Inhalable Textile Microplastic Fibers Impair Airway Epithelial Differentiation.

Rationale: Microplastics are a pressing global concern, and inhalation of microplastic fibers has been associated with interstitial and bronchial inflammation in flock workers. However, how microplastic fibers affect the lungs is unknown. Objectives: Our aim was to assess the effects of 12 × 31 µm nylon 6,6 (nylon) and 15 × 52 µm polyethylene terephthalate (polyester) textile microplastic fibers on lung epithelial growth and differentiation. Methods: We used human and murine alveolar and airway-type organoids as well as air-liquid interface cultures derived from primary lung epithelial progenitor cells and incubated these with either nylon or polyester fibers or nylon leachate. In addition, mice received one dose of nylon fibers or nylon leachate, and, 7 days later, organoid-forming capacity of isolated epithelial cells was investigated. Measurements and Main Results: We observed that nylon microfibers, more than polyester, inhibited developing airway organoids and not established ones. This effect was mediated by components leaching from nylon. Epithelial cells isolated from mice exposed to nylon fibers or leachate also formed fewer airway organoids, suggesting long-lasting effects of nylon components on epithelial cells. Part of these effects was recapitulated in human air-liquid interface cultures. Transcriptomic analysis revealed upregulation of Hoxa5 after exposure to nylon fibers. Inhibiting Hoxa5 during nylon exposure restored airway organoid formation, confirming Hoxa5's pivotal role in the effects of nylon. Conclusions: These results suggest that components leaching from nylon 6,6 may especially harm developing airways and/or airways undergoing repair, and we strongly encourage characterization in more detail of both the hazard of and the exposure to microplastic fibers.

Biochemical and structural characterization of an aromatic ring-hydroxylating dioxygenase for terephthalic acid catabolism.

SignificanceMore than 400 million tons of plastic waste is produced each year, the overwhelming majority of which ends up in landfills. Bioconversion strategies aimed at plastics have emerged as important components of enabling a circular economy for synthetic plastics, especially those that exhibit chemically similar linkages to those found in nature, such as polyesters. The enzyme system described in this work is essential for mineralization of the xenobiotic components of poly(ethylene terephthalate) (PET) in the biosphere. Our description of its structure and substrate preferences lays the groundwork for in vivo or ex vivo engineering of this system for PET upcycling.

PEGylated liposomes for diagnosis of polyethylene glycol allergy.

BACKGROUND: Polyethylene glycol (PEG) is a nonprotein polymer that is present in its native (unbound) form as an excipient in a range of products. It is increasingly being utilized clinically in the form of PEGylated liposomal medications and vaccines. PEG is the cause of anaphylaxis in a small percentage of drug reactions; however, diagnosis of PEG allergy is complicated by the variable and poor diagnostic performance of current skin testing protocols. OBJECTIVE: We assessed the diagnostic performance of PEGylated lipid medications as an alternative to currently described tests that use medications containing PEG excipients. METHODS: Nine patients with a strong history of PEG allergy were evaluated by skin testing with a panel of PEG-containing medications and with a PEGylated lipid nanoparticle vaccine (BNT162b2). Reactivity of basophils to unbound and liposomal PEG was assessed ex vivo, and specificity of basophil responses to PEGylated liposomes was investigated with a competitive inhibition assay. More detailed information is provided in this article's Methods section in the Online Repository available at www.jacionline.org. RESULTS: Despite compelling histories of anaphylaxis to PEG-containing medications, only 2 (22%) of 9 patients were skin test positive for purified PEG or their index reaction-indicated PEG-containing compound. Conversely, all 9 patients were skin test positive or basophil activation test positive to PEGylated liposomal BNT162b2 vaccine. Concordantly, PEGylated liposomal drugs (BNT162b2 vaccine and PEGylated liposomal doxorubicin), but not purified PEG2000, consistently induced basophil activation ex vivo in patients with PEG allergy but not in nonallergic controls. Basophil reactivity to PEGylated nanoparticles competitively inhibited by preincubation of basophils with native PEG2000. CONCLUSION: Presentation of PEG on the surface of a lipid nanoparticle increases its in vivo and ex vivo allergenicity, and improves diagnosis of PEG allergy.

Accelerated Solar-Driven Polyolefin Degradation via Self-Activated Hydroxy-Rich ZnIn2S4.

