Search

In this work, we present an experimental study of the primary and secondary relaxations of the semi-crystalline polymer polyethylene naphthalate by modulated differential scanning calorimetry, Thermally Stimulated Depolarization Currents (TSDCs), and Broadband Dielectric Spectroscopy (BDS) and how they are affected by physical aging. Three dipolar relaxation modes can be observed: from slowest to fastest: the primary α relaxation, which vitrifies at the glass transition temperature, Tgα, and two secondary relaxations, named β* and β. Modulated differential scanning calorimetry results show how the secondary β* relaxation also vitrifies, giving rise to an additional glass transition at Tgβ* < Tgα. In fact, the α and β* relaxations can be considered as part of a very broad and distributed relaxation. Its main part is the primary α relaxation with a shoulder at the high-frequency region corresponding to a complex secondary β* relaxation. BDS results about β* can be modeled by a main contribution (β3*) and two additional ones (β1* and β2*) with a weaker dielectric strength. TSDC results show that each single mode of the relaxation has its own glass transition temperature and they are compatible with the structure inferred by BDS. This scenario gives rise to an extended glass transition dually centered in the Tgβ* ∼ 305 K and Tgα ∼ 387 K temperatures. [ABSTRACT FROM AUTHOR]

Understanding polymer transport in nanopores is crucial for optimizing heterogeneously catalyzed processes in polymer upcycling and fabricating high-performance nanocomposite films and membranes. Although confined polymer dynamics have been extensively studied, the behavior of polyethylene (PE)—the most widely used commodity polymer—in pores smaller than 20 nm remains largely unexplored. We investigate the effects of extreme nanoconfinement on PE transport using capillary rise infiltration in silica nanoparticle packings with average pore radii ranging from ∼1 to ∼9 nm. Using in situ ellipsometry and the Lucas–Washburn model, we discover a previously unknown inverse relationship between effective viscosity (ηeff) and average pore radius (Rpore). Additonally, we determine that PE transport under these extreme conditions is primarily governed by physical confinement, rather than pore surface chemistry. We refine an existing theory to provide a generalized formalism to describe the polymer transport dynamics over a wide range of pore radii (from 1 nm and larger). Our results offer valuable insights for optimizing catalyst supports in polymer upcycling and improving infiltration processes for nanocomposite fabrication. [ABSTRACT FROM AUTHOR]

The plastic flow of ultra-high molecular weight polyethylene (UHMWPE) at a frictional interface, which is critical to the wear behavior, was investigated by reactive molecular dynamics simulations. The UHMWPE substrate was found to experience various deformations during the friction process. First, some polyethylene (PE) chains could detach from the substrate because of their rapid movement. Second, the frequent motion of PE chains also resulted in the intermittent formation and breaking of cavities between intermolecular PE chains. These deformations were more obvious on a surface with a convex protrusion, where the plowing effect exacerbated the cavitation and elastic deformation of PE chains. Correspondingly, the plastic flow in turn reconstructed the convex protrusion by displacing the surface atoms on the Fe slab. The plastic flow of PE chains broke the C–C bonds, and the carbon moieties were then chemically bonded onto the metal surface. A rapid change of atomic charge, hence, happened when the bonds broke. Meanwhile, PE chains release short alkyl radicals gradually after bond breakage, indicating gradual wear of the substrate during friction. This work provides molecular insight into the evolution of interfacial microstructure under plastic flow on a UHMWPE substrate. [ABSTRACT FROM AUTHOR]

Post‐consumer plastic film waste often carries organic and inorganic contaminants that challenge recycling processes and affect the quality of recycled products. An effective contaminant removal procedure through washing such single‐used plastic films (SUPFs) can address environmental and waste management concerns. This study compares the efficiency of different washing techniques in reducing SUPF contamination. To evaluate the efficacy of each washing technique, film samples collected from material recovery facilities are individually exposed to friction, ultrasonic‐assisted, and a combination of both washes. Thermal analysis indicates that the polymers' melting temperature, crystallization temperature, and crystallinity remain unaffected by the washing methods, demonstrating method aptness. Confocal laser scanning microscope images show that washing results in a cleaner sample surface. 91% ash reduction during the combined wash treatment indicates a high method efficiency compared to the individual friction and ultrasonic wash procedures. This is further validated by reducing characteristic contaminant IR bands (3600–3000, 1750–1600, and 1100–1000 cm−1). Elements of concern such as Cd, Cr, Hg, and Pb in SUPFs after each washing technique applied conform with regulations (<100 ppm) for packaging products. This research shows the novel ultrasonic washing reduces more contamination than friction with shorter wash times and no surfactants. [ABSTRACT FROM AUTHOR]

Microplastics (MPs)-induced changes in soil nutrient cycling and microbial activity may pose a potential risk to soil ecosystem. Although some studies have explored these topics, there is still a large space for exploration and a relative lack of research on the mechanism by which soil health and its functions are affected by these changes. Thus, this study investigated the effects of polyethylene (PE) MPs with two particle sizes (13 μm and 130 μm) at five concentrations (0%, 1%, 3%, 6% and 10%, w/w) on soil biochemical properties and ecosystem function. The findings revealed that the exposure to 13 μm MPs significantly reduced soil respiration (Res) rate, β-glucosidase (Glu) and catalase (CAT) activity, which accompanied with enhanced urease activity and decreased soil pH, available phosphorus (AP), dissolved reactive phosphorus (DRP), dissolved organic carbon (DOC) and available potassium (AK) content in most cases. However, 130 μm MPs exerted negligible influence on the DOC and DRP content, Glu and CAT activity. High concentrations of 130 μm MPs significantly reduced soil pH, total dissolved nitrogen (TDN), AP and AK content, but significantly increased soil Res rate. Overall, soil ecosystem function was significantly reduced by the addition of MPs. The Res rate, soil AP and DRP content and Glu activity were the most important predictors of soil ecosystem function. We found that the risk posed by MPs to soil ecosystem function was dose-dependent and size-dependent. These findings underscore that MPs can alter soil functions related to soil nutrient cycling and provide further insights into MPs behavior in agroecosystems. [ABSTRACT FROM AUTHOR]

The performance of incompatible blends is strongly depended on their morphology and interfacial properties that can be controlled by proper compatibilizers. This research systematically investigates the interfacial properties of the binary and the ternary blends based on low-density polyethylene (LDPE), poly(lactic acid) (PLA) and maleic anhydride-grafted polyethylene (PE-g-MAH) through the melt linear viscoelastic rheological behavior of the blends and neat components analyzed by proper rheological models. Moreover, the relationship between rheology, phase morphology and mechanical properties of LDPE/PLA ternary blends with different amounts of PE-g-MAH was studied. In the rheological analyses via the additive rule indicated in the molten state, no consistent interfacial interaction between LDPE and PLA phases is made due to the presence of PE-g-MAH at the interface of the blend. However, the analyses based on the Palierne's model implied that the interfacial tension of compatibilized blends decreases. This not only resulted in improving PLA dispersed phase morphology in the compatibilized blends, but also forming in situ fibrillar composites where the compatibilizer amount was relatively high (5 and 7.5 wt.%). Unlike the molten state, because of the strong interactions between PE and PLA phases of compatibilized blends in the solid state, the tensile mechanical properties, including Young's modulus, strength and elongation-at break, could be reinforced up to 24%, 25% and 90%, respectively. Overall, findings make a profound realization of the amount depended performance of PE-g-MAH as the most common compatibilizer for PE/PLA blends, very helpful not only from scientific viewpoints but also in terms of the blend industry applications. [ABSTRACT FROM AUTHOR]

