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The growing concerns regarding foodborne illnesses related to fresh produce accentuate the necessity for innovative material solutions, particularly on surfaces that come into close contact with foods. This study introduces a sustainable, efficient, and removable antimicrobial and antifouling coating ideally suited for hydrophobic food-contact surfaces such as low-density polyethylene (LDPE). Developed through a crosslinking reaction involving tannic acid, gelatin, and soy protein hydrolysate, these coatings exhibit proper stability in aqueous washing solutions and effectively combat bacterial contamination and prevent biofilm formation. The unique surface architecture promotes the formation of halamine structures, enhancing antimicrobial efficacy with a rapid contact killing effect and reducing microbial contamination by up to 5 log10 cfu·cm-2 against both Escherichia coli (Gram-negative) and Listeria innocua (Gram-positive). Notably, the coatings are designed for at least five recharging cycles under mild conditions (pH6, 20 ppm free active chlorine) and can be easily removed with hot water or steam to refresh the depositions. This removal process not only conveniently aligns with existing sanitation protocols in the fresh produce industry but also facilitates the complete eradication of potential developed biofilms, outperforming uncoated LDPE coupons. Overall, these coatings represent sustainable, cost-effective, and practical advancements in food safety and are promising candidates for widespread adoption in food processing environments.

In accordance with the Circular Economy Package of the European directive, the Spanish government compels manufacturers of plastic bags to include into their products a minimum of 70% of polyethylene (PE) waste. Following this mandate can be challenging and requires a deep knowledge of the alterations produced by the recycling in the main components of a plastic bag film: lineal low-density polyethylene (LLDPE), the LLDPE recycled post-industry, generated as waste from an industrial process (rLLDPE) and the PE recycled from post-consumer use (rPE), that has been picked up, cleaned, and reprocessed. This study provides insight in the macro and microstructural changes produced by several cycles of recycling in these materials. Specimens in the form of film for supermarket bags formed with these polymers have been subjected to several recycling sequences. The process closely mimics industrial processes. Four cycles have been applied to the samples. The evolution of mechanical properties, including tensile strength, elongation at break, and tear and impact tests, shows an obvious decrease due to degradation that is not an impediment for practical use after the four cycles of recycling according to the main specifications defined by the producer. Colorimetric measurements reveal no significant variations in the color of the films. The results of the FTIR and TGA analysis show degradation phenomena and changes in crystallinity in branching and the apparition of crosslinking that are in consonance with the mechanical data. There is also a difference between both types of recycled PE. In general, rLLDPE is more affected by the recycling than rPE. According to our findings, the limiting property would be the tearing. By comparing these values with bags available in the market, manufactured from 70–80% recycled material, we can infer that while two reprocessing cycles can lead to good results, a maximum of four cycles of recycling is advisable, The manuscript is part of grant PID2021-126165OB-I00 founded by MCIN/AEI/10.13039/501100011033 and by ERDF A way of making Europe by the European Union. ​We are significantly grateful for the work carried out by S. Fernández Ayala and E. Molina Salazar in the laboratories of the company Sphere Spain, Postprint (published version)

Today, comprehensive measures are being implemented around the world and certain results are being achieved in the field of further deepening economic reforms in the building materials industry and the rapid development of the network, increasing the production of new modern building materials, structures and products, and expanding their range. Expanding the range of manufactured building materials, increasing the share of production of modern, convenient, and high-quality products based on a localization program, reducing imports, as well as the further development of the industry remain pressing issues of today. The studies present methods for increasing the fire resistance of polymer building materials obtained based on fly ash from the furnaces of the Shirin Thermal Power Plant and JSC Uzmetkombinat, waste phosphogypsum generated at JSC Maxam-Ammafos, physical, mechanical, and thermodynamic properties, and also studied optimal proportions for obtaining composites of fire-resistant polymer building materials. To conduct an experimental study, particles of technogenic industrial waste of the most optimal size, types of filler, and necessary components were selected. Studies of the elemental composition of industrial technogenic waste and X-ray diffraction analysis have shown that they consist mainly of silicon dioxide, which consists of more than 80% of the amorphous phase. Based on the analysis of the X-ray phase structure, it was determined that the introduction of additives into the fly ash fillers of the Shirin Thermal Power Plant and Uzmetkombinat JSC, as well as phosphogypsum waste from Maxam-Ammofos JSC, leads to an increase in the thermal stability of polymer materials. The main reason for this is explained by the fact that the composition of fly ash and phosphogypsum waste introduced into the polymer composite contains metal oxides, silicon oxide, and phosphorus compounds, which are resistant to temperatures and have fire-retardant properties. The fire r

Plastic waste, especially positively buoyant polymers known as polyolefins, are a major component of floating debris in the marine environment. While plastic colonisation by marine microbes is well documented from environmental samples, the succession of marine microbial community structure over longer time scales (> > 1 month) and across different types and shapes of plastic debris is less certain. We analysed 16S rRNA and 18S rRNA amplicon gene sequences from biofilms on polyolefin debris floating in a flow-through seawater tank in Hawaii to assess differences in microbial succession across the plastic types of polypropylene (PP) and both high-density polyethylene (HDPE) and low-density polyethylene (LDPE) made of different plastic shapes (rod, film and cube) under the same environmental conditions for 1 year. Regardless of type or shape, all plastic debris were dominated by the eukaryotic diatom Nitzschia, and only plastic type was significantly important for bacterial community structure over time (p = 0.005). PE plastics had higher differential abundance when compared to PP for 20 bacterial and eight eukaryotic taxa, including the known plastic degrading bacterial taxon Hyphomonas (p = 0.01). Results from our study provide empirical evidence that plastic type may be more important for bacterial than eukaryotic microbial community succession on polyolefin pollution under similar conditions.

The production and pollution of plastic present a significant threat to global ecosystems, where annual plastic emissions in aquatic ecosystems are projected to triple between 2020 and 2030. Currently, plastics are widely used for food packaging but depending on the polymers, properties, the recyclability ratio of the plastics varies. Polymers, such as polyethylene (PE), polyurethane (PUR), and expanded polystyrene (EPS), are widely used for packaging and transporting foods such as fresh fish, where multi-use fish tubs often consist of PE and/or PUR and single-use boxes of EPS. This study evaluated the environmental impacts of reusable tubs of different volumes and sizes made of PE/PUR vs single-use EPS boxes, transporting 1000 tons (T) of fresh fish from Iceland to Europe, per year based on life cycle assessment methodology. This is to identify the packaging solution with the lowest environmental impact. The overall results show that multi-use tubs had lower environmental impacts when transporting 1000 T of fresh fish from Iceland to Europe per year, even during first year of usage. For Global warming impacts, producing and using EPS boxes for transporting 1000 T of fresh fish was 141 T CO2-eq and ranged from 4 to 46 T CO2-eq for variating multi-use packaging solutions for one year. The weight of the raw materials (plastics) and size of the tubs were key factors affecting the environmental impacts when transporting the tubs.

This review focuses on the use of polyolefins in high-voltage direct-current (HVDC) cables and capacitors. A short description of the latest evolution and current use of HVDC cables and capacitors is first provided, followed by the basics of electric insulation and capacitor functions. Methods to determine dielectric properties are described, including charge transport, space charges, resistivity, dielectric loss, and breakdown strength. The semicrystalline structure of polyethylene and isotactic polypropylene is described, and the way it relates to the dielectric properties is discussed. A significant part of the review is devoted to describing the state of art of the modeling and prediction of electric or dielectric properties of polyolefins with consideration of both atomistic and continuum approaches. Furthermore, the effects of the purity of the materials and the presence of nanoparticles are presented, and the review ends with the sustainability aspects of these materials. In summary, the effective use of modeling in combination with experimental work is described as an important route toward understanding and designing the next generations of materials for electrical insulation in high-voltage transmission.