Degradation of polyolefin (PE) plastic by a traditional chemical method requires a high pressure and a high temperature but generates complex products. Here, sulfur vacancy-rich ZnIn2S4 and hydroxy-rich ZnIn2S4 were rationally fabricated to realize photocatalytic degradation of PE in an aqueous solution under mild conditions. The results reveal that the optimized photocatalyst could degrade PE into CO2 and CO, and PE had a weight loss of 84.5% after reaction for 60 h. Systematic experiments confirm that the synergetic effect of hydroxyl groups and S vacancies contributes to improve the photocatalytic degradation properties of plastic wastes. In-depth investigation illustrates that the active radicals attack (h+ and •OH) weak spots (C-H and C-C bonds) of the PE chain to form CO2, which is further selectively photoreduced to CO. Multimodule synergistic tandem catalysis can further improve the utilization value of plastic wastes; for example, product CO2/CO in the plastic degradation process can be converted in situ into HCOOH by coupling with electrocatalytic technology.

American Gastroenterological Association-American College of Gastroenterology Clinical Practice Guideline: Pharmacological Management of Chronic Idiopathic Constipation.

INTRODUCTION: Chronic idiopathic constipation (CIC) is a common disorder associated with significant impairment in quality of life. This clinical practice guideline, jointly developed by the American Gastroenterological Association and the American College of Gastroenterology, aims to inform clinicians and patients by providing evidence-based practice recommendations for the pharmacological treatment of CIC in adults. METHODS: The American Gastroenterological Association and the American College of Gastroenterology formed a multidisciplinary guideline panel that conducted systematic reviews of the following agents: fiber, osmotic laxatives (polyethylene glycol, magnesium oxide, lactulose), stimulant laxatives (bisacodyl, sodium picosulfate, senna), secretagogues (lubiprostone, linaclotide, plecanatide), and serotonin type 4 agonist (prucalopride). The panel prioritized clinical questions and outcomes and used the Grading of Recommendations Assessment, Development, and Evaluation framework to assess the certainty of evidence for each intervention. The Evidence to Decision framework was used to develop clinical recommendations based on the balance between the desirable and undesirable effects, patient values, costs, and health equity considerations. RESULTS: The panel agreed on 10 recommendations for the pharmacological management of CIC in adults. Based on available evidence, the panel made strong recommendations for the use of polyethylene glycol, sodium picosulfate, linaclotide, plecanatide, and prucalopride for CIC in adults. Conditional recommendations were made for the use of fiber, lactulose, senna, magnesium oxide, and lubiprostone. DISCUSSION: This document provides a comprehensive outline of the various over-the-counter and prescription pharmacological agents available for the treatment of CIC. The guidelines are meant to provide a framework for approaching the management of CIC; clinical providers should engage in shared decision making based on patient preferences as well as medication cost and availability. Limitations and gaps in the evidence are highlighted to help guide future research opportunities and enhance the care of patients with chronic constipation.

Microplastics increase cadmium absorption and impair nutrient uptake and growth in red amaranth (Amaranthus tricolor L.) in the presence of cadmium and biochar.

Microplastic (MP) pollution in terrestrial ecosystems is gaining attention, but there is limited research on its effects on leafy vegetables when combined with heavy metals. This study examines the impact of three MP types-polyethylene (PE), polyethylene terephthalate (PET), and polystyrene (PS)-at concentrations of 0.02, 0.05, and 0.1% w/w, along with cadmium (Cd) and biochar (B), on germination, growth, nutrient absorption, and heavy metal uptake in red amaranth (Amaranthus tricolor L.). We found that different MP types and concentrations did not negatively affect germination parameters like germination rate, relative germination rate, germination vigor, relative germination vigor, and germination speed. However, they increased phytotoxicity and decreased stress tolerance compared to an untreated control (CK1). The presence of MPs, particularly the PS type, reduced phosphorus and potassium uptake while enhancing Cd uptake. For example, treatments PS0.02CdB, PS0.05CdB, and PS0.1CdB increased Cd content in A. tricolor seedlings by 158%, 126%, and 44%, respectively, compared to the treatment CdB (CK2). Additionally, MP contamination led to reduced plant height, leaf dry matter content, and fresh and dry weights, indicating adverse effects on plant growth. Moreover, the presence of MPs increased bioconcentration factors and translocation factors for Cd, suggesting that MPs might act as carriers for heavy metal absorption in plants. On the positive side, the addition of biochar improved several root parameters, including root length, volume, surface area, and the number of root tips in the presence of MPs, indicating potential benefits for plant growth. Our study shows that the combination of MPs and Cd reduces plant growth and increases the risk of heavy metal contamination in food crops. Further research is needed to understand how different MP types and concentrations affect various plant species, which will aid in developing targeted mitigation strategies and in exploring the mechanisms through which MPs impact plant growth and heavy metal uptake. Finally, investigating the potential of biochar application in conjunction with other amendments in mitigating these effects could be key to addressing MP and heavy metal contamination in agricultural systems.