Polyethylene (PE) is the most abundant plastic waste, and its conversion to hydrogen (H2) offers a promising route for clean energy generation. However, PE decomposition typically requires high temperatures due to its strong chemical bonds, leading to significant carbon emissions and low H2 selectivity (theoretically less than 75 vol % after accounting for further steam‐reforming reactions). Here, we report a mechanocatalytic strategy that upcycles PE into high‐purity H2 (99.4 vol %) with an exceptional H2 recovery ratio of 98.5 % (versus 15.7 % via thermocatalysis), using manganese as a catalyst at a low temperature of 45 °C. This method achieves a reaction rate 3 orders of magnitude higher than thermocatalysis. The marked improvement in H2 recovery ratio is mainly due to metal carbides formation induced by the mechanocatalytic process, which does not catalyze hydrocarbons formation. This work is expected to advance studies of the conversion of polyolefins to high‐purity H2 with net‐zero carbon emissions. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to compare the clinical outcomes, mechanical axis, component positioning, leg length discrepancy (LLD), and polyethylene liner thickness between robotic-assisted total knee arthroplasty (TKA) and conventional TKA in patients with failed high tibial osteotomy (HTO). Methods: A total of 30 patients (30 knees) with failed HTO who underwent TKA using a robot-assisted system between June 2020 and December 2023 were included in this study (robotic group). Additionally, 60 patients (60 knees) with failed HTO who underwent conventional TKA were included as controls (conventional group). Propensity score matching was performed using a 2:1 ratio between the matched participants. The mean follow-up period was 2.1 years in the robotic group and 2.2 years in the conventional group. Clinical evaluations were performed using the Knee Society Score (KSS) rating system. Mechanical axis, component coronal and sagittal positioning, and LLD were evaluated using postoperative radiographs. The thickness of the polyethylene liner was also determined. The mean error values and outliers were calculated and compared between the two groups to determine the accuracy of the mechanical axis, postoperative component positioning, and LLD. Results: The postoperative KSSs in the robotic and conventional groups were not statistically different. The robotic group achieved better accuracy than the conventional group in terms of postoperative mean mechanical axis (1.7° vs. 2.4°, p < 0.05), femur coronal inclination (90.0° vs. 91.6°, p < 0.05), tibial coronal inclination (90.3° vs. 91.3°, p < 0.05), tibial sagittal inclination (90.5° vs. 91.4°, p < 0.05), and LLD (2.2 vs. 7.0 mm, p < 0.05). A significant difference in polyethylene liner thickness was observed between the two groups (p < 0.05). Conclusions: Robotic-assisted TKA showed improved mechanical axis, higher accuracy of component positioning and polyethylene liner thickness, and reduced LLD compared with those of conventional TKA in patients with failed HTO. Further studies with a larger sample size and long-term follow-up are warranted to ascertain whether the accuracy of robotic-assisted TKA can translate into better clinical outcomes and patient satisfaction. [ABSTRACT FROM AUTHOR]

Sugar beet residues (SBR) were converted into thermomechanical pulp (sugar beet pulp, SBP) and compounded with either polylactic acid (PLA) or high‐density polyethylene (HDPE) as matrix. Pressed, thin sheets made with the compounds were placed on soil for 16 weeks outdoors and changes in material properties, including weight losses, monitored. Chloroform extraction showed that proportionally more SBP than PLA was degraded after biodegradation. A reduction in molecular weight of the PLA in composites during processing was determined, which was attributed to moisture in SBP and led to PLA hydrolysis. No further significant reduction in molecular weight of the PLA in composites occurred during outdoor exposure. In case of the HDPE‐SBP composites, results of acid hydrolysis indicated that primarily, the SBP component was degraded. Tensile strength tests, microscopy, FT‐IR spectroscopy and thermal analyses were also performed with the composites. Under the conditions of this study, it was shown that PLA composites with 70% (wt.) of SBP were completely disintegrated before completion of 12 weeks exposure. The addition of SBP to PLA accelerates biodegradation significantly which is an asset for agricultural (mulch films), forestry, horticulture and packaging applications. Highlights: Degradation of composites based on SBP with PLA or HDPE matrix was evaluated on soilAddition of SBP increased weight loss, irrespective of the matrix type during the degradation testsDifferences in material composition over exposure time were analyzedCombination of SBP with PLA enhances biodegradability of compositesSBP offers huge potential as filler in biodegradable polymer composites [ABSTRACT FROM AUTHOR]

Plastics make up a great portion of solid waste that constitutes an emerging threat to the natural environment. Among plastics, polyethylene is the most widely used in the world. In this research, polyethylene materials with different densities designed for packaging applications are the subject of a degradation study. The materials were exposed to simulated solar exposure and were characterized by a combination of analytical techniques to compare both chemical and physical changes, including attenuated total reflection‐Fourier transform infrared spectroscopy (ATR‐FTIR), water contact angle measurements, Raman spectroscopy, grazing incidence X‐ray Diffraction (GIXRD) and nanoindentation tests. The experimental data were systematically analyzed using statistic methods. It was found that the extent of the increase of polar groups, hydrophilicity, crystallinity, and elastic modulus depends on both the density of polyethylene and the duration of UV aging. These changes result from photooxidation and the subsequent structure reorganization occurring in amorphous chains. The implementation of various analytical techniques and statistical analysis provides a holistic understanding of polyethylene degradation behaviors. The knowledge of increased hydrophilicity/polarity in polyethylene is crucial for understanding the fate of plastics in the environment because such polyethylene changes also facilitate the environmental biodegradation on initially non‐polar polyethylene. [ABSTRACT FROM AUTHOR]

Polyethylene is the single largest volume polymer produced globally using Ziegler-type catalysts. Numerous modifications have been reported in search of a better catalyst that can control molecular weight, polydispersity, and branching. In our attempts to identify a suitable imine thiophene-ligated chromium complex, we examined 9 different titanium complexes computationally. The DFT investigations considered barriers for insertion, propagation, and termination by β-H elimination or chain transfer, and identified N-(4-methoxyphenyl)-2-phenyl-1-(thiophen-2-yl)ethan-1-imine(L9) as the most suitable ligand. Subsequently, L9 was prepared in good yield (70%) by condensing 2-phenyl-1-(thiophen-2-yl)ethan-1-one with 4-methoxyaniline. Ligand L9 was treated with early transition metal precursors (Ti, Cr, Zr) to generate a homogenous catalyst. The identity of these catalysts was unambiguously ascertained using a combination of NMR, ICP, FT-IR, UV-Vis spectroscopy, and ESI-MS. The performance of L9-ligated titanium complex [Cat.1] was examined in ethylene polymerization using MMAO as a co-catalyst. Insertion of ethylene was tracked using high-pressure NMR experiments and Cat.1 was found to be active in the polymerization. Ethylene polymerization conditions were optimized to obtain high activity and molecular weight polyethylene. The chromium complex [Cat.2] outperformed the Ti and Zr-derived catalysts with the highest TOF of 6294 mol of PE/mol of Cr/h. Cat.2 produced high molecular weight, high-density polyethylene. SYNOPSIS TOC: Rational designing and synthesis of imine thiophene-ligated Ti, Cr, and Zr-complexes and their performance in ethylene polymerization is presented. [ABSTRACT FROM AUTHOR]