The inclusion of particles in a polymeric substrate to achieve certain properties is a well-known practice. In the case of textile substrates, this practice may deeply affect the structure of the produced yarns, as even a filament with no textile applications can be obtained. In this manuscript, titanium dioxide (TiO2) particles were incorporated into polyester (PET) chips and the influence of these fillers on the properties of yarn and fabric, and the ultraviolet protection factor (UPF) was assessed. For this purpose, rutile and anatase crystalline forms of TiO2, as well as the size of the particles, were evaluated. Moreover, parameters such as mechanical properties, orientation of the macromolecules and thermal behavior were analyzed to ensure that the textile grade is maintained throughout the production process. The results showed that the inclusion of micro- and nanoparticles of TiO2 decreases the molecular weight and tenacity of PET. Also, although orientation and crystallinity varied during the textile process, the resulting heatset fabrics did not present important differences in those parameters. Finally, the attainment of textile-grade PET-TiO2 fabrics with UPF indexes of 50+ with both rutile and anatase and micro- and nano-sized TiO2 forms was demonstrated, The authors gratefully acknowledge the financial support for this research from the Ministry of Science and Innovation of Spain (project MAT2010-20324-CO2-01) and from the National Secretary of Higher Education Science Technology and Innovation of Ecuador (SENESCYT) for fellowship No. CZ02-000926-2018, Postprint (published version)

Microplastics (MPs) and antibiotics are emerging pollutants widely found in aquatic environments, potentially causing environmental harm. MPs may act as carriers for antibiotics, affecting their environmental distribution. This study investigates the adsorption of four macrolide antibiotics and a metabolite onto two types of MPs: polyethylene terephthalate (PET) and polyethylene (PE). Results revealed a linear isotherm adsorption model, with higher adsorption to PET than to PE (R² > 0.936 for PE and R² > 0.910 for PET). Hydrophobic interactions and hydrogen bonding could be the main adsorption mechanisms, with pore filling potentially involved. Reduced particle size enhances adsorption due to the increase of active adsorption sites. This increasement is more pronounced in PE than in PET, leading to an 11.6% increase in the average adsorption of all macrolides to PE, compared to only 5.1% to PET. Dissolved organic matter inhibits adsorption (azithromycin adsorption to PE was reduced from 12% to 5.1%), while salinity enhances it just until 1% salinity. pH slightly influences adsorption, with maximal adsorption at neutral pH. Results in real samples showed that complexity of the matrix decreased adsorption. Overall, these findings indicate that PE and PET MPs can be a vector of macrolides in aquatic environments.

In the recently approved spanish RD 3/2023 on human consumption water (text transposed from the EU Directive 2020/2184) the so-called observation list is included in its article 19: there are the emerging concern pollutants taking into account their potential health risk for humans. More specifically, in Annex IV of the RD review, section 4, the national observation list is published with the reference to 17b−stradiol, nonilphenol, azithromycin and diclofenac; likewise, it is literally indicated that “microplastics will be included in the list when the European Commission adopts a standardized methodology to measure microplastics in drinking water”. For above, this article will review the position on the subject published by the EU in September 2022 from the agency that deals with this type of issues, the Common Research Center of the European Commission, known by its English acronym JRC. At the same time, we will also refer the situation in Spain. In this way, the main types of MP detected were polyester (PES), polypropylene (PP) and polyethylene (PE), while polystyrene, ABS and polyamide were also detected. At the same time, results at a DWTP were reduced >93% from raw water (0.96 MP/L) after use of sand filtration, granular actived carbon, and reverse osmosis. Finally, concentration found in drinking water was very low, between 0 and 0.05 MP/L, with an average of 0.01 MP/L., En el recientemente aprobado RD español 3/2023 sobre aguas de consumo humano, adaptación de la primitiva Directiva UE 2020/2184, se incluye en su artículo 19 la denominada Lista de Observación que engloba los denominados «contaminantes de preocupación emergente que se consideren un riesgo para la salud». Así, en el apartado 4 del Anexo IV del reseñado RD, se publica la Lista de Observación nacional con las referencias a 17b-Estradiol, nonilfenol, azitromicina y diclofenaco, indicándose literalmente además que «los microplásticos se incluirán en la lista cuando la Comisión Europea adopte una metodología normalizada para medir los microplásticos en el agua de consumo». Este artículo tiene un doble objetivo: (i) pasar revista a la última posición sobre el tema publicada por la UE en septiembre de 2022 desde el organismo que se ocupa de este tipo de cuestiones, el Centro Común de Investigación de la Comisión Europea (conocido por sus siglas inglesas como JRC); (ii) en segundo lugar, se recogerán los más recientes resultados sobre MP en aguas españolas. En este sentido, los tipos de microplásticos (MP, en adelante) mayoritariamente encontrados fueron poliéster (PES), polipropileno (PP) y polietileno (PE), detectándose, asimismo, poliestireno, ABS y poliamida. Además, los MP reducían su concentración en una ETAP desde agua bruta a (0,96 MP/L) tras filtración por arena, carbón activo granular y ósmosis inversa en más del 93 % respecto al agua cruda de entrada a planta. Finalmente, las concentraciones de MP en aguas de consumo fueron muy bajas, entre 0 y 0,05 MP/L, con un promedio de 0,01 MP/L., No recentemente aprovado RD espanhol 3/2023 sobre água para consumo humano, adaptação da primitiva Diretiva da UE 2020/2184, o Artigo 19 inclui a chamada Lista de Observação, que inclui os chamados “poluentes de preocupação emergente que são considerados um risco para a saúde”. Assim, na secção 4 do Anexo IV do referido RD, é publicada a Lista Nacional de Observação com referências ao 17b-Estradiol, ao nonilfenol, à azitromicina e ao diclofenac, indicando também literalmente que“os microplásticos serão incluídos na lista quando a Comissão Europeia adotar uma metodologia padronizada para medir microplásticos em água potável. Este artigo tem um duplo objetivo: (i)rever a última posição sobre o assunto publicada pela UE em setembro de 2022 pelo órgão que trata deste tipo de questões, o Centro Comum de Investigação da Comissão Europeia (conhecido pela sigla em inglês como JRC); (ii)em segundo lugar, serão recolhidos os resultados mais recentes sobre PM em águas espanholas. Nesse sentido, os tipos de PM mais encontrados foram poliéster (PES), polipropileno (PP) e polietileno (PE), sendo também detectados poliestireno, ABS e poliamida. Além disso, o PM reduziu sua concentração em uma ETAP de água bruta para (0,96 MP/L) após filtração através de areia, carvão ativo granular e osmose reversa em mais de 93% em comparação com a água bruta de entrada na planta. Por fim, as concentrações de MP na água potável foram muito baixas, entre 0 e 0,05 MP/L, com média de 0,01 MP/L.

The effect of iron and calcium stearates on the degradation of polyethylene (LDPE and LLDPE), under natural and artificial exposure, has been studied. The activity of stearates has been evaluated by chemiluminescence and FTIR of polyethylenes. The analysis of the molecular weight changes and content of degradation products identified by GC–MS during ageing process confirmed their pro-degrading activity. Films containing stearates exhibited lower CL emission, and revealed the higher efficiency of Fe-Stearate compared to Ca-Stearate in decomposing hydroperoxides, leading to higher degradation during processing. The results were confirmed by TGA analysis, where the weight loss onset and Tmax shifted to lower temperatures in polyethylenes with incorporation of Fe- and Ca-stearates compared to pure polymers. Polyethylenes were outdoor and accelerated exposed, and CL measured at different period of times. Chemiluminescence temperature-ramping tests under nitrogen showed the formation of a peroxide peak at lower temperature, and a significant increase in carbonyl index for PE containing stearates was found by FTIR. The results were supported by GC–MS, where the concentration of extracted products identified in the polyethylenes containing Fe-stearate was significant, and a much greater decrease in molecular weight was determined by GPC, which confirmed the development of degradation for polyethylenes with Fe-Stearates in comparison to pure or Ca-stearate polyethylenes., Ministerio de Ciencia, Innovación y Universidades, Depto. de Química en Ciencias Farmacéuticas, Fac. de Farmacia, TRUE, pub

