue. Regardless of short or long operating time, microplastics in RAS mainly gathered in culture tank, tank before microfilter and fixed-bed biological filter, and the microfilter removed efficiently the microplastic with the shape of film, granule, fragment as well as those with size > 1000 μm. As for the polymer types, polyamide (PA, 71.9 %) and polyethylene terephthalate (PET, 65.7 %) dominated in feed and source water, respectively, which may be the reason for the high proportion of PA (38.8 % and 26.4 %) and PET (31.8 % and 30.2 %) in RAS and fish. In addition, polypropylene (PP) was also detected in RAS (18.7 %) and fish (22.6 %), indicating that other plastic facilities such as PP brush carrier also made a contribution. Positive matrix factorization (PMF) model revealed three sources of MP in RAS, namely plastic facilities, industrial sewage and plastic packaging products. Our results provided a theoretical basis for the management of MP in RAS.

Inkjet-Printed Multiwalled Carbon Nanotube Dispersion as Wireless Passive Strain Sensor.

In this study, a multiwalled carbon nanotube (MWCNT) dispersion is used as an ink for a single-nozzle inkjet printing system to produce a planar coil that can be used to determine strain wirelessly. The MWCNT dispersion is non-covalently functionalized by dispersing the CNTs in an anionic surfactant, namely sodium dodecyl sulfate (SDS). The fabrication parameters, such as sonication energy and centrifugation time, are optimized to obtain an aqueous suspension suitable for an inkjet printer. Planar coils with different design parameters are printed on a flexible polyethylene terephthalate (PET) polymer substrate. The design parameters include a different number of windings, inner diameter, outer diameter, and deposited layers. The electrical impedance spectroscopy (EIS) analysis is employed to characterize the printed planar coils, and an equivalent electrical circuit model is derived based on the results. Additionally, the radio frequency identification technique is utilized to wirelessly investigate the read-out mechanism of the printed planar MWCNT coils. The complex impedance of the inductively coupled sensor undergoes a shift under strain, allowing for the monitoring of changes in resonance frequency and bandwidth (i.e., amplitude). The proposed wireless strain sensor exhibits a remarkable gauge factor of 22.5, which is nearly 15 times higher than that of the wireless strain sensors based on conventional metallic strain gauges. The high gauge factor of the proposed sensor suggests its high potential in a wide range of applications, such as structural health monitoring, wearable devices, and soft robotics.

Influence of Plastic Waste Management on the Environment: A review

Plastics have become a modern-day nuisance to the environment and man due to improper management at their end-of-life. The structure and additives in fossil-based plastics make them non-biodegradable and, therefore, can persist in the environment for hundreds of years. Since a small percentage of plastic waste is recycled annually (9%) most of this plastic waste is being managed by open-air incineration or disposal in landfills where these additives can easily contaminate the air, soil, and water apart from the fact that a lot of these plastic waste find their way into our water bodies resulting to a lot of harm to the Eco-system. Recycling of plastic is an effective means of tackling the menace of plastic pollution, with chemical recycling as the most effective recycling process as it completely removes the waste plastic from the environment. Manufacturing and use of bioplastics like Polylactic acid, a good substitute for fossil-based polymer polyethylene terephthalate (PET), is a welcome development with the People’s Republic of China championing in the production. Legislative tools have been enacted in countries across the globe banning the use and manufacturing of single-use plastic bags. The implementation of this legislative move has been effective in some countries like the People’s Republic of China, Morocco, and Rwanda. Nigeria enacted the Plastic prohibition bill banning the manufacturing, use, and importation of all plastic bags in May 2019. This ban does not affect the behavioral and plastic management system in Nigeria as plastic bags are still used in cities across the country, littered in waterways and landfills. Therefore, there is a need to review the bill to include waste generation and management. Emphasis should also be placed on the production, and use of cost-effective bioplastic polymers and products

Bipolar Current Collectors of Cu/polymer/Al Composite for Anode‐Free Batteries

AbstractThe all‐in‐one design of cathode and anode is a promising strategy to improve energy density and assembly efficiency for lithium batteries. However, it is an important prerequisite to combine negative and positive current collectors in a single sheet. Here, an asymmetric structure of bipolar composite current collector (BCCC), thin copper (Cu) and aluminum (Al) metal layers respectively deposited on each side of a thin polyethylene terephthalate (PET) polymer substrate is developed. Unlike conventional metal foils, the electronically insulative polymer blocks electron transfer between the cathode and anode coated on each side of BCCC. Buckling‐based mechanics measurement and molecular simulation are conducted to quantitatively evaluate the interfacial strength of metal/polymer, which is enhanced by introducing an intermediate chromium (Cr) layer. For applications in anode‐free wound batteries, the integrated sheet of separator/cathode/BCCC can simplify the alignment of the electrodes during the winding process. Without special surface and electrolyte optimizations, a higher Coulombic efficiency (99.1%) and larger capacity retention (50.0%) are achieved after 100 cycles in the LiNi0.8Co0.1Mn0.1O2 anode‐free battery than the battery using Cu foils.

Evaluation of the Mechanical Performance of Concrete Reinforced with PET Fibers: A Sustainable Approach

Most of the bottles manufactured with PET polymer (polyethylene terephthalate) are used in beverage packaging and, after use, are turned into garbage, causing environmental problems. The concept of recycling and reuse of these materials for use in civil construction can become an interesting solution for the reduction of urban solid waste that would be destined to the formation of large volumes in sanitary landfills. Seeking to minimize this problem, this work used discarded PET bottles, ground into fibers, to prepare a concrete-based composite. The behavior of concrete composites with the addition of PET fibers in different compositions 7.5 kg/m³, 10 kg/m³ and 12.5 kg/m³ was evaluated. The choice of these concentrations aimed to study the addition of a reasonable amount of PET, characterizing greater reuse of a recycled material, seeking to provide a reinforcement effect in the cementitious matrix. The samples were subjected to mechanical tests of axial compression and diametral compression in a duly calibrated hydraulic press. For the axial compression test, the composite with 10 kg/m³ showed better mechanical performance. Probably at this content, the fibers were better distributed in the concrete for axial compression, resisting more to the fracture point, surpassing the composite of 12.5 kg/m³ by 24% in resistance to compression. For the axial compression test, the composite with 10 kg/m³ showed better mechanical performance, because in this composition there was an ideal amount for the homogenization of the PET fibers in the concrete, achieving a greater reinforcement effect. For the permeability test, the composites prepared with higher percentages of PET showed a lower percentage of permeability (44% lower than the content of 7.5 kg/m³), absorbing less water in this composition, in an axial position. This can be attributed to the fact that the distributed PET fibers act as an impermeable barrier, offering greater resistance to water absorption in the material.