Wood–plastic composites (WPCs) combine the properties of plastics and lignocellulosic fillers. A particular limitation in their use is usually a hydrophobic, poorly wettable surface. The surface properties of materials can be modified using ion implantation. The research involved using composites based on polyethylene (PE) filled with sawdust or bark (40%, 50%, and 60%). Their surfaces were modified by argon ion implantation in three fluencies (1 × 1015, 1 × 1016, and 1 × 1017 cm−2) at an accelerating voltage of 60 kV. Changes in the wettability, surface energy, and surface colour of the WPCs were analysed. It was shown that argon ion implantation affects the distinct colour change in the WPC surface. The nature of the colour changes depends on the filler used. Implantation also affects the colour balance between the individual variants. Implantation of the WPC surface with argon ions resulted in a decrease in the wetting angle. In most of the variants tested, the most significant effect on the wetting angle changes was the ion fluence of 1 × 1017 cm−2. Implantation of the WPC surface also increased the surface free energy of the composites. The highest surface free energy values were also recorded for the argon ion fluence of 1 × 1017 cm−2. [ABSTRACT FROM AUTHOR]

Background: In a previous study we have shown that a cemented vitamin E-doped highly cross-linked polyethylene (VEPE) compared to a conventional polyethylene cup in total hip arthroplasty (THA) has a slightly higher proximal migration but significantly lower wear rates up to 2 years after surgery. In this follow-up study we investigated the same cohort at 6 years. Methods: This was a double-blinded, non-inferiority, randomised controlled trial on patients with osteoarthritis, with a mean age of 66 years. Patients were randomly assigned to receive either the conventional polyethylene cup or the VEPE cup in a 1:1 ratio. The primary endpoint was proximal implant migration of the cup measured with radiostereometric analysis (RSA). Secondary endpoints included wear rate of the cup and patient-reported outcome measurements (PROM). Results: At the 6-year follow-up, 25 patients (11 controls, 14 VEPE) were available for RSA measurements, and we found no statistically significant difference in proximal migration between the VEPE and control groups. The wear rate was significantly lower in the VEPE group compared to controls, 0.03 mm/year and 0.07 mm/year, respectively with a mean difference 0.04 mm, (95% CI, 0.02–0.06 mm). There were no cup revisions and no difference in PROM between the groups. Conclusions: Based on our 6-year results, the VEPE group exhibited no statistical or clinically relevant difference compared to the control group, and the wear rate was significantly lower in the VEPE group. The use of a cemented vitamin E-doped highly cross-linked cup is a good option in total hip arthroplasty. [ABSTRACT FROM AUTHOR]

Introduction: The inelasticity of ceramic bearings might affect primary stability and migration of implants in press-fit total hip arthroplasty (THA). This randomised controlled trial compares migration patterns of the uncemented Delta-TT cup and H-MAX S stem between ceramic and polyethylene liners, up to 5 years follow-up. Methods: Patients receiving primary press-fit THA were randomly allocated to a ceramic (n = 28) or polyethylene (n = 25) liner. Migration was measured using model-based radiostereometric analysis (RSA) at baseline and 1.5, 3, 6, 12, 24 and 60 months postoperatively and compared between groups using mixed models statistical analysis. The focus of this study is on the 2- to 5-year migration of the Delta-TT cup and migration during complete follow-up of the H-MAX S stem up to 5-years. Results: At 5-year follow-up, mean (95% CI) proximal cup translation was 0.56 (0.37–0.74) mm in ceramic and 0.58 (0.25–0.90) mm in polyethylene (p = 0.729). The mean change in adduction was 1.05° (0.27–1.82°) in ceramic and 0.78° (−0.16–1.71°) in polyethylene. Mixed modelling showed that all between-group effects were ⩽0.20 mm for translation and ⩽0.22° for rotation at 5 years postoperatively (p ⩾ 0.23). Mean cup migration between 2 and 5 years was limited (all parameters <0.17 mm and <0.30°). At 5-year follow-up, mean stem subsidence was 2.09 mm (0.89–3.29 mm) in ceramic and 2.55 (0.97–4.12) mm in polyethylene. The mean change in internal rotation was 3.69° (1.98–5.40°) in ceramic and 4.01° (2.20–5.81°) in polyethylene. Most stem migration occurred up to 1.5 months, stabilising afterwards. All between-group effects were ⩽0.75 mm for translations and ⩽1.41° for rotations (p ⩾ 0.26). Conclusions: 5-year migration patterns of press-fit cups and stems were similar between ceramic and polyethylene liners. The Delta-TT cup and H-MAX S stem showed secondary stabilisation and remained stable up to 5 years in both groups, which is promising for long-term survival with both liner types. Clinical trial registration: ClinicalTrials.gov (NCT03093038) [ABSTRACT FROM AUTHOR]

In this work, the rheological properties of four multi-wall carbon nanotubes (MWCNTs)/polyethylene (PE) composites containing 1 wt.% (mPEC1), 3 wt.% (mPEC3), 5 wt.% (mPEC5), and 10 wt.% (mPEC10) MWCNTs prepared by the masterbatch method were investigated and compared with those of the pure PE. The rheological investigation includes strain sweeping, frequency sweeping, stress relaxation behavior, yield stress, characteristic relaxation time, temperature effect on linear viscoelastic behavior, and gel behavior. It is mainly found that (1) the MWCNTs-MWCNTs interaction resulting in MWCNTs network structure in the PE matrix and the MWCNTs-PE interfacial interaction increase the storage and loss moduli of the MWCNTs/PE composite in comparison with those of pure PE; (2) the time-temperature equivalence principle is applicable only for pure PE and mPEC1; (3) for gel behavior of MWCNTs/PE composite at 160–180 °C, the φ g value decreases with the increase of temperature and the highest S g value is obtained at 170 °C. [ABSTRACT FROM AUTHOR]

Plastics are used widely in almost every field of life, but their synthetic and persistent nature makes them harmful for the environment. The aim of this research was to evaluate the degradation abilities of Aspergillus niger, Candida albicans, and Acremonium sclerotigenum on microplastics (MPs). MP pieces of 4 ± 1 mm, including polyethylene, polyethylene terephthalate, and polystyrene, were incubated with fungal inoculums for 30 days. The degradation of treated MPs was determined by biofilm formation, weight loss, scanning electron microscopy (SEM), and Fourier transform analyses. The results indicated that the polyethylene MPs treated with Aspergillus niger exhibited the highest level of biofilm formation (optical density 1.595) and percentage weight loss (16%). In the case of polyethylene terephthalate and polystyrene MPs, Acremonium sclerotigenum and co‐culture showed weight loss of 6% and 10%, respectively. Candida albicans was observed to be the least effective in biodegradation analyses. SEM observation revealed the surface modifications as holes, pits, cracks, and increased roughness in treated MPs. Fourier transform infrared (FTIR) spectroscopy showed that the chemical structure of each polymer exhibited some variations. The study concluded that the fungal strains play an important role in the biodegradation of plastics and can be utilized to mitigate environmental pollution. [ABSTRACT FROM AUTHOR]

Low‐Density Polyethylene (LDPE) reactors have the potential for rupture because of thermal runaway from auto‐accelerating chemistry. Pockets of unmixed, highly reactive, LDPE constituents, called hot spots, are often generated by conditions within the reactor and are the main source of thermal runaway. Because of this, there is a need to define thresholds of hot spot conditions that produce runaway. Computational Fluid Dynamics is used to study an isolated LDPE sphere with varying initial temperature, initial catalyst concentration, and volume to determine which combinations promote thermal runaway. It is found that increasing both initial temperature and initial catalyst concentration increased thermal runaway likelihood, while, counter‐intuitively, hot spot volume has no effect. An LDPE runaway map is provided to quantify the combinations that result in safe reactor operation. This allows manufacturers to make more informed control actions and to determine safe reactor conditions based on local mixture composition and temperature alone. [ABSTRACT FROM AUTHOR]