El poli(etilè tereftalat) opac (PET-O) és el material preferit en la fabricació d'ampolles per protegir els líquids de la degradació pels raigs UV. No obstant això, el PET-O no es pot reciclar pels mateixos canals que el PET transparent ja que conté micropartícules de diòxid de titani (TiO2). En aquest estudi comparem mescles de PET opacs reciclats (rPET-O) amb una matriu de polipropilè (PP), compatibilitzat amb polipropilè-empelt-anhidre maleico (PP-g-MA) o polipropilè-empelt-glicidilmetacrilat (PP-g-GMA), a fi de determinar qué compatibilitzador confereix a les mescles millors propietats per emmotllament per injecció. Per a l'extrusió reactiva de PET opac reciclat amb un extensor de cadenes (Joncryl®), se sotmet a les formulacions a un barrejat en fos per extrusió amb PP i els compatibilitzants (70/20/10). A continuació, es fabrican mostres a partir de les mescles, compatibilitzades amb PP-g-MA o PP-g-GMA, mitjançant emmotllament per injecció. Aquestes mostres es caracteritzen per microscòpia electrònica de rastreig (SEM), calorimetria diferencial de rastreig (DSC), anàlisi tèrmica mecànica dinàmica (DMTA), proves de tracció i fractura amb mostres SENB (single-edge notch bending), que demostren que la compatibilitat serà essencial per a millora les propietats tèrmiques i mecàniques de les mescles, oferint el PP-g-GMA l'opció de compatibilització més eficaç. Se suposa que aquests resultats són un pas més a prop d'obtenir un millor procés i una alternativa per a la revalorització del PET opac postconsum, reduint la seva eliminació en abocadors i el seu impacte en el medi ambient., El poli(tereftalato de etileno) opaco (PET-O) es hoy en día el material preferido en la fabricación de botellas para proteger los líquidos de la degradación por rayos UV. Sin embargo, el PET-O no puede reciclarse por los mismos canales que el PET transparente debido a que contiene micropartículas de dióxido de titanio (TiO2). En este estudio se comparan mezclas de PET opaco (rPET-O) dentro de una matriz de polipropileno (PP), compatibilizado con polipropileno-injerto-anhídrido maleico (PP-g-MA) o polipropileno-injerto-glicidilmetacrilato (PP-g-GMA), con el fin de determinar qué compatibilizador confiere a las mezclas mejores propiedades para el moldeo por inyección. Tras la extrusión reactiva de PET opaco reciclado con un extensor de cadena (Joncryl®), se somete a las formulaciones a un mezclado en fundido por extrusión con PP y los compatibilizantes (70/20/10). A continuación, se fabrican muestras a partir de las dos mezclas, compatibilizadas con PP-g-MA o PP-g-GMA, mediante moldeo por inyección. Estas muestras, caracterizadas por microscopía electrónica de barrido (SEM), calorimetría diferencial de barrido (DSC), análisis térmico mecánico dinámico (DMTA), ensayos de tracción y de fractura con probetas de tipo SENB (single-edge notch bending), demostraron que la compatibilización era primordial para mejorar las propiedades térmicas y mecánicas de las mezclas, ofreciendo el PP-g-GMA la opción de compatibilización más eficaz. Estos resultados suponen un paso más para obtener un mejor procesado y una alternativa para la revalorización del PET opaco post-consumo, reduciendo así su eliminación en vertederos y su impacto medioambiental., Opaque poly(ethylene terephthalate) (PET-O) is nowadays the material of choice in bottles manufacturing in order to protect liquids from UV degradation. However, PET-O cannot be recycled through the same channels as transparent PET due to it containing microparticles of titanium dioxide (TiO2). This study compares blends of recycled opaque PET (rPET-O) inside a matrix of polypropylene (PP), compatibilized with either polypropylene-graft-maleic anhydride (PP-g-MA) or polypropylene-graft-glycidyl methacrylate (PP-g-GMA), in order to determine which compatibilizer gives the blends better properties for injection moulding. After reactive extrusion of opaque PET with a chain extender (Joncryl®), it undergoes melt-blending by extrusion with PP and the compatibilizers (70/20/10). Samples are then produced from the two blends, either compatibilized with PP-g-MA or PP-g-GMA, by injection moulding. These samples, characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), tensile and fracture tests with single-edge notch bending (SENB) samples, proved that compatibilizing was essential to enhance thermal and mechanical properties of the blends, with PP-g-GMA offering the most effective compatibilization option. These results are a step further to obtain better processing and revalorisation of post-consumer opaque PET, thus reducing its disposal to landfill and environmental impact.

Injection-molded polyethylene plates exhibit highly anisotropic mechanical behavior due to, e.g., the uneven orientation of the polymer chains during the molding process and the differential cooling, especially in the thickness direction. Elastoplastic finite element modeling of these plates in particular is used with isotropic yield criteria like von Mises, trading off accuracy in favor of simpler constitutive characterization and faster solution. This article studies three different anisotropic yield criteria, namely, Hill 1948, Barlat Yld91, and Barlat Yld2004-18P, for the finite element modeling of low-density polyethylene (LDPE) at large uniaxial tensile deformation and compares the accuracy and computation time with von Mises. A simplified calibration technique is investigated to identify the constitutive parameters of the studied Barlat group yield criteria. The calibration process is simplified in the sense that only uniaxial tensile tests with digital image correlation measurements are used for the calibration of all the yield criteria studied in this article, although a standard calibration procedure for the Barlat group yield criteria requires additional material testing using more demanding test setups. It is concluded that both Barlat Yld91 and Barlat Yld2004-18P yield criteria can be calibrated with only a few tensile tests and still capture anisotropy in deformation–stress–strain at different levels of accuracy. © 2023 by the authors.

Achieving efficient chemical depolymerization of waste polyolefins to monomers remains an unsolved challenge, while it could be an effective means to avoid further waste accumulation in the environment and generate economic benefits. In a recent publication by Conk et al., polyethylene (PE) is converted to propylene, the second most used monomer in the polymer industry. The conversion is achieved via a tandem catalysis approach in which partially unsaturated PE chains react with ethylene to generate propylene with yields as high as 87 %. The study is a first proof of concept showcasing a selective chemical depolymerization of PE to a monomer. Future research is expected to focus on the catalyst optimization, process design, and compatibility with contaminated and multi-polymer waste streams.

The accelerated aging of polyethylene terephthalate (PET) multifilament yarns containing nano or microparticles of titanium dioxide (TiO2), silicon carbide (SiC), or fluorite (CaF2) at a maximum percentage of 2% has been studied. For this, the yarn samples were introduced into a climatic chamber at 50 °C, 50% relative humidity, and an ultraviolet A (UVA) irradiance of 1.4 W/m2. They were then removed from the chamber after periods of between 21 and 170 days of exposure. Subsequently, the variation in weight average molecular weight, number molecular weight, and polydispersity was evaluated by gel permeation chromatography (GPC), the surface appearance was evaluated using scanning electron microscopy (SEM), the thermal properties were evaluated using differential scanning calorimetry (DSC), and the mechanical properties were evaluated using dynamometry. The results showed that, at the test conditions, there was degradation in all of the exposed substrates, possibly due to the excision of the chains that make up the polymeric matrix, which resulted in the variation in the mechanical and thermal properties depending on the type and size of the particle used. This study provides insight into the evolution of the properties of PET-based nano- and microcomposites and might be helpful when selecting materials for specific applications, which is of great interest from an industrial point of view, The authors gratefully acknowledge the financial support for this research from the Ministry of Science and Innovation of Spain (Project MAT2010-20324-CO2-01) and the National Secretary of the Higher Education Science Technology and Innovation of Ecuador (SENESCYT) for Fellowship No. CZ02-000926-2018, Postprint (published version)

This is a study to optimize the PET plastic polymer bottle blower manufacturing process. The market is being more competitive, and it is really important to be able to offer a good quality service, while reducing the CO2 footprint during the manufacturing process. Therefore, has been researched in order to improve the energy efficiency. Reducing the consumption during the manufacturing process or contributing with recycled plastic materials. As a result, manufacturing costs were reduced maintaining the same quality standards. Three potential blower proposals were analyzed; oven low consumption laps replacement, low pressure molds new technology implementation and PET preforms replacement with recycled PET preforms. Trial tests were carried out during the blower manufacturing process to test the efficiency of each proposal. The packaging result was analyzed and the quality standard was tested with an optimal result. The final testing result was successful. The lower consumption lamps allow a 20% electricity consumption reduction maintaining same quality standard. The industrial blowers are compatible with recycled PET preforms and may contribute with the environment. However, spite of prior results, low pressure molds were not able to pass the standards quality tests due to several errors with the packaging volume., Aquest projecte es basa en fer un estudi d’optimització del procés de fabricació d’ampolles de plàstic en bufadores de polímer PET. Cada vegada més, el mercat és més competitiu i és important poder oferir un servei de qualitat, alhora que contribuir al medi ambient i reduir a petjada de CO2 durant els processos de fabricació dels envasos. Detectant aquesta problemàtica al mercat, s’estudia propostes de millora per augmentar l’eficiència energètica, de varies maneres: reduint el consum que generen les maquines i també contribuint en una millora amb el medi ambient utilitzant materials de plàstics reciclats. Com a conseqüència, es redueixen els costos de fabricació, sempre mantenint els estàndards de qualitat. S’estudien tres possibles propostes de millora a implementar a les bufadores; utilitzar làmpades de baix consum pel forn de les maquines, utilitzar motlles de baixa pressió gràcies a una nova tecnologia implementada i substituir les preformes de PET per preformes de PET reciclat. El mètode utilitzat per comprovar l’eficiència de les propostes estudiades, es realitzar proves experimentals en les bufadores industrials durant el procés de fabricació d’envasos reals i analitzar els envasos obtinguts durant les produccions per comprovar els estàndards de qualitat i si les solucions son òptimes. Els resultats obtinguts després d’explorar les tres propostes son positius en el cas de les làmpades de baix consum, ja que permet obtenir un 20% de reducció del consum elèctric de la màquina i sense afectar a la qualitat durant la producció dels envasos. Per altre banda, es confirma que les bufadores industrials poden treballar sense afectacions negatives amb les preformes de PET reciclat. La utilització de PET reciclat permet reduir l’impacte ambiental de la disposició de residus plàstics, permet reduir l’esgotament de recursos, fomenta la circularitat del procés productiu. Per últim, s’obtenen resultats negatius amb els motlles de baixa pressió, ja que no s’aconsegueix ajus

