Polyethylene Terephthalate Polymer Research Articles

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.

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.

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.

Determinants of microbial colonization on microplastics through wastewater treatment processes: The role of polymer type and sequential treatment

This study examines the microbial colonization characteristics of microplastics (MPs) in wastewater treatment plants (WWTPs), focusing on polymer types (High-Density Polyethylene (HDPE) and Polyethylene Terephthalate (PET)) and various stages of wastewater treatments. Through individual and sequential deployment approaches, the research aimed to identify the determinants of bacterial colonization on MPs, whether they were introduced at each stage of treatment individually or in sequence from primary to tertiary stages. The study revealed that the stage of wastewater treatment profoundly influenced bacterial colonization on the polymer types MPs, with bacterial attachment being largely niche-specific. HDPE showed increased sensitivity to wastewater composition, leading to selective biofilm formation. For instance, in HDPE, Firmicutes accounted for 25.1 ± 0.04 % during primary treatment, while Alphaproteobacteria increased significantly in the tertiary treatment to 19.8 ± 0.1 %. Conversely, PET exhibited a stochastic pattern of bacterial colonization due to differences in surface hydrophilicity. Additionally, in sequential deployments, a notable shift towards stochastic bacterial attachment on MPs, particularly with HDPE was observed. The Shannon diversity values for MP biofilms were consistently higher than those for wastewater across all stages, with PET showing an increase in diversity in sequential deployments (Shannon diversity: 5.01 ± 0.03 for tertiary stage). These findings highlight the critical role of MPs as carriers of diverse bacteria, emphasizing the necessity for strategies to mitigate their impact in WWTPs. This study presents a significant advancement in our understanding of the interactions between MPs and microbial populations in WWTP environments.

Microbes Isolated from Landfill Soil Utilize Polyethylene Terephthalate (PET) as Their Sole Source of Carbon: An Unexplored Possibility of Bioremediation in Bangladesh

Plastic products are so extensively used that they continue to strain the already overburdened waste management system and, inevitably, the global climate. Biodegradation is a sustainable remedy. Here, we report a few microorganisms isolated from landfill soil near Dhaka that thrive especially on polyethylene terephthalate (PET) polymers. Soil samples were subjected to three enrichment cycles that contained no carbon except PET. Pure isolates were recovered and incubated on minimal agar containing PET as the sole carbon. A morphological examination was carried out. Potential PET-degrading enzyme sequences from the isolates and other microalgae were analyzed for homology using BLASTP and TBLASTN, and multiple sequence alignment (MSA) was performed to assess conserved domains. Six isolates were obtained. Two isolates grew around the PET film but did not grow sufficiently in other areas of the minimal agar. Two other isolates with greenish pigmentation flourished around the PET film as well as on other areas of the agar. One of the green cells resembled Aphanocapsa, with irregular shapes and occasionally brown dense bodies, while the others looked round like Microcystis. Homology analysis revealed the hypothetical PETases in green cells contained the highly conserved catalytic triad (Ser-His-Asp) at the active site, as always found in alpha-beta hydrolase fold containing enzymes. Microbes isolated from two landfill sites in the vicinity of Dhaka have been adapted to utilize PET as a carbon source. In the future, sequencing and further characterization would be necessary to validate the findings. Microalgal systems demand increased focus, given their potential to offer valuable resources for bioremediation.

Synthesis of polymethyl methacrylate/depolymerized polyethylene terephthalate blend reinforced by titanium dioxide nanoparticles for dental fillings applications

The aim of this study is to use recycled waste materials to modify the performance of composites used as dental fillings. For this purpose, depolymerized polyethylene terephthalate (DPET) polymers were prepared by recycling waste polyethylene terephthalate (PET) using the glycolysis process. DPET was then blended with polymethyl methacrylate (PMMA) at different weight percentages. Polymer blends were subjected to mechanical, physical, and biological tests. It is evident that PMMA blended with a 5 wt% of DPET exhibits the highest compressive strength which is approximately two times that obtained from neat PMMA, highlighting the suitability of these resins to replace amalgam and to be considered for dental restorations. It was also found that the water absorption of the blends investigated is relatively stable at 5 wt% DPET. The SEM images showed no distinguishable phases, highlighting the high compatibility between DPET and PMMA. The biological tests, including in vitro cytotoxicity, showed that the cell viability mean values of PMMA containing 5 wt% DPET is higher than that of control group. Interestingly, in dental practice, the reliable in vitro cytotoxic approach is considered as an important aid in clinical procedures in the use of dental filling systems. The microbiology study has shown that the inhibition zones against Streptococcus mutans of PMMA: 5 wt% DPET is higher than the control group. According to the obtained results, the blend of PMMA: 5 wt% DPET was selected as an optimum blend, which was then reinforced with various weight percentages of nano-sized titanium dioxide (TiO2). The composites were then tested under compression, microhardness, and impact tests. The results demonstrated the significant impact of TiO2 on enhancing the properties of the composites investigated. This can provide a new protocol for synthesizing nanocomposite materials for dentistry.