Polyolefins such as polyethylenes and polypropylenes are the most‐produced plastic waste globally, yet are difficult to convert into useful products due to their unreactivity. Pyrolysis is a practical method for large‐scale treatment of mixed, contaminated plastic, allowing for their conversion into industrially‐relevant petrochemicals. Metal–organic frameworks (MOFs), despite their tremendous utility in heterogeneous catalysis, have been overlooked for polyolefin depolymerization due to their perceived thermal instabilities and inability of polyethylenes and polypropylenes to penetrate their pores. Herein, we demonstrate the viability of UiO‐66 MOFs containing coordinatively‐unsaturated zirconium nodes, as effective catalysts for pyrolysis that significantly enhances the yields of valuable liquid and gas hydrocarbons, whilst halving the amounts of residual solids produced. Reactions occur on the Lewis‐acidic UiO‐66 nodes, without the need for noble metals, and yield aliphatic product distributions distinctly different from the aromatic‐rich hydrocarbons that can be obtained from zeolite catalysis. We also demonstrate the first unambiguous characterization of polyolefin penetration into UiO‐66 pores at pyrolytic temperatures, allowing access to the abundant Zr‐oxo nodes within the MOF interior for efficient C−C cleavage. Our work highlights the potential of MOFs as highly‐designable heterogeneous catalysts for depolymerisation of plastics, which can complement conventional catalysts in reactivity. [ABSTRACT FROM AUTHOR]

In low‐density polyethylene (LDPE) production, low‐molecular‐weight species are used as chain transfer agents (CTAs). They reduce the degree of polymerization, which has an impact on the polymer properties, such as processability. To specifically adjust the product properties, a detailed understanding of the transfer kinetics to CTAs is indispensable. Thus, the transfer activity of various primary, secondary, and tertiary alcohols as well as diols was investigated experimentally between 120 °C and 250 °C at 2000 bar. The results were evaluated using the Mayo and chain length distribution (CLD) method, and the latter was found to give more reliable results. It was observed that the hydroxy group systematically increases transfer activity compared to alkanes. Additionally, a linear increase of transfer activity with the number of hydrogen atoms is found. [ABSTRACT FROM AUTHOR]

Polyolefins such as polyethylenes and polypropylenes are the most‐produced plastic waste globally, yet are difficult to convert into useful products due to their unreactivity. Pyrolysis is a practical method for large‐scale treatment of mixed, contaminated plastic, allowing for their conversion into industrially‐relevant petrochemicals. Metal–organic frameworks (MOFs), despite their tremendous utility in heterogeneous catalysis, have been overlooked for polyolefin depolymerization due to their perceived thermal instabilities and inability of polyethylenes and polypropylenes to penetrate their pores. Herein, we demonstrate the viability of UiO‐66 MOFs containing coordinatively‐unsaturated zirconium nodes, as effective catalysts for pyrolysis that significantly enhances the yields of valuable liquid and gas hydrocarbons, whilst halving the amounts of residual solids produced. Reactions occur on the Lewis‐acidic UiO‐66 nodes, without the need for noble metals, and yield aliphatic product distributions distinctly different from the aromatic‐rich hydrocarbons that can be obtained from zeolite catalysis. We also demonstrate the first unambiguous characterization of polyolefin penetration into UiO‐66 pores at pyrolytic temperatures, allowing access to the abundant Zr‐oxo nodes within the MOF interior for efficient C−C cleavage. Our work highlights the potential of MOFs as highly‐designable heterogeneous catalysts for depolymerisation of plastics, which can complement conventional catalysts in reactivity. [ABSTRACT FROM AUTHOR]

Polyethylene (PE) is the most prevalent type of plastic waste and also the most challenging to depolymerize because of its inert carbon‐carbon (C−C) bonds.[1] High temperature and noble metals are usually required for depolymerization.[2] To avoid using noble metals, costly reagents and harsh reaction conditions, it is worthwhile but challenging to explore new reaction pathways.[3] We report an unprecedented mechanochemical reaction of PE and water to result in shorter‐chain alkanes, alkenes, alcohols, and ketones (Cn, where n≲50), with above 80 % of starting carbon converted into these products, which could be a valuable feedstock for re‐entering chemical value chains. This reaction is driven solely by ball milling, without heating and pressurizing. No costly catalysts are used. Instead, only earth‐abundant Al2O3 was milled with reactants. [ABSTRACT FROM AUTHOR]

Long‐chain polyamides (polyethyleneamides) were prepared from polyethylenes bearing in‐chain carbonyl groups (polyethyleneketones) by the oxime formation and successive Beckmann rearrangement. (Diethylamino)sulfur trifluoride (DAST) was utilized as a promoter, which allowed mild conversion of the oxime group in spite of low solubility of the polymers. The polyethyleneamide exhibited different tensile property compared to a commercial HDPE. [ABSTRACT FROM AUTHOR]

Long‐chain polyamides (polyethyleneamides) were prepared from polyethylenes bearing in‐chain carbonyl groups (polyethyleneketones) by the oxime formation and successive Beckmann rearrangement. (Diethylamino)sulfur trifluoride (DAST) was utilized as a promoter, which allowed mild conversion of the oxime group in spite of low solubility of the polymers. The polyethyleneamide exhibited different tensile property compared to a commercial HDPE. [ABSTRACT FROM AUTHOR]

Fluorescence polarization (FP) assays are widely used to quantify biomolecules, and their combination with microfluidic devices has the potential for application in onsite analysis. However, the hydrophobic surface of polydimethylsiloxane (PDMS)-based microfluidic devices and the amphiphilicity of the blocking agents can cause the nonspecific adsorption of biomolecules, which in turn reduces the sensitivity of the FP assay. To address this, we demonstrated an FP assay with improved sensitivity in microfluidic devices using a polyethylene glycol-based surface modification to avoid the use of blocking agents. We evaluated the effectiveness of the modification in inhibiting nonspecific protein adsorption and demonstrated the improved sensitivity of the FP immunoassay (FPIA). Our study addressed the lack of sensitivity of FP assays in microfluidic devices, particularly for the quantification of low-abundance analytes. [ABSTRACT FROM AUTHOR]

The document is the contents list for an issue of the journal Chemical Communications. It includes articles on various topics such as the synthesis of chiral systems, progress in extractants for actinides and lanthanides separation, and the design of sulfonimide anions for rechargeable lithium batteries. The journal is published by The Royal Society of Chemistry and aims to connect the world with the chemical sciences. [Extracted from the article]

Here, we describe the preparation of bridged ethylene polyethylene oxide (BE‐PEO) surface‐modified silica packing materials for size exclusion chromatography. BE‐PEO surface‐modified silica was hydrolyzed and subsequent 1H nuclear magnetic resonance analysis of hydrolysis products confirmed the successful formation of BE‐PEO bonded surface. Silica particles exhibiting 3 µm diameters and 1000 Å nominal pore diameters were selected as a base material for this work out of the critical need to improve analytical capabilities for the testing of cell and gene therapy drug products. Accelerated high pH aging study revealed significant enhancement in column stability. Multi‐angle light scattering noise measurements showed inordinately lower baseline noise. Moreover, we evaluated the chromatographic performance of BE‐PEO silica‐packed columns through separations of a protein test mixture, DNA ladder, monoclonal antibody‐based therapeutics, and adeno‐associated viruses. BE‐PEO silica columns demonstrated high resolution, high recovery separations that were confirmed to be reproducible and capable of extended column lifetimes and exhibited low ionic and hydrophobic secondary interactions. In summary, BE‐PEO silica particles have yielded a new level of performance, improved base stability, and inherently lower baseline noise. These novel widepore particles will facilitate more sensitive size‐based detection and characterization of large biologics in the form of advanced gene therapy products. [ABSTRACT FROM AUTHOR]