En aquest treball s'ha realitzat un estudi del procés de laminació de tarjetes plastiques per abordar el problema de la fragilitat en el material de tereftalat de polietilé (PET) reciclat i multicapa. La industria de les tarjetes de pagament ha utilitzat fins el 2020 policorur de vinil (PVC) com a material majoritari en la seva producció. Per disminuir la seva petjada de carboni, comença a utilitzar materials més sostenibles com el PET reciclat. A diferencia del PVC, al ser el PET un material semicristalí, pot portar problemes de fragilitat, i tenir una amplitud de procesament més reduida que el seu antecessor. Es pot comprobar que el problema de la fragilitat es causat per un augment en la cristalinitat, realitzant una caraxterització térmica dels materials laminats a la planta de Giesecke+Devrient. A partir d'aquí, s'estudien les temperatures en les que s'aconsegueix major adhesió, així com la cristanilitat de les monocapes del material. Es va obtenir una finestra de procesament optima entre els 90°C i els 100°C, evitant el problema de l'augment de cristanilitat. A 100°C la força d'adhesió es major, mentre que si s'utilitza un parametre de 90°C es pot estalviar un 40% en temps de laminació., En este trabajo se realiza un estudio del proceso de laminación de tarjetas plásticas para abordar el problema de fragilidad en el material de tereftalato de polietileno (PET) reciclado multicapa. La industria de tarjetas de pago ha utilizado hasta 2020 policloruro de vinilo (PVC) como material mayoritario en su producción. Para disminuir su huella de carbono, empieza a utilizar materiales más sostenibles como el PET reciclado. A diferencia del PVC, al ser el PET un material semicristalino, puede traer problemas de fragilidad y tener una ventana de procesamiento más reducida que su antecesor. Se comprueba que el problema de fragilidad es causado por un aumento de cristalinidad, realizando una caracterización térmica de los materiales laminados en la planta de Giesecke+Devrient. A partir de aquí, se estudian las temperaturas a las que se consigue mayor adhesión, así como la cristalinidad de las monocapas del material. Se obtiene una ventana de procesamiento óptima entre los 90ºC y 100ºC, evitando problemas de aumento de cristalinidad. A 100ºC la fuerza de adhesión es mayor, mientras que si se utiliza un parámetro de 90ºC se puede ahorrar un 40% en tiempo de laminación., The aim of this work is to study the lamination process of plastic cards to overcome the brittleness problem of multilayer, recycled, polyethylene therephtalate (PET). The payment card industry has used polyvinyl chloride (PVC) up until 2020 as the main material for its production. In order to reduce its carbon footprint, this industry started using more sustainable materials such as recycled PET. Contrary to PVC, since PET is a semicrystalline material, it can cause fragility problems and has a narrower processing window. The root cause to the britleness issue is verified to be an increase in crystallinity by carrying out a thermal characterization of the laminated materials from Giesecke+Devrient. Then the cristallinity of the monolayers of the material is studied, along with the processing window where the adhesion force is the strongest. The results show a temperature window between 90ºC and 100ºC, where crystallinity increase is avoided. At 100ºC the adhesion force acchieved is stronger. However, using a temperature of 90ºC can save up to 40% in the laminating process time.

This review provides an overview of use of natural fibers and potential use of rice straw fibers as reinforcement in composite. As it is known that after china, India is the second largest country in the world producing rice as food grains. As a result of producing more amount of rice a large amount of rice straw is left as a residue, some of which is used for fodder feeding and a large amount of which is just burned by the farmers .This burning off practice is very common in the country because it is the cheapest way in which farmers can rid of the waste material, It can be seen that every year our national capital gets into a cover of smog because of burning of parali (rice straw). Scientists have understood the potential of using rice straw natural fiber in place of wood fiber in various uses, hence many experimental labs and commercial research is being conducted in this field and a lot of startups are also being initiated on this. Various composites are being made and their properties are being tested in various parts of the world. These composites are mainly termed as green composites. These green composite have great potential in preventing our environment, giving sustainable replacement towards use of plastic, wood and all other materials in industrial use.

Polyethylene is a model for semicrystalline polymers that provides the option to vary crystallinity within wide ranges and then to establish relationships between structure and mass and charge transport properties. Three different topics are covered: diffusion of n-hexane in polyethylene, extensive penetrant uptake kinetics, swelling and the design of a novel sensor, and finally electrical conduction in polyethylene, a field important to modern distribution of electric power (HVDC). This feature article presents past and ongoing studies at KTH Royal Institute of Technology using a variety of experimental methods and computer-aided simulation and modelling., QC 20230615

Manufacturers of saw chains continuously strive to increase the performance of their products by reducing cutting times and minimising the energy consumption required for cutting. However, the evaluation process through testing is problematic as several uncontrollable factors impact the results. A large source of uncontrollable factors is the material used as a workpiece. Historically, wood has been used as a workpiece material since it is often what the end user will use it for. As a natural material, each stem contains a unique structure and can have a high variation in mechanical properties. Consequently, the analysis of older cutting efficiency is problematic since the result is linked to the specific stem being sawn, which is destroyed during the testing process. The current work aims to improve the repeatability of these tests by increasing the understanding of which material characteristics and material properties impact the variance during cutting efficiency measurements. An experiment was performed using pine as a workpiece material. It was found that the wood structure, density and hardness or moisture content could explain approximately 80% of the variation in the final tests. A more homogeneous material polyethylene was used to explore if a decrease in variation within these factors resulted in lower variance between cutting efficiency results. The variance between results was found to be lowest in pine when knots were excluded. The variance in polyethylene was slightly higher but showed promising evidence for being a suitable alternative material for long-term testing.