Seasonal variation of microplastics in tropical mangrove waters of South-western India

The current study investigates the seasonal variations in microplastic (MP) contamination, specifically those ranging in size from 0.1 mm to 5 mm, within the tropical mangroves of Kota, South-western India. Mean concentrations ( ± standard deviation) of 1.42 ± 0.92 MPs/L (post-monsoon), 0.62 ± 0.38 MPs/L (pre-monsoon), and 0.19 ± 0.08 MPs/L (monsoon) were observed. Fibers emerged as the most abundant category across all samples, with a dominant size fraction of less than 1 mm. Fourier Transform Infrared Spectroscopy-Attenuated Total Reflectance (FTIR-ATR) analyses identified various polymer types, including polypropylene (PP), polyethylene terephthalate (PET), high-density polyethylene (HDPE), low-density polyethylene (LDPE), polystyrene (PS), and polyvinyl chloride (PVC). Potential sources of microplastic contamination in the region could be ascribed to tourism, marine product-related industries, prawn farming, and residents. The findings of this study offer crucial insights into the seasonal fluctuations of microplastic contamination in the Kota mangrove ecosystem.

Effects of microplastics on microbial community dynamics in sediments from the Volturno River ecosystem, Italy

In this study, the sources, abundance, and ecological implications of microplastic (MP) pollution in Volturno, one of the main rivers in southern Italy, were explored by investigating the MP concentration levels in sediments collected along the watercourse. The samples were sieved through 5- and 2-mm sieves and treated with selective organic solvents. The polymer classes polystyrene (PS), polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polycarbonate (PC), nylon 6 (PA6), and nylon 6,6 (PA66) were quantified using pyrolysis–gas chromatography–mass spectrometry (Py-GC/MS) and high-performance liquid chromatography (HPLC). Furthermore, a 16S rRNA metagenomic analysis was performed using next-generation sequencing in Ion Torrent™ to explore the bacterial taxonomy and ecological dynamics of sediment samples. The MPs were detected in all samples collected from the study area. PP and PET were the most abundant and frequently detected polymer types in the analysed samples. The total MP concentration ranged from 1.05 to 14.55 ppm (parts per million), identifying two distinct data populations: high- and low-MP-contaminated sediments. According to the Polymer Hazard Index (PHI), MP pollution was categorised as hazard levels III and IV (corresponding to the danger category). Metagenomic data revealed that the presence of MPs significantly affected the abundance of bacterial taxa; Flavobacteraceae and Nocardiaceae, which are known to degrade polymeric substances, were present in high-MP-contaminated sediments. This study provides new insights into the ecological relevance of MP pollution and suggests that microorganisms may serve as biomarkers of MP pollution.

Chemical characterization of virgin and recycled polyethylene terephthalate films used for food contact applications

Plastic is commonly used for food packaging, of which plastic polymer polyethylene terephthalate (PET) is widely used in the food and beverage industry. Furthermore, PET is the most suitable and recyclable plastic polymer used in food contact applications due to its functional properties: inertness and low diffusion of gases and migrants. However, using recycled PET (rPET) for food contact applications requires that the rPET is chemically safe. In this study, we use mass spectrometry and spectroscopy-based methods to characterize the chemical composition of virgin PET (vPET) and rPET. The mass spectrometric analysis demonstrated more peaks in rPET and the spectroscopic analysis revealed degradation of the rPET after the recycling process. The tentatively identified peaks in both vPET and rPET were mainly PET oligomers. The present work suggests the importance of testing PET obtained from one or more recycling processes to evaluate the effect on the polymer properties, chemical migration, and chemical safety of rPET for food contact.

Ultrafiltration membrane fabricated from polyethylene terephthalate plastic waste for treating microalgal wastewater and reusing for microalgal cultivation

Current study had made a significant progress in microalgal wastewater treatment through the implementation of an economically viable polyethylene terephthalate (PET) membrane derived from plastic bottle waste. The membrane exhibited an exceptional pure water flux of 156.5 ± 0.25 L/m2h and a wastewater flux of 15.37 ± 0.02 L/m2h. Moreover, the membrane demonstrated remarkable efficiency in selectively removing a wide range of residual parameters, achieving rejection rates up to 99%. The reutilization of treated wastewater to grow microalgae had resulted in a marginal decrease in microalgal density, from 10.01 ± 0.48 to 9.26 ± 0.66 g/g. However, this decline was overshadowed by a notable enhancement in lipid production with level rising from 181.35 ± 0.42 to 225.01 ± 0.11 mg/g. These findings signified the membrane's capacity to preserve nutrients availability within the wastewater; thus, positively influencing the lipid synthesis and accumulation within microalgal cells. Moreover, the membrane's comprehensive analysis of cross-sectional and surface topographies revealed the presence of macropores with a highly interconnected framework, significantly amplifying the available surface area for fluid flow. This exceptional structural attribute had substantially contributed to the membrane's efficacy by facilitating superior filtration and separation process. Additionally, the identified functional groups within the membrane aligned consistently with those commonly found in PET polymer, confirming the membrane's compatibility and efficacy in microalgal wastewater treatment.