Background: This retrospective study compares the outcomes of unicompartmental medial fixed-bearing knee arthroplasty (mUKA), involving a cemented metal-backed (MB) or an all-polyethylene (AP) tibial component, performed in obese patients with a body mass index (BMI) > 30 with a follow-up of at least 5 years. Methods: The institutional database was mined for primary mUKAs involving an MB or an AP tibial component (MB-UKA and AP-UKA groups, respectively) performed from January 2015 to August 2019. Patient demographics and patient-reported outcome measures (PROMs) were compared and a propensity score matching (PSM) analysis (1:1) using multiple variables was conducted. Results: PSM analysis yielded 37 pairs of obese MB-UKA and AP-UKA patients. At 5 years, the Knee Society Function Score (KSFS) was 75.1 ± 10.6 in MB-UKA and 79.4 ± 9.1 in AP-UKA patients (p = 0.029), and the Oxford Knee Score (OKS) was 38.1 ± 4.4 in MB-UKA and 40.6 ± 5.7 in AP-UKA patients (p = 0.011). Conclusion: At five-year follow-up, in a matched group of obese MB-UKA and AP-UKA patients, the AP-UKA group achieved better KSFSs and OKSs. Both the AP and the MB tibial components were able to bring about a significant improvement of the most widely used PROMs. [ABSTRACT FROM AUTHOR]

A bidentate ligand, 2,3‐dihydro‐2,2‐dimethyl‐7‐benzofuranol (ddbfOH), is used to synthesize the titanium complexes, ddbfOTi(OiPr)3(1) and (ddbfO)2Ti(OiPr)2(2). Combined with diethylaluminium chloride (Et2AlCl) and di‐n‐butylmagnesium (Bu2Mg), complexes 1 and 2 exhibit super high activity towards ethylene polymerization, and giving the ultra‐high molecular weight polyethylene (UHMWPE). After rationally optimizing the experimental conditions, the highest polymerization activity is achieved in both 1/ and 2/Et2AlCl/Bu2Mg catalytic systems (213.6×106 g‐PE⋅mol‐Ti−1 h−1, 142.8×106 g‐PE⋅mol‐Ti−1 h−1). The highest molecular weight (Mv =1905×104) can be achieved under a low polymerization temperature (−30 °C) at the expense of activity (3000 g‐PE⋅mol‐Ti−1 h−1). Additionally, through the investigation of various polymerization conditions on the activity and molecular weight of the catalytic system, we have found that the ratio of the catalyst and cocatalyst has a more significant impact on both activity and molecular weight. [ABSTRACT FROM AUTHOR]

Inflatable pouches are attractive as actuators and structural links in soft robots due to their low deflated profile and high deformation ratio. However, current pouch robot fabrication methods have relatively large minimum feature sizes and multi‐layer fabrication challenges, limiting the integration of mechanisms with many independent degrees of freedom (DoF). A new monolithic prototype fabrication method utilizes inkjet printing of a masking ink layer, which prevents film bonding and thus defines inflatable regions. Multi‐layer inflatable pouches of any planar geometry can be created using thermal fusing, with inter‐layer connections and a minimum feature resolution of 0.3 mm. The multi‐layer fabrication process enables the integration of pouches for bending actuation and structure, pneumatic channels, and external port connections. This high level of integration enables the fabrication of pouch robots with many independent DoFs. Specific examples using four layers of 38 micrometer thick Low‐density polyethylene (LDPE) include 1) a 38 mm‐wide 4‐fingered robot hand with 8 independent DoFs which rotates a cube within its palm and 2) a 138 mm‐long planar continuum manipulator with 10 independent DoFs for pick‐and‐place of a cylinder. These example designs demonstrate the capability of ink‐patterned masking to achieve new levels of functionality for thin‐film pouch robots. [ABSTRACT FROM AUTHOR]

Polymer liners are key components of high-pressure hydrogen storage tanks, and understanding their behaviour under such environments is crucial for safety. This study employs molecular dynamics (MD) simulation to investigate the physical and tensile properties of amorphous polyethylene (PE) under the effects of hydrogen content, pressure, temperature. It is found that hydrogen molecules decrease glass transition temperature by approximately 3%, while pressure have no noticeable impact. Meanwhile, hydrogen molecules enhance diffusivity, while pressure suppresses diffusivity and exhibits a more pronounced impact, resulting in an overall decrease of 44% in diffusivity under high-pressure hydrogen. Tensile stress also increases the diffusivity by 17%. Hydrogen molecules weaken the non-bonded molecular interactions of PE, which reduces the percentage of trans conformation and orientation parameters. Meanwhile, hydrogen also suppresses the internal energy change of PE induced by tensile deformation. Therefore, hydrogen molecules lead to a decrease in tensile properties. Comparatively, pressure causes PE to produce more trans conformations under tension, which improves orientation, entanglement parameters, and the internal energy change of PE, and finally enhances the tensile properties of PE. The effect of pressure surpasses that of hydrogen, which results in an approximately 40% increase in tensile properties under high-pressure hydrogen. This study provides molecular-level insights into the individual and coupled effects of hydrogen and pressure, forming a foundation for predicting polymer behaviour under high-pressure hydrogen conditions. • Hydrogen lowers the T g of PE, while pressure has no noticeable effect. • Hydrogen increases the diffusivity of PE, while pressure reduces it. • Hydrogen weakens PE tensile properties, while pressure improves them. • High-pressure hydrogen lowers T g , reduces diffusivity, and enhances tensile properties of PE. [ABSTRACT FROM AUTHOR]

Bio‐based polymers may present a sustainable, circular way to reduce the environmental impact of plastics because they are produced from biomass that absorbs CO2 during its growth. However, sourcing (type of biomass used and cultivation location), production, and end‐of‐life affect the environmental impact of bio‐based plastics. We assessed the effect of sourcing and end‐of‐life options on the environmental impact of bio‐based high‐density polyethylene (bio‐HDPE) in 31 sourcing scenarios and five end‐of‐life options. Our study found that careful consideration of biomass sourcing (biomass type and production location) and end‐of‐life is needed to optimize the environmental impact of bio‐based plastics. If these aspects are not considered, the environmental impact of bio‐HDPE may exceed that of its petrochemical‐based counterpart. The direct availability of fermentable sugars indicated a lower environmental impact. The production location affected the resources needed for biomass cultivation and the environmental impact of processing due to the energy mix. Recently published guidelines do not allow biogenic carbon to be accounted for during the production stage, but only upon the incineration of the plastic. Our results show that this way of attributing biogenic carbon results in an apparent disadvantage for bio‐based plastics compared to petrochemical‐based plastics. Furthermore, it disadvantaged mechanical recycling of bio‐based plastics compared to incineration, a result out of line with circular economy principles. [ABSTRACT FROM AUTHOR]