Aquest projecte te com a finalitat desenvolupar una mescla polimèrica que permeti fer us adequat i òptim del PET opac reciclat (rPET-O) i d’aquesta manera aconseguir donar-li una segona vida a aquest material. Un dels materials utilitzats es el polipropilè que forma la fase majoritària i continua del sistema. L’altre, es el rPET-O que forma la fase minoritària i discontinua. Amb l’extrusió es va realitzar dues mescles de composició diferent; després, cada mescla es va injectar a dues velocitats diferents. Es vol determinar si la fase secundaria pot actuar com a reforç de la matriu de polipropilè, i quines condicions de composició i processament afavoreixen aquesta microestructura. Per determinar-ho, s’ha realitzat assajos de índex de fluïdesa (MFI), calorimetria diferencial de rastreig (DSC), assajos de tracció y flexió uniaxial i microscòpia electrònica de rastreig (SEM). S’ha comprovat que la mescla es de naturalesa immiscible que forma una estructura bifàsica amb mala adhesió entre fases. Les propietats mecàniques mostren que l’augment de percentatge en pes de la fase minoritària provoca l’augment del mòdul elàstic a la vegada que es redueix la capacitat de deformació degut a la mala adherència entre fases i la aparició de micro-buits. Dit d’una altra manera, l’augment de fase minoritària disminueix la ductilitat del material. Per altra banda, la velocitat d’injecció promou l’orientació de la fase secundaria degut a cisallament entre el motlle i el material durant el procés d’injecció. El que es tradueix en un augment de la resistència a tracció., Este proyecto tiene como finalidad desarrollar una mezcla polimérica que permita hacer un uso adecuado y optimo del PET opaco reciclado (rPET-O) y así conseguir darle una segunda vida a este material. Uno de los materiales usados es el polipropileno que se encuentra en mayor cantidad siendo la fase mayoritaria y continua. El otro, se trata del rPET-O que se encuentra como fase minoritaria y discontinua. Mediante extrusión se ha realizado dos mezclas de distinta composición y, a continuación, cada mezcla ha sido inyectada a dos velocidades distintas. Se quiere determinar si la fase minoritaria puede actuar como refuerzo de la matriz de polipropileno y qué condiciones de composición y procesamiento favorecen esa microestructura. Para ello, se ha realizado ensayos de índice de fluidez (MFI), calorimetría diferencial de barrido (DSC), ensayos de tracción y flexión uniaxial y microscopía electrónica de barrido (SEM). Se ha corroborado que la mezcla es de naturaleza inmiscible que forma una microestructura bifásica con mala adhesión entre fases. Las propiedades mecánicas muestran que el aumento de porcentaje en peso de la fase minoritaria produce un aumento en el módulo elástico a la vez que se reduce la capacidad de deformación debido a la mala adherencia entre fases y la aparición de micro-vacíos. En otras palabras, un aumento del porcentaje de la fase minoritaria disminuye la ductilidad del material. Por otro lado, un aumento de la velocidad de inyección promueve la orientación de la fase secundaria debido al aumento de cizalla entre el molde y el material durante el proceso de inyección. Eso se traduce en un aumento de la resistencia a la tracción., The aim of this project is to develop a polymeric mixture that allows for the appropriate and optimal use of recycled opaque PET (rPET-O) and thus give this material a second life. One of the materials used is polypropylene, which is found in greater quantities and is the majority and continuous phase. The other is rPET-O, which is found as a minority and discontinuous phase. An extrusion process has been used to generate two mixtures of different composition and then each mixture has been injected at two different speeds. The aim is to determine if the minority phase can act as a reinforcement of the polypropylene matrix, and what composition and processing conditions can achieve this microstructure. For this purpose, melt flow index tests (MFI), differential scanning calorimetry (DSC), uniaxial tensile and flexural tests and scanning electron microscopy (SEM) have been carried out. The mixture was found to be immiscible in nature forming a two-phase microstructure with poor interphase adhesion. The mechanical properties show that increasing the weight percentage of the minority phase leads to an increase in the elastic modulus while reducing the deformation capacity due to poor interphase adhesion and micro-voids. In other words, an increase in the percentage of the minority phase decreases ductility of the material. On the other hand, an increase in injection speed promotes the orientation of the secondary phase due to increased shear between the mould and the material during the injection process. This gets an increase in yield strength.

© 2002 American Chemical Society. The research carried out at Universidad Carlos III de Madrid was supported by Consejería de Educación de la Comunidad Autónoma de Madrid (Spain) under the auspices of the Financing Program for Strategic Research Groups. The authors are grateful to Dr. B. Seoane for useful discussions., The annealing effect on coextruded linear low-density polyethylene (LLDPE) films has been investigated by positron annihilation lifetime spectroscopy (PALS). From the continuous positron lifetime distribution found for these films, the size distribution of the free-volume holes in the amorphous phase is calculated, as well as their fractional free volume. Also, diffusivity measurements at 298 K for He, O-2, and N-2 and X-ray diffraction measurements have been performed. The results reveal that annealing induces changes in the hole size distribution and in the amorphous fractional free volume of the films, along with an enhancement of the gas diffusivity. The correlation found between the amorphous fractional free volume and diffusion coefficients agrees with the free-volume model for diffusion in polymers. Moreover, the results show that the probability density function of the free-volume holes has certain influence on the diffusion coefficients, revealing that the impedance factors for diffusion would be controlled by the size distribution shape of the free-volume holes in the amorphous phase., Consejería de Educación de la Comunidad Autónoma de Madrid (Spain), Depto. de Estructura de la Materia, Física Térmica y Electrónica, Fac. de Ciencias Físicas, TRUE, pub

Incorporation of a small content of undecenoic acid is proposed as an approach to introduce polar groups within the macromolecular architecture of high density polyethylene-based materials in order to promote an easier degradation after their useful service life. The influence of these hydrophilic groups during thermo and photo-oxidation processes has been then evaluated by several complementary techniques. In addition to different degradation rates, distinct ratios of oxidized species (lactones, ketones, carboxylic acids, esters and aldehydes) are found depending on: a) the initial material (neat high density polyethylene or ethylene-co-undecenoic acid copolymer); b) the type of oxidation (thermo or photoinduced); and c) the absence or presence of a specific prodegradant additive. An important increase of crystallinity has been observed in the final oxidized samples, indicating that the extent of degradation is rather significant., MICINN, Depto. de Química Orgánica, Sección Deptal. de Química Orgánica (Óptica y Optometría), Fac. de Ciencias Químicas, Fac. de Óptica y Optometría, TRUE, pub

The production of synthetic plastics, especially polyethylene, has reached a crucial level, making highly challenging plastic waste management. This paper aims to elucidate the role of two novel laccase-like multicopper oxidases in polyethylene oxidative degradation based on transcriptomic data from Rhodococcus opacus R7 grown on polyethylene. The purification of the recombinant proteins, LMCO2 and LMCO3 belonging respectively to the three- and two-domains laccase families, showed that they are endowed with different functional features. LMCO2 showed the highest enzyme activity at 65 °C with an optimal pH of 7.0, while LMCO3 exhibited the highest activity at 80 °C at acidic pH. LMCOs showed activity on both phenolic (i.e., 2,6-DMP) and non-phenolic (i.e., ABTS) compounds and they were thermostable. The oxidative activity of LMCO2 and LMCO3 on untreated low-density polyethylene was assessed by combining Fourier transform infrared spectroscopy and gas chromatography coupled with mass spectrometry analyses. Oxidation of PE was recorded within a short time range (24-48 h) and revealed previously not described patterns of alkyl compounds and oxygenated products including ketones, alcohols, and carboxylic acids. Structural analysis of LMCO2 and LMCO3 together with density functional theory calculations allowed to identify structural and electronic elements presumably involved in the oxidation of polyethylene.

RILEM TC-279 WMR task group TG 1 studied the performance of waste Polyethylene (PE) in bituminous binders and bituminous mixtures. Several laboratories participated in this study following a common protocol. Locally sources aggregates and bituminous binder and same source of waste PE were utilized. The binder experiments showed that at high temperatures, using MSCR tests, PE modified blends had better resistance to permanent deformation in comparison to the non modified binder. Whereas at intermediate temperatures, using the LAS tests, fatigue performance of the PE blends could withstand more loading cycles under low strains; however, it could sustain less loading cycles under high strains due to the increase in brittleness. Dry process was used for the mixture experiments in order to bypass the stability and inhomogeneity experience that was observed at the binder scale. The PE modified mixtures showed improved workability and increased strength. The higher the PE dosage, the higher the ITS increase with respect to the values measured for the control materials (i.e., without any plastic waste) thanks to the improved cohesion of the plastic modified mastic. The stiffness experiments tended to show an improved performance with a lower time dependence and a higher elasticity when plastic was added. The cyclic compression tests demonstrated a reduced creep rate along with a higher creep modulus thanks to the addition of PE; similar conclusions can be drawn from the experimental findings coming from wheel tracking test. Furthermore, acceptable and often improved moisture resistance was observed for PE modified materials., Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public., Pavement Engineering

Microplastics, measuring less than 5 mm, are pervasive environmental pollutants raising concerns about their toxic effects on terrestrial ecosystems, especially earthworms.A comprehensive toxicological evaluation of polyethylene microplastics on earthworms will be beneficial for determining the detrimental impacts of these ubiquitous pollutants on soil ecosystem. Therefore, in the present study, the best representative soil organism, earthworms (Eisenia fetida), were opted for examining the toxicological effect of polyethylene microplastic. E. fetida were subjected to different concentrations of polyethylene microplastic (200, 400, 600, 800, and 1000 mg/kg) in soil and randomly picked out on days 7 to 56. Earthworms exposed to higher concentration of polyethylene (1000 mg/kg of artificial soil) showed a significant reduction in body weight and cocoon formation after 35th days of incubation. A consistent decrease in the concentration of carbohydrates, lipids, and protein was observed when the worms were exposed to the higher concentration of polyethylene. Further, antioxidant enzymes like superoxide dismutase, glutathione S-transferase, peroxidase, catalase, and malondialdehyde were determined for antioxidant stress.Exposure of 200 mg/kg to 1000 mg/kg of artificial soil caused a prominent amplification in the build-up of malonedialdehyde (a biological marker of oxidative stress) by 1.29-fold. It also considerably augmented the activity of the antioxidant enzymes viz., glutathione S-transferase (1.54-fold), superoxide dismutase (1.51-fold), peroxidase (1.25-fold), and catalase (1.87-fold). The present study's findings provide a new understanding of the toxic effect of microplastic on earthworm E. fetida, presenting a foundation for its risk evaluation on soil ecosystems and non-target biological toxicity.