Degree of Wettability and Aging of PVC and PET Polymers Treated by Plasma Immersion or Deposition

The wettability, aging characteristics, and optical transmittance in the visible region following Plasma Immersion (PI) or Plasma Immersion Ion Implantation (PIII) treatment of polymers were studied. In addition, structural and chemical modifications of the polymers were examined. The polymers investigated were white Polyvinyl chloride (PVC) and Polyethylene terephthalate (PET). Initially, plasmas of nitrogen (N2) were employed, aiming to produce hydrophilic surfaces. In contrast, sulfur hexafluoride (SF6) plasma treatments produce high surface fluorination, which tends to increase hydrophobicity. Isopropyl alcohol (IPA) was mixed with SF6 or N2 to deposit a series of organic films. Aging effects over 30 days on the contact angle, q, were measured for the polymer surfaces. Conventional plasma immersion (PI) tended to decrease of θ for N2 plasma treatments, with or without IPA, and to increase θ values ​​for samples immersed in IPA/SF6 plasma.  The highest value of θ was 140º for IPA/SF6 plasma treatments, while the smallest θ was 20º for N2 or IPA/N2 treatments. There was an ideal condition under which θ was stable upon aging. The results obtained suggest the developed treatment enables the preparation of polymers with distinct wettability properties depending of the nature of the plasma with overall reasonable aging stability. Moreover, the opaque character of these materials makes them interesting for the production of bags, boxes, bottles, food packaging, among others.

Effects Caused by the Ingestion of Microplastics: First Evidence in the Lambari Rosa (Astyanax altiparanae).

Microplastics are a class of contaminants that pose a threat to aquatic biota, as they are easily found in aquatic ecosystems and can be ingested by a wide variety of organisms, such as fish. The lambari rosa (Astyanax altiparanae) is a microphage fish, which feeds on microscopic beings and particles, making it potentially susceptible to ingesting MPs discarded in the environment. In addition, this fish is of great economic and food importance, as it is used for human consumption. This study aimed to evaluate the accumulation and possible toxicological effects caused to lambari rosa (n = 450) by the ingestion of polyethylene (PE) and polyethylene terephthalate (PET) MPs, since the MPs of these polymers in the form of granules, fragments, and fibers are the most commonly reported in the aquatic environment. The parameters investigated here were the quantitative analysis of ingested MPs using microscopic and staining techniques, as well as the mortality rate, malformations/injuries, and impaired weight gain. At the end of the experiment, it was concluded that MPs from both polymers accumulated in the gastrointestinal tract of the lambari rosa, and that dietary exposure, especially to the PET polymer, was responsible for increasing the mortality rate in this species.

EXPERTISE OF PYRAMID TEA BAGS BY OPTICAL MICROSCOPY AND FTIR-SPECTROSCOPY METHODS. MICROPLASTICS FORMATION IN BREWED TEA

Eight brands of pyramid tea bags on the Ukrainian market were studied: Sun Gardens (1), Lovare (2), Curtis for Mc Donalds (3), Curtis (4), Lipton (5), Premiya (6), Sonnet (7) and Loyd (8). Using FTIR spectroscopy, it was found that the pyramids of the bags are made of thermoplastic polymers polyethylene terephthalate (samples 1-7) and polylactic acid (sample 8). The threads attached to the pyramids are made of thermoplastic polymers polypropylene (samples 1,2,4-7), polyethylene terephthalate (sample 4) and polylactic acid (sample 8). The specific optical rotation of polylactic acid [α]D25 is about -150° (c=1, CHCl3), which refers to poly(L-lactic acid). Using optical microscopy, it was established that the structure of the pyramids are divided into those made of plain woven fabrics (samples 1-3) and heat-bonded nonwoven fabrics (samples 4-8). The tea bags (samples 1-3) exhibit a well patterned net structure (mesh) with the pores perceived to be uniform and regular. The tea bags made of nonwoven materials have an irregular network consisting of compact and random arrangement of fibers. The fibers are pleated randomly, generating irregular pores. Nonwoven fabrics are made from fibers with a diameter of 12-18 µm, woven fabrics are made from fibers with a diameter of 48-54 µm. The area density of nonwoven fabrics is 18.5-20.3 g/m2, the area density of woven fabrics is 22.0-22.7 g/m2. The threads are made by twisting several single-twisted yarns. The structure of threads are a cabled yarn from three 2-ply yarns (samples 1,8), 4-ply yarn (samples 2-4,6,7) and 4-ply multyfilament yarn (samples 5). The final twist of the plied yarn/cord is S-twist. The primary structural element of threads in the case of samples 1-4, 6-8 are staple fibers, of sample 5 are multyfilament fibers. Each empty pyramids and thread was steeped at 95oC for 5 min in 10 mL of water. It has been established that the shape of microplastic particles formed in beverages during tea brewing is determined by the primary structure of tea bags. Both pyramids and threads release irregularly shaped microplastic particles.