As a model of a chemical upcycling process, we have developed a single-metal homogeneous catalytic system to break down persistent polyethylene waste into valuable chemical intermediates. This could ultimately be used to produce important chemical products, including environmentally friendly, biodegradable plastics. In the first step, a slow pyrolysis of polyolefin waste yields oils, containing long-chain olefins as the major components. Then, for the next transformation step, tailored bicyclic (alkyl)(amino)carbene (BICAAC)-Ru olefin metathesis catalysts were used in combination with an alkene isomerization catalyst (RuHCl(CO)(PPh3)3) for the transformation of the pyrolysis oil to propylene via isomerization-metathesis (ISOMET) reaction in ethylene atmosphere. Eventually, translation of the highly efficient single-metal catalyst system enabled ISOMET reaction to a 900 mL reactor setup and repetitive batch experiments could prove the long-term stability of the catalyst system and the highest total turnover number (tTON = 2788 mol propylene per mol olefin metathesis catalyst) reported so far using post-consumer polyethylene waste feedstock. [ABSTRACT FROM AUTHOR]

Crosslinked polyethylene cable is an important equipment in 10 kV distribution system, and its safety is very important. Making scientific judgments on cable repair decisions can help improve the safety and reduce the economic cost. In view of this, a cable risk assessment and repair decision method based on K‑means clustering and random forest(RF) classification model is proposed. The method first defines the risk level and risk degree of the cable based on the insulation status of the cable. Then the K‑means clustering algorithm is used to cluster the multi‑aging index dataset and classify the risk level intervals to build a multi‑aging index risk matrix. Based on the risk matrix of the multi‑aging index, the classification labels corresponding to the multi‑aging index are determined by using the comprehensive weight method. Finally, the classification model of the repair ways of the cables is established and trained based on the RF algorithm, and the selection results of the repair ways are output. The average accuracy of the proposed method reaches 99.70%, achieving rapid and reliable repair decisions for cables. [ABSTRACT FROM AUTHOR]

Waterborne polyurethanes emulsions (WPU) based on polyethylene carbonate diol (PECD) were synthesized, characterized and modified by polypropylene carbonate diol (PPCD) and organosilicon KH-792. The mechanical, thermal and hydrolysis resistance properties of waterborne polyurethanes were comprehensively investigated. The results show that PECD based WPU has very excellent mechanical properties. The tensile strength and the elongation at break the PU was up to 73 MPa and 1040%, which was much higher than that reported for similar types of PPCD-based WPU. It was found that water absorption of PECD based WPU can be decreased dramatically, from 40.9% to 21.1%, after 50% PECD was replaced by PPCD, while tensile strength only decreased from 73.0 MPa to 63.4 MPa. The addition of KH-792 has great influence on PECD based WPU, when 1% KH-792 was added, the water absorption rate decreased from 21.1% to 11.88%, the mechanical strength remained at 63.3 MPa, the WPU film remained transparent after soaking in 80 ℃ hot water for 4 h. [ABSTRACT FROM AUTHOR]

Sardines and anchovies are the most important small pelagic species throughout the Mediterranean, caught mainly by purse-seiners. Their rapid bacterial degradation after capture and storage limits their commercial use and shelf life. Gills are the most vulnerable tissue in fish, harboring bacterial communities which have not been previously investigated in these species. This study examined cultivable bacteria from gills of harvested sardines and anchovies, tanks in which they are stored aboard, and fishing nets on four occasions (twice for both warm and cold seasons). A total of 471 bacteria were isolated, belonging to 74 genera and 163 species by MALDI-TOF MS identification. A number of genera and species identified from fish and surfaces occurred only in the warm or cold season, but a fraction occurred in both seasons. Sardine gills harbored most of the isolated bacteria (254), belonging to 53 genera and 111 species, as opposed to anchovy with 120 strains, belonging to 30 genera and 64 species. A diverse cultivable bacterial community consisting of 17 species was isolated exclusively from the polyethylene surfaces of nets and tanks. This finding is significant regarding their potential migrations between planktonic and sessile lifestyles. Possible contamination and cross-contamination are likely to increase with the rise in ambient and seawater temperature during the hauling and sorting of fish in the tanks. The food safety risks stem from pathogens and fish spoilage bacteria on both the fish and the surfaces of fishing nets and storage tanks. [ABSTRACT FROM AUTHOR]

Enhancing the degradability of polyethylene plastics could provide a potential solution to the overwhelming crisis of plastic waste. Conventional studies have focused on the degradation of polyethylene thin films. This study investigated UV-induced photo-degradation according to ASTM D5208-14 in polyethylene sheets with thicknesses ranging from 0.4 to 1.2 mm. The impacts of sample thickness, metal pro-oxidants, polyethylene resin types and foaming were explored through the characterization of the carbonyl index, molecular weight, tensile properties and crystallinity. As pro-oxidants, single iron or manganese stearate demonstrated a concentration-dependent trend in accelerating the photo-degradation of polyethylene sheets. The thickness, foaming and resin type—such as low-density polyethylene (LDPE) and high-density polyethylene (HDPE)—significantly impacted the rate of photo-oxidation. Thick polyethylene sheets (1.2 mm) exhibited a heterogenous and depth-dependent degradation profile. As the photo-degradation progressed, the enhanced crystallinity, reduced UV transmittance and formation of crosslinks were able to prevent further oxidative cleavage of the polyethylene chain. This study investigated the time course and factors affecting the photo-degradation of polyethylene sheets, which could provide insights into the formulation design of photo-degradable polyethylene plastics. [ABSTRACT FROM AUTHOR]

This study analyzed the possibility of using plant-originated waste materials (black and green tea dust) as functional polyethylene fillers. The dependence between the size of the filler particles and their antioxidant potential is discussed. Six fractions were selected: below 50 µm, 50–100 µm, 100–200 µm, 200–400 µm, 400–630 µm and 630–800 µm. Significant differences between the effect of particle size and the antioxidant properties of black and green tea were found using the extraction method to analyze antioxidant activity (DPPH method) and total phenolic content (Folin-Ciocalteu method), suggesting a higher potential for using green tea as a filler with antioxidant properties, as well as the benefits of finer active filler distribution. Biomass waste fillers were mixed with low-density polyethylene LDPE SEB 853 I'm Green®, Braskem. Those samples were oxidized at 100 °C for 5 and 15 days to investigate the radical scavenging properties of fillers in composites. Fourier transform infrared spectroscopic studies show that the addition of both types of filler prevents the thermo-oxidation of polyethylene for 5 days. After 15 days, all samples except the BTW 400–630 and 630–800 µm exhibited oxidation. The mechanical properties of the LDPE and its' composites were tested, and we noted an increased brittleness of neat LDPE after thermal oxidation. The addition of black tea particles above 100 µm in size prevents this behavior. [ABSTRACT FROM AUTHOR]

The influence of carbon nano fiber (CNF) along with organically modified nanoclay (OMMT) on the final properties of high density polyethylene (HDPE) hybrid nanocomposites has been investigated. The hybridized nanocomposites were prepared in a twin screw extruder by melt mixing to achieve better dispersion. The effect of nano fillers on the mechanical, thermal, rheological, and morphological properties has been reported. The incorporation of OMMT along with CNF slightly improved the mechanical properties of the resultant hybrid nanocomposite due to the good adhesion between the filler and matrix. On the other hand, as shown in DSC results, increasing reinforcing filler quantity has no significant influence on the thermal properties such as melting and crystallization temperatures. Thermogravimetric analysis (TGA) results have shown that increasing filler content in the hybrid nanocomposite matrix has enhanced drastically the thermal stability of the neat HDPE. Similarly, the rheological behavior of the hybrid system showed significant increase in the viscosity due to the synergetic effect. A marginal increase in moduli and complex viscosity was observed in the hybrid system, while loss tangent was found to be decreased due to the increase in the stiffness. The morphological features of nanocomposites were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The nanoscale images showed the well dispersion of filler nanoparticles without any prominent aggregation, which further indicates the compatibilizing ability of nanofillers within the HDPE matrix. [ABSTRACT FROM AUTHOR]