Tato bakalářská práce se věnuje studiu změny volné povrchové energie polyethylenu v čase po úpravě koronou. V teoretické části této práce je popsáno povrchové napětí, volná povrchová energie, měření kontaktního úhlu, způsoby stanovení a vyhodnocení volné povrchové energie pevných materiálů a také typy povrchových úprav polymerních materiálů. V experimentální části této práce je prováděno vyhodnocení volné povrchové energie polyethylenu na základě naměřených hodnot kontaktních úhlů u čtyř kapalin, kontaktní úhel kapalin byl měřen metodou přisedlé kapky. Z naměřených hodnot byla určena volná povrchová energie metodou Owens, Wendt, Rabel a Kaelble (OWRK). Změna volné povrchové energie byla sledována v různých časových intervalech od koronování a při různých dávkách korony., This bachelor's thesis is focused on the study of the change in the surface free energy of polyethylene over time after corona treatment. The teoretical part of this thesis describes surface tension, free surface energy, measurement of the contact angle, methods of determining and evaluating the surface free energy of solid materials, as well as types of surface treatments of polymer materials. In the experimental part of this work, the free surface energy of polyethylene is evaluated based on the measured values of the contact angles of four liquids. The contact angle of liquids was measured by the sessile drop method. The free surface energy was determined from the measured values using the Owens, Wendt, Rabel and Kaelble (OWRK) method. The change in free surface energy was monitored at different time intervals from coronation and at different corona dosages., Fakulta chemicko-technologická, doc. Ing. Tomáš Syrový, Ph.D. - Jak je důležitá korona v tiskovém stroji? Na jakou hodnotu je schopna korona ve stroji fólii upravit? prof. Ing. Michal Veselý, CSc. - Proč je VPE na vrchní a spodní straně odlišná? Jak jste zvažovala směrodatnost odchylek při výpočtech? ing. Jan Vališ, Ph.D. - Sledovala jste vliv umístění vzorků? Komise se shodla, že výsledky plagiátorské kontroly byly adekvátně vysvětleny., Dokončená práce s úspěšnou obhajobou

L'objectiu d'aquest projecte consisteix en la preparació de dues composicions de mescles de PP/rPET-O (80/20 i 70/30 en wt.%) utilitzant el procés d'extrusió reactiva, el qual s'integra un extensor de cadena (Joncryl®) en el rPET-O, obtenint un material denominat REx-rPET-O. Posteriorment les mescles s'injectaran a dues velocitats diferents (60 i 200 cm³/s). Mitjançant Microscòpia Electrònica d'Escombratge s'analitza la morfologia obtinguda, a través de Calorimetria Diferencial d'escombratge, s'han identificat les transicions tèrmiques i es caracteritzaran les propietats reològiques de les mescles mitjançant reometría dinàmica. Posteriorment, el seu comportament mecànic ha estat avaluat mitjançant assajos de tracció, flexió i treball essencial de fractura. L'anàlisi morfològic va revelar una estructura bifàsica en les mescles estudiades, sense interaccions entre les fases. S'ha observat que l'augment del percentatge de cristal·linitat està relacionat amb l'addició de l'extensor de cadena, que resulta en un increment del mòdul d'emmagatzematge i de la viscositat complexa. La inclusió de la fase dispersa REx-rPET-O provoca que el polímer presenti major resistència, però menor ductilitat. En quant al treball essencial de fractura, s'ha observat una tendència general a la disminució dels termes de treball essencial i treball no essencial a mesura que s'incrementa el percentatge de REx-rPET-O, cosa que suggereix una contribució limitada del reforç proporcionat per la morfologia fibril·lar en les provetes. Utilitzant totes les tècniques d’anàlisis esmentades, es conclou que l’ecomescla 80PP/20REx-rPET-O, concretament la proveta injectada a 200 cm³/s, ha presentat millors propietats tant tèrmiques com reològiques i mecàniques., El presente proyecto se centra en la preparación de dos composiciones de mezclas de PP/rPET-O (80/20 y 70/30 en wt.%) utilizando el proceso de extrusión reactiva, proceso durante el cual se modifica el rPET-O con la adición de un extensor de cadena (Joncryl®), obteniendo un material denominado REx-rPET-O. Posteriormente las mezclas se inyectarán a dos velocidades distintas (60 y 200 cm3/s). Se utilizó Microscopía Electrónica de Barrido se analiza la morfología obtenida, a través de Calorimetría Diferencial de barrido se han identificado las transiciones térmicas y se caracterizarán las propiedades reológicas de las mezclas por medio de reometría dinámica. Posteriormente, su comportamiento mecánico ha sido evaluado a partir de ensayos de tracción, flexión y trabajo esencial de fractura. El análisis morfológico reveló una estructura bifásica en las mezclas estudiadas, sin interacciones entre las fases. Se ha observado que el aumento del porcentaje de cristalinidad está relacionado con la adición del extensor de cadena, que resulta en un incremento del módulo de almacenamiento y de la viscosidad compleja. La inclusión de la fase dispersa REx-rPET-O provoca que el polímero presente mayor resistencia, pero a su vez una menor ductilidad. En cuanto al trabajo esencial de fractura, se ha observado una tendencia general a la disminución de los términos de trabajo esencial y trabajo no esencial a medida que se incrementa el porcentaje en peso de REx-rPET-O, lo cual sugiere una contribución limitada del refuerzo proporcionado por la morfología fibrilar en las probetas. Utilizando todas la técnicas de análisis mencionadas, se concluye que la ecomezcla 80PP/20REx-rPET-O, concretamente la probeta inyectada a 200 cm3/s, ha mostrado mejores propiedades tanto térmicas como reológicas y mecánicas., The present project focuses on the preparation of two compositions of PP/rPET-O blends (80/20 and 70/30 in wt.%) using the reactive extrusion process, a process during which the rPET-O is modified with the addition of a chain extender (Joncryl®), obtaining a material called REx-rPET-O. Subsequently, the blend will be injected at two different speeds (60 and 200 cm3/s). Scanning Electron Microscopy was used to analyse the morphology obtained, Differential Scanning Calorimetry was used to identify the thermal transitions and the rheological properties of the blends were characterized by means of a dynamic rheometer. Subsequently, their mechanical behaviour has been evaluated from tensile, flexural and essential fracture work tests. Morphological analysis revealed a biphasic structure in the studied blends, with no interactions between the phases. It has been observed that the increase in the percentage of crystallinity is related to the addition of the chain extender, resulting in an increase in the storage modulus and complex viscosity. The inclusion of the REx-rPET-O dispersed phase causes the polymer to exhibit higher strength, but in turn lower ductility. As for the essential work of fracture, a general tendency for the essential work and non-essential work terms to decrease as the weight percentage of REx-rPET-O increases has been observed, suggesting a limited contribution of the reinforcement provided by the fibrillar morphology in the specimens. By using all the above-mentioned analysis techniques, it is concluded that the 80PP/20REx-rPET-O ecoblend, specifically the specimen injected at 200 cm3/s, exhibited better thermal as well as rheological and mechanical properties.

The interaction of microplastics (MPs) and heavy metals (HMs) can lead to aggravation of detrimental effects in the plants, animals, and even human beings. Keeping this in view, the present study was designed to assess the combined toxic effects of polyethylene MPs (PE- MPs) and cadmium ( Cd) on germination indices and seedling growth of soybean (Glycine max). Particle sizes of 13 and 6.5 mu m and six treatments (control, Cd, 6.5 mu m PE, 6.5 mu m PE + Cd, 13 mu m PE, and 13 mu m PE + Cd) were set to simulate the effects of PE-MPs and Cd on the growth of soybean when used alone or in combined form. As compared to the control, 6.5 mu m PE treatment showed significant effect on most of the germination indices, i.e., decrease in the germination index by 31%, 44% decrease in the vigor index, and 28% decrease in germination rate whereas mean germination time showed no significant differences. Treatment of smaller-size PE-MPs and Cd significantly inhibited both dry and fresh weights. All treatment groups resulted in significant effect on catalase, peroxidase, and superoxide dismutase activities of seedlings depicting adverse effects of interaction of PE-MPs and Cd. Our findings demonstrated the phytotoxicity of PE-MPs and Cd in G. max, and it would lead to serious implications in human beings. Our study is important as it provides preliminary information regarding MP absorption and their accumulation in different levels of food chain. It can also form the basis for future research on single the combined effects of different types and sizes of MPs and heavy metals on the terrestrial plants.

Cílem diplomové práce byla příprava směsných kultur kvasinky Candida albicans a Candida guilliermondii s bakterií Pseudomonas aeruginosa, jejich společná inkubace na abiotickém materiálu a kvantifikace vzniklého biofilmu pomocí real-time PCR. Byla sledována koncentrace vyizolované DNA a její zastoupení bylo vzájemně porovnáno mezi jednotlivými kmeny kvasinek a bakterií. Současně byl zhodnocen společný růst kvasinek a bakterií na polymerech., The aim of the thesis was the preparation of mixed cultures of Candida albicans and Candida guilliermondii with Pseudomonas aeruginosa, their joint incubation on abiotic material and quantification of the resulting biofilm by real-time PCR. The concentration of the isolated DNA was monitored and its abundance was compared between yeast and bacterial strains. At the same time, the mutual growth of yeast and bacteria on polymers was evaluated., Fakulta chemicko-technologická, 1. Prezentace výsledků diplomové práce. 2. Diskuze k posudkům vedoucího a oponenta diplomové práce. 3. Studentka zodpověděla všechny dotazy a připomínky k DP., Dokončená práce s úspěšnou obhajobou

Fishing nets are mainly constituted of Polyethylene (PE), Polyamide, Polyethylene terephthalate (PET), Polypropylene (PP), and Nylon. While new, these plastics exhibit pristine mechanical performance but lose it as they age. But what about their metal adsorptive performance? Literature finds that plastics like PET and PVC accumulate Al, Cr, Mg, Fe, Co, Ni, Zn, Cd, and Pb, even when exposed to very low concentrations. This is mainly true for aged PVC (Kedzierski et al. Adsorption/desorption of Micropollutants. Mar Pollut Bull. 127:684–694, 2018). In this study, we look at the effect of age on the properties of fishing nets, including their capacity to adsorb metals. Because fishnets are in great part constituted by PE, we used standardized PE pellets as our reference. In calorimeter signaling, we observed that end-of-life fishing nets display a very different differential scanning calorimetry (DSC) pattern; both new and old fishing nets are very different from standardized PE polymer. Preliminary results show that Cr, Cu, Pb, and Se adsorption onto fishing nets occurs in the first 10 min to 6 h of exposure (24 h for Se). The maximum uptake was registered at 11 mg Cr kg‒1, 38 mg Cu kg‒1, 27 mg Pb kg‒1, and 15 mg Se kg‒1. All these concentrations refer to old end-of-life PE fishing nets, where new, unused PE fishing nets adsorb 2–20 times less (Old in this chapter refers to used fishing nets. The term is not attempting to attribute a particular life span/age to the nets). A comparison to different EU directives that regulate metal content in plastics for different end-uses shows that the old end-of-life PE fishing nets, after exposure to heavy metals, do not meet the regulations for hazardous waste. We believe that Greenlandic old waste fishing nets can be used to clean the wastewater, or metal-contaminated water, in Greenland and eventually, the rest of the world.

241 p. (eusk.) 238 p. (eng.), Lan hau itsasoko poli(tereftalato etileno) hondakinen (PET-m) birziklapenean zentratzen da, hondakin kutsagarri honi bigarren bizitza bat eman ahal izateko. 1. Kapituluan sarrera eta 2. Kapituluan erabilitako material eta metodoen azalpena egiten da. 3. Kapituluan hainbat PET lagin aztertu dira, hala nola PET lehengai gordina eta post-kondentsatua, eta kontsumo osteko hiri-hondakinak eta itsasoko PET hondakinak. Degradazioaren eragina aztertzeko hondakinen karakterizazioa burutu da. 4. Kapituluan, itsasoko PET hondakinak balorizatzeko metodo konbentzionalenak erabili dira: birziklatze termo-mekanikoa eta aprobetxamendu energetikoa. Birziklatzean gerta litezken degradazioak ere aztertu dira. 5. Kapituluan, itsasoko PET hondakinen birziklatze kimikoa aztertu da, oso degradatua dagoen PETaren balorizazio alternatiba onena bezala, PET-m hondakinentzat. Birziklatze kimikoa proposatzeko, glikolisi erreakzioa erreaktore itxi batean optimizatu da, errendimendu handia lortuz erreakzio-denbora oso baxuan eta produktua karakterizatu da. 6. Kapituluan, biooinarritutako eta birziklatutako PU termoplastikoen sintesia egin da, eta, horretarako, makrodiol bioonarritu bat, 5. Kapituluan lortutako BHET birziklatua eta HDI erabili dira. Era berean, sintetizatutako TPUen karakterizazioa egin da, BHET komertziala erabiliz sintetizatutako TPUekin alderatuz. Azkenik, sintetizatutako TPUen birziklagarritasun termo-mekanikoa zein kimikoa aztertu da. 7. Kapituluan, biooinarritutako eta birziklatutako PU termoegonkorrak sintetizatu dira. Horretarako errizino-olio jatorriko poliol baten, BHET birziklatuaren eta pMDIren erlazio desberdinak erabili dira. Helburua osagai berriztagarri/birziklatuen ehuneko handi bat duten PU termoegonkorrak sintetizatzea izan da, itsasoko PET hondakinetatik lortutako BHET birziklatuari balio erantsia emanez. Era berean, sintetizatuko PU termoegonkorren karakterizazioa egin da, haien birziklagarritasun kimikoaren azterketarekin batera. 8. Kapituluan, tesi honen pro

The lack of anion exchange membranes (AEMs) that possess both high hydroxide conductivity and stable mechanical and chemical properties poses a major challenge to the development of high-performance fuel cells. Improving one side of the balance between conductivity and stability usually means sacrificing the other. Herein, we used facile, high-yield chemical reactions to design and synthesize a piperidinium polymer with a polyethylene backbone for AEM fuel cell applications. To improve the performance, we introduced ionic crosslinking into high-cationic-ratio AEMs to suppress high water uptake and swelling while further improving the hydroxide conductivity. Remarkably, PEP80-20PS achieved a hydroxide conductivity of 354.3 mS cm−1 at 80 °C while remaining mechanically stable. Compared with the base polymer PEP80, the water uptake of PEP80-20PS decreased by 69 % from 813 % to 350 %, and the swelling decreased substantially by 85 % from 350.0 % to 50.2 % at 80 °C. PEP80-20PS also showed excellent alkaline stability, 84.7 % remained after 35 days of treatment with an aqueous KOH solution. The chemical design in this study represents a significant advancement toward the development of simultaneously highly stable and conductive AEMs for fuel cell applications.

Layered composites of monolayer graphene and polymers have drawn significant research attention with extensive application scenarios. Transferring monolayer graphene onto polymer surfaces efficiently has been a fundamental issue in determining the performance of the composites. Despite considerable efforts in the past decade, how to optimally trade off between high-quality graphene transfer and operational convenience still remains challenging. Here we present a novel method allowing the direct transfer of wafer-sized monolayer graphene onto polyethylene membrane surfaces by harnessing van der Waals (vdW) interaction. Use of intermediate, glue, electricity, vacuum, heat, pressure or pre-treatment is not required. It allows preparing graphene/polymer composite membranes in a rapid and clean manner, which is also easy to be scaled up. By analyzing post-strain cracks of graphene, the graphene-polyethylene intrinsic interface shear strength was quantified as 9.52 MPa. Eventually, a kind of ultrathin graphene/polymer composite membrane was prepared with high transparency (>90%), low thickness (<200 nm), smooth surface (<17 nm roughness) high porosity and decimeter sizes. Furthermore, complex-surface transfer, simultaneous double-sided transfer, and facile patterning transfer were readily achieved, confirming the versatility of this transfer method. This newly developed vdW transfer method provides an insightful understanding of the graphene-polymer interfacial interaction and a facile approach to preparing monolayer graphene/polymeric composite membranes.