The escalating population growth has spurred a demand for increased oilseed production, necessitating urgent attention. However, the expansion of saline‐affected regions posed a significant obstacle to maintain peanut productivity in these areas. Thus, to tackle the productivity decline in saline‐affected regions, we investigated whether substituting polythene mulch with straw mulch, as part of an agronomic management strategy, could mitigate the rapid decrease in peanut productivity. Three mulching methods (control, polythene mulch and straw mulch) were employed to cultivate the crop (cv. TG 37A) under salinity levels of 0.5, 2, 4 and 6 dS m−1. As salinity levels increased, there was a notable decrease in germination percentage, growth, yield and biochemical characteristics, including pod and haulm yields were reported. Despite salinity reduced free amino acids and oil content, it exhibited significant increase in protein and sugar content. Saline irrigation water led to a reduction in pod yield, haulm yield and oil content by 24.67%, 23.84% and 5.07%, respectively, at a salinity level of 6.0 dS m−1 compared to the control with 0.5 dS m−1 salinity. Moreover, straw mulching resulted in a boost in pod yield, haulm yield and oil content by 30.09%, 4.83% and 1.75%, respectively, compared to the control. The reduction in pod yield and oil content under the interaction of mulching and salinity was 46.44% and 6.87% at M0S6, 21.42% and 4.44% at M1S6, and 7.55% and 3.87% at M2S6 compared to M0S0, M1S0 and M2S0, respectively. A similar trend was also observed in 100‐pod weight, 100‐kernel weight and shelling percentage. Accordingly, it was concluded that the declining trend in all attributes under straw mulching at various salinity levels surpassed polythene mulching, ensuring superior peanut production under salinity stress conditions. [ABSTRACT FROM AUTHOR]

Plastic products are used in large quantities. However, the fact that plastics do not degrade in nature for many years causes environmental pollution. Addressing this issue, the study focuses on recycling the widespread high-density polyethylene (HDPE) plastic waste. In this study, HDPE waste was collected randomly from the environment, mirroring real-world scenarios. Then, the waste was transformed into granules. Afterward, washing and drying processes were carried out. HDPE filaments of different linear densities were successfully produced from the waste plastic granules. Tensile tests revealed that the breaking strength of the filaments from waste plastic was lower than that of virgin HDPE filaments, highlighting the challenges of recycling. Hybrid yarns were formed by twisting the filaments with cotton yarn to improve the mechanical properties of the filaments from waste plastic. Remarkably, statistical analysis demonstrated that the breaking load values of the hybrid yarns from waste plastic were statistically equivalent to those made from virgin polymer. This outcome indicated that the hybrid yarns made from waste HDPE plastic were as strong as those made from virgin HDPE polymer. In addition, both hybrid yarns exhibited a breaking load 36% higher than the reference extra-twisted cotton yarn. The hybrid yarn formation made filaments produced from waste plastic a valuable component of the high-strength hybrid yarn. Overall, this study shows that recycling HDPE plastics can lead to the production of high-strength hybrid yarns, which can contribute to reducing plastic waste pollution. [ABSTRACT FROM AUTHOR]

The kinetics of polymerization of epoxy resin ED-20 cured with a polyethylene polyamine hardener modified with silicone rubber, tris(trimethylsiloxy) phenylsilane, octamethyl cyclotetrasiloxane is studied. A more rapid decrease in the amount of epoxy groups in systems modified with silicon-contained additives during polymerization is observed. A differential equation describing the change in changes in the concentration of epoxy groups with the polymerization time is proposed. The found exact solution to the proposed equation describes adequately the experimental data. The modification of epoxy binder reduces the time and temperature of the maximum heat release during the curing. The modification with the addition of tris(trimethylsiloxy) phenylsilane leads to the maximum increase in heat release. A differential equation describing the change in the heat release temperature with the curing time is formulated. The exact solution to the equation formulated is found, which is applied to estimate the curing end time of the compositions. [ABSTRACT FROM AUTHOR]

The results of the thermalized flux calculation that incorporate radiative capture reactions in the presence and absence of polyethylene blocks that form an enclosure for a deuteron-deuteron (D-D) neutron generator are presented. This method can be used to measure the moderated neutron flux component in a mixture of moderated and primary neutron spectra. Using 20-cm-thick polyethylene blocks to surround a D-D neutron generator, the moderation of primary neutrons was investigated using nine indium foils. In this paper, the relationship between the moderated neutron flux and the radiative capture rates in the presence and absence of polyethylene blocks is derived. This is compared to a MCNP simulation and a calculation of modulated flux that ignore the primary neutron components. [ABSTRACT FROM AUTHOR]

Selective laser sintering (SLS) is gaining increasing importance in polymer additive manufacturing. It has many unique advantages compared with extrusion or photopolymerization based technologies. However, one of the main challenges for SLS is the limited types of compatible polymer microparticles. This study develops a versatile material platform for the scalable synthesis of polyethylene (PE) and its composite microparticles for SLS 3D printing. The incorporation of metal oxide nanoparticles inside PE microparticles by in situ sol‐gel chemistry as well as blending with carbon black for enhanced laser absorption is found to have significant impacts on the printability and physical properties of printed structures. Importantly, this study also demonstrates that post‐printing processing can substantially enhance the mechanical properties and introduce new functionalities to 3D PE structures. Thermal annealing improves the mechanical strength and modulus by more than ten times. Electrochemical deposition of copper on the 3D PE composite structures significantly enhances the electrical conductivity and mechanical properties, which can be utilized to fabricate 3D hierarchical metallic structures with broad applications. [ABSTRACT FROM AUTHOR]

Polyethylene (PE) is the most commonly used plastic type in the world, contributing significantly to the plastic waste crisis. Microbial degradation of PE in natural environments is unlikely due to its inert saturated carbon‐carbon backbones, which are difficult to break down by enzymes, challenging the development of a biocatalytic recycling method for PE waste. Here, we demonstrated the depolymerization of low‐molecular‐weight (LMW) PE using an enzyme cascade that included a catalase‐peroxidase, an alcohol dehydrogenase, a Baeyer Villiger monooxygenase, and a lipase after the polymer was chemically pretreated with m‐chloroperoxybenzoic acid (mCPBA) and ultrasonication. In a preparative experiment with gram‐scale pretreated polymers, GC‐MS and weight loss determinations confirmed ~27 % polymer conversion including the formation of medium‐size functionalized molecules such as ω‐hydroxycarboxylic acids and α,ω‐carboxylic acids. Additional analyses of LMWPE‐nanoparticles using AFM showed that enzymatic depolymerization reduced the sizes of these mCPBA‐ and enzyme‐treated LMWPE‐nanoparticles. This multi‐enzyme catalytic concept with distinct chemical steps represents a unique starting point for future development of bio‐based recycling methods for polyolefin waste. [ABSTRACT FROM AUTHOR]

Developing plastics that fill the need of polyolefins yet are more easily recyclable is a critical need to address the plastic waste crisis. However, most efforts in this vein have focused on high‐density polyethylene (PE), while many different types of PE exist. To create broadly sustainable PE with modular properties, we present the synthesis, characterization, and demonstration of materials applications for chemically recyclable PE‐like multiblock polymers prepared from distinct hard and soft blocks using ruthenium‐catalyzed dehydrogenative polymerization. By altering the branching pattern within the soft blocks, a series of PE‐like multiblock polymers were synthesized with tunable glass transition temperatures (Tg) while maintaining consistent high melting temperatures (Tm). A clear U‐shape trend between Tg and mechanical properties was found, showcasing their potential as sustainable materials with tailored properties spanning commercial linear low‐density polyethylene (LLDPE) and low‐density polyethylene (LDPE). These materials offer adjustable adhesive strength to metal and demonstrate chemical recyclability and selective depolymerization in mixed plastic streams, promoting circularity and separation. [ABSTRACT FROM AUTHOR]