Measuring the photosynthesis of entire tree crowns and pulse labelling trees with 13CO2 are valuable approaches to study carbon acquisition, transfer, and allocation; however, it is challenging for trees in the field. The objective was to develop and field test large chambers (35 - 45 m3) that enclosed the entire crown of a tree, provided a reliable estimate of tree crown photosynthesis, and ensured efficient 13CO2 labelling. The chambers, made of transparent polyethylene film pulled tightly over a frame, were equipped with an air conditioner, fans, and air blowers. Air temperature, relative humidity, and photosynthetic photon flux density were measured outside and inside each chamber. Six of 4-year-old rubber trees (Hevea brasiliensis) were pulsed-labelled with 18 L of 13CO2 in June and October 2016. The mean air temperature inside the chambers was 1.2 °C higher and the relative humidity 8 % lower than the outside air. The crown photosynthesis, calculated from the decrease in the CO2 concentration inside the chamber, was in the range 140 - 249 µmol s–1 and was significantly related to photosynthetic photon flux density, total leaf area of the tree, and average net CO2 assimilation at leaf level. The labelling efficiency, estimated as the ratio of the amount of 13C recovered in the foliage immediately after labelling divided by the amount of 13C delivered to the tree, was in the range 43 - 68 %. The designed chamber was suitable to estimate crown photosynthesis and perform 13CO2 pulse labelling of 5-m-tall trees in the field.

In 2018, only 9% of new plastic on the market was recycled plastic and only 1% was biobased plastic. Due to the environmental benefits of biobased and recycled plastics over fossil plastics, several options to increase their uptake are under investigation and debated. Both financial and regulatory options are possible. This analysis first focuses on determining and explaining the potential carbon footprint reductions achieved by biobased plastics compared to fossil plastics. Secondly, it proposes a methodology, based on the EU’s revised Renewable Energy Directive (RED II) calculations for renewable energy, to calculate the carbon footprint reduction of biobased plastics.

Functionalized polyethylene-based nanocomposites were prepared by in situ polymerization of ethylene with modified or neat MCM-41 nanoparticles (NMCM-41). Two different synthetic approaches were investigated to improve the compatibility between the hydrophobic HDPE matrix and the hydrophilic NMCM-41: (i) incorporation of UA into the polymeric matrix by copolymerization with ethylene, promoted by the zirconocene catalyst under homogeneous conditions, in the presence of pristine NMCM-41; (ii) use of undecenoic acid (UA) as an interfacial agent to obtain decorated NMCM-41 to be used as nanofiller for the in situ ethylene polymerization, catalyzed by Cp2ZrCl2/MAO under supported conditions. The strong polar character of the carboxylic group is expected to either increase the hydrophilicity of the HDPE chains (strategy i) or interact with the NMCM-41 surface and provide an additional link to the polymeric chains via copolymerization of the vinyl group under supported conditions (strategy ii). Although metallocene catalysts have been shown to copolymerize olefins with functional monomers, the presence of oxygen-containing compounds in the reaction media strongly affects the polymerization activity as a result of the interaction of functional groups with the electrophilic active center of the catalyst. Thus, UA was pre-contacted with tri(isobutyl)aluminum (TIBA) prior to its use in the polymerization to reduce the deactivating character of the carboxylic acid groups towards the zirconocene catalyst. The influence of the UA presence on the polymerization behavior of the protection step is discussed, and the polymerization activities observed for the different approaches are compared. In addition, the thermal behavior and structural details of the resulting materials have been characterized. The impact of using neat or functionalized NMCM-41 on the final dispersion within the polymeric matrix is also analyzed, which is correlated with the mechanical performance exhibited by

Polyethylene has become an integral part of our contemporary lives. The neoteric versatile nature of polyethylene is used in constructing various applications. Out of the plastic waste discarded, 60% of the plastic waste enters landfills. The polyethylene discarded in the soil and water on exposure to the environment forms macroplastics (>2.5 cm), mesoplastics (5 mm - 2.5 cm) and microplastics (<5 mm). Microplastics in the water and soil are observed to have lethal and ecotoxicological effects on aquatic and terrestrial organisms. They enter the food chain and permeate into the food that one eats. In order to address this impending concern, the present study aimed to treat plastics to form a degradable, safe and earthy material. The dissolved polyethylene was treated with starch and was made to react with oxidizing agents such as hydrogen peroxide, nitric acid and acetic acid to lower its inert ability to withstand its degradation. The effect of starch and oxidizing agents on dissolved low density polyethylene was subsequently analysed. The analysis of treated polyethylene showed a decrease in its crystallinity percentage by 6.19 and an increase in its functional groups on reaction with solvent trichloroethylene made to react with starch and oxidizing agents. In the present research, tests were conducted to obtain the various methods that can be utilized to reverse the inert ability of polyethylene. The prevailing recycling model that uses antioxidation techniques is counterproductive since it was found that such techniques appeared to make the polyethylene more resistant to further degradation. In this study, the polyethylene was dissolved in the solvents, such as xylene and trichloroethylene, to make the polyethylene more susceptible to reactants and hence a viable model for treating polyethylene.

This work originated from the need to functionalize surfactant-coated inorganic nanoparticles for biomedical applications, a process that is limited by excess unbound surfactant. These limitations are connected to the bioconjugation of targeting molecules that are often in equilibrium between the free aliquot in solution and that which binds the surface of the nanoparticles. The excess in solution can play a role in the biocompatability in vitro and in vivo of the final nanoparticles stock. For this purpose, we tested the ability of common surfactants - monothiolated polyethylene glycol and amphiphilic polymers - to colloidally stabilize nanoparticles as excess surfactant is removed and compared them to newly appearing multidentate surfactants endowed with high avidity for inorganic nanoparticles. Our results showed that monothiolated polyethylene glycol or amphiphilic polymers have an insufficient affinity to the nanoparticles and as the excess surfactant is removed the colloidal stability is lost, while multidentate high-avidity surfactants excel in the same regard, possibly allowing improvement in an array of nanoparticle applications, especially in those stated.

The production of plastic materials has experienced incredible growth over the past decades. Polyethylene constitutes the largest part (25%) of plastic production, finding its application mostly as film in industrial and food packaging and agricultural use. However, since packaging materials are getting increasingly complex, polyethylene waste is nearly always mixed with other polymers, making direct recycling impossible. Compatibilization of polymer blends can be used to convert an immiscible polymer blend into a homogeneous material with synergistic properties. When this compatibilization is carried out inside an extruder, one less reaction step is needed and the material can directly be processed according to its application. This study addresses the reactive compatibilization of recycled LDPE (rLDPE) originating from industrial film waste with its polymer impurities, as well as virgin low-density polyethylene (LDPE)/polyamide 6 (PA6) blends of various compositions through reactive extrusion with PE grafted with MA (PE-g-MA). A literature review was carried out, summarising the current state-of-the-art of reactive compatibilization and reactive extrusion. The composition of the recycled stream was identified through various characterisation methods. Through a wide variety of characterisation techniques, the mechanical properties of the extruded sample pellets were investigated, as well as the mechanical and optical properties of the blown film. The compatibilizing effect on the virgin LDPE/PA6 blends was found to grow in importance with increasing PA6 content. For 1 wt%, the samples did not exhibit any improvement upon compatibilization. The samples containing 5 wt% showed their improvements predominantly in the optical properties. The 10 wt% samples showed large enhancements overall, after being treated with the compatibilizer. Both the optical and mechanical properties of rLDPE saw a significant amelioration as a result of compatibilization. T, Materials Science and Engineering

This systematic review and meta-analysis investigates the prevalence of complications, reoperations (surgeries without implant modifications) and revisions (surgeries with implant modifications) after proximal interphalangeal joint arthroplasty with pyrocarbon, metal-polyethylene and silicone implants. Thirty-four articles investigating 1868 proximal interphalangeal joints were included. Implant-related complications were associated with 14%, 10% and 11% of the pyrocarbon, metal-polyethylene and silicone implants, respectively, yet these rates were not significantly different from one another. Silicone implants showed more finger deviations (3%) and instabilities (2%) compared with the other implants. Reoperations were fewer for silicone arthroplasties (1%) compared with pyrocarbon (7%) and metal-polyethylene implants (10%). The revision rates of 4%, 3% and 2% were similar for pyrocarbon, metal-polyethylene and silicone implants. Our results indicate that silicone implants remain a valuable option for the treatment of stable proximal interphalangeal joints. Surface replacing implants might be better to correct unstable or deviated proximal interphalangeal joints, although they are associated with a higher risk of reoperations.