Microwave‐assisted pyrolysis of PE to hydrogen and carbon material has great potential to solve the problem of waste PE induced white pollution and provide a promising way to produce hydrogen energy. To increase the hydrogen yield, a new microwave‐assisted pyrolysis procedure should be developed. In the present study, a facile double‐layer microwave‐assisted pyrolysis (DLMP) method is developed to pyrolyze PE. Within this method, PE can be converted to hydrogen, multiwalled carbon nanotubes with extremely high efficiency compared with the traditional methods. A high hydrogen yield of 66.4 mmol g−1PE is achieved, which is ≈93% of the upper limit of the theoretical hydrogen yield generated from the PE pyrolysis process. The mechanism of high hydrogen yield during the microwave‐assisted pyrolysis of PE using the DLMP method is also clarified in detail. The DLMP method paved the potential way for recycling plastic waste into high‐value‐added products. [ABSTRACT FROM AUTHOR]

Micro/nanoplastics (MNPs), which are widely spread in the environment, have gained attention because of their ability to enter the human body mainly through ingestion, inhalation, and skin contact, thus representing a serious health threat. Several studies have reported the presence of MNPs in lung tissue and the potential role of MNP inhalation in triggering lung fibrosis and tumorigenesis. However, there is a paucity of knowledge regarding the cellular response to MNPs composed of polyethylene (PE), one of the most common plastic pollutants in the biosphere. In this study, we investigated the effects of low/high concentrations of PE MNPs on respiratory epithelial cell viability and migration/invasion abilities, using MTT, scratch, and transwell assays. Morphological and molecular changes were assessed via immunofluorescence, Western blot, and qRT-PCR. We demonstrated that acute exposure to PE MNPs does not induce cellular toxicity. Instead, cells displayed visible morphological changes also involving actin cytoskeleton reorganization. Our data underlined the role of epithelial–mesenchymal transition (EMT) in triggering this process. Moreover, a remarkable increase in migration potential was noticed, in absence of a significant alteration of the cell's invasive capacity. The present study highlights the potential impact of PE MNPs inhalation on the human respiratory epithelium, suggesting a possible role in carcinogenesis. [ABSTRACT FROM AUTHOR]

[Display omitted] • Valorizing XLPE plastic residue through catalytic flash pyrolysis. • Precise profiling: Py–GC/MS setup dissects volatile reaction products at 500 °C. • Kaolin catalyst: proven as a low-cost natural catalyst for flash pyrolysis. • Catalyst impact: kaolin shifts hydrocarbon concentration favorably. • Plastic waste yields gasoline-range hydrocarbons from catalytic flash pyrolysis. This investigation's novelty and objective reside in exploring catalytic flash pyrolysis of cross-linked polyethylene (XLPE) plastic residue in the presence of kaolin, with the perspective of achieving sustainable production of gasoline-range hydrocarbons. Through proximate analysis, thermogravimetric analysis, and heating value determination, this study also assessed the energy-related characteristics of cross-linked polyethylene plastic residue, revealing its potential as an energy source (44.58 MJ kg−1) and suitable raw material for pyrolysis due to its low ash content and high volatile matter content. To understand the performance as a low-cost catalyst in the flash pyrolysis of cross-linked polyethylene plastic residue, natural kaolin was subjected to characterization through thermogravimetric analysis, X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR), and X-ray fluorescence (XRF). Cross-linked polyethylene plastic residue was subjected to thermal and catalytic pyrolysis in an analytical microreactor coupled to gas chromatography-mass spectrometry (Py–GC/MS system), operating at 500 °C, to characterize the distribution and composition of volatile reaction products. The application of kaolin as a catalyst resulted in a decline of the relative concentration of hydrocarbons in the diesel range (C 8 -C 24) from approximately 87 % to 28 %, and a reduction in lubricating oils (C 14 -C 50) from about 70 % to 13 %, while concomitantly increasing the relative concentration of lighter hydrocarbons in the gasoline range (C 8 -C 12) from around 28 % to 87 %. Therefore, catalytic flash pyrolysis offers the potential for converting this plastic waste into a new and abundant chemical source of gasoline-range hydrocarbons. This process can be deemed viable and sustainable for managing and valorizing cross-linked polyethylene plastic residue. [ABSTRACT FROM AUTHOR]

The present Bayesian network meta-analysis compared different types of polyethylene liners in total hip arthroplasty (THA) in terms of wear penetration (mm/year) and rate of revision. The type of liners compared were the crosslinked ultra-high molecular weight polyethylene (CPE/UHMWPE), Vitamin E infused highly cross-linked polyethylene (HXLPE-VEPE), modified cross-linked polyethylene (MXLPE), highly cross-linked polyethylene (HXLPE), Cross-linked polyethylene (XLPE). This study was conducted according to the PRISMA extension statement for reporting systematic reviews incorporating network meta-analyses of healthcare interventions. In June 2024, PubMed, Scopus, Embase, Google Scholar, and Cochrane databases were accessed. A time constraint was set from January 2000. All investigations which compared two or more types of polyethylene liners for THA were accessed. Only studies that clearly stated the nature of the liner were included. Data from 60 studies (37,352 THAs) were collected. 56% of patients were women. The mean age of patients was 60.0 ± 6.6 years, the mean BMI was 27.5 ± 2.0 kg/m2. The mean length of follow-up was 81.6 ± 44.4 months. Comparability was found at baseline between groups. XLPE and HXLPE liners in THA are associated with the lowest wear penetration (mm/year) and the lowest revision rate at approximately 7 years of follow-up. [ABSTRACT FROM AUTHOR]

Reduced graphene oxide (rGO) was prepared from waste plastic using the two steps pyrolysis method and subsequently functionalized with ethylene diamine (EDA) to develop amino‐functionalized rGO (EDA‐rGO). To make the thermal and mechanical properties more proficient, EDA‐rGO was further incorporated as a nanofiller into a low‐density polyethylene (LDPE) matrix using the melt mixing method followed by hot‐pressing. A variety of analytical methods, such as FT‐IR, XRD, XPS, DSC, TGA, DMA, Raman spectroscopy, and HRTEM, were used to characterize the elements and morphology of rGO and EDA‐rGO. The results showed that the addition of 5 wt% EDA‐rGO to LDPE polymers significantly improved the mechanical and thermal properties, such as storage modulus by 62%, loss modulus by 67%, young's modulus by 123%, tensile strength by 79.83%, respectively. The thermal decomposition temperatures of 5%, 10% and 50% were increased by 14.01, 9.34, and 4.8°C, respectively. This study provides a feasible and ecologically sustainable way of repurposing plastic waste concurrently enhancing the properties of polymer composites. Highlights: Synthesis & functionalization of rGO from waste plastic using EDA.EDA‐rGO used as a nanofiller to fabricate LDPE polymer nanocomposites.EDA‐rGO enhanced the thermal stability of LDPE nanocomposites.The tensile strength & modulus of the LDPE composites are greatly improved.The storage, loss modulus, Tm and Tc enhanced by 62%, 67%, 4.4°C & 2.6°C. [ABSTRACT FROM AUTHOR]