PEG treatment is unsuitable to study root related traits as it alters root anatomy in barley (Hordeum vulgare L.).

BACKGROUND: The frequency and severity of abiotic stress events, especially drought, are increasing due to climate change. The plant root is the most important organ for water uptake and the first to be affected by water limitation. It is therefore becoming increasingly important to include root traits in studies on drought stress tolerance. However, phenotyping under field conditions remains a challenging task. In this study, plants were grown in a hydroponic system with polyethylene glycol as an osmotic stressor and in sand pots to examine the root system of eleven spring barley genotypes. The root anatomy of two genotypes with different response to drought was investigated microscopically. RESULTS: Root diameter increased significantly (p < 0.05) under polyethylene glycol treatment by 54% but decreased significantly (p < 0.05) by 12% under drought stress in sand pots. Polyethylene glycol treatment increased root tip diameter (51%) and reduced diameter of the elongation zone (14%) compared to the control. Under drought stress, shoot mass of plants grown in sand pots showed a higher correlation (r = 0.30) with the shoot mass under field condition than polyethylene glycol treated plants (r = -0.22). CONCLUSION: These results indicate that barley roots take up polyethylene glycol by the root tip and polyethylene glycol prevents further water uptake. Polyethylene glycol-triggered osmotic stress is therefore unsuitable for investigating root morphology traits in barley. Root architecture of roots grown in sand pots is more comparable to roots grown under field conditions.

GO-PEG Represses the Progression of Liver Inflammation via Regulating the M1/M2 Polarization of Kupffer Cells.

As a highly promising nanomaterial, exploring the impact of the liver, a vital organ, stands out as a crucial focus in the examination of its biological effects. Kupffer cells (KCs) are one of the first immune cells to contact with exotic-substances in liver. Therefore, this study investigates the immunomodulatory effects and mechanisms of polyethylene glycol-modified graphene oxide (GO-PEG) on KCs. Initial RNA-seq and KEGG pathway analyses reveal the inhibition of the TOLL-like receptor, TNF-α and NOD-like receptor pathways in continually stimulated KCs exposed to GO-PEG. Subsequent biological experiments validate that a 48-hour exposure to GO-PEG alleviates LPS-induced KCs immune activation, characterized by a shift in polarization from M1 to M2. The underlying mechanism involves the absorption of double-stranded RNA/single-stranded RNA, inhibiting the activation of TLR3 and TLR7 in KCs. Employing a Kupffer/AML12 cell co-culture model and animal studies, it is observed that GO-PEG indirectly inhibit oxidative stress, mitochondrial dysfunction, and apoptosis in AML12 cells, partially mitigating systemic inflammation and preserving liver tissue/function. This effect is attributed to the paracrine interaction between KCs and hepatocytes. These findings suggest a meaningful and effective strategy for treating liver inflammation, particularly when combined with anti-inflammatory drugs.

Reversible Sensing Technologies Using Upcycled TPEE: Crafting pH and Light Responsive Materials towards Sustainable Monitoring.

Multiresponsive materials with reversible and durable characteristics are indispensable because of their promising applications in environmental change detections. To fabricate multiresponsive materials in mass production, however, complex reactions and impractical situations are often involved. Herein, a dual responsive (light and pH) spiropyran-based smart sensor fabricated by a simple layer-by-layer (LbL) assembly process from upcycled thermoplastic polyester elastomer (TPEE) materials derived from recycled polyethylene terephthalate (r-PET) is proposed. Positively charged chitosan solutions and negatively charged merocyanine-COOH (MC-COOH) solutions are employed in the LbL assembly technique, forming the chitosan-spiropyran deposited TPEE (TPEE-CH-SP) film. Upon UV irradiation, the spiropyran-COOH (SP-COOH) molecules on the TPEE-CH-SP film undergo the ring-opening isomerization, along with an apparent color change from colorless to purple, to transform into the MC-COOH molecules. By further exposing the TPEE-CH-MC film to hydrogen chloride (HCl) and nitric acid (HNO3) vapors, the MC-COOH molecules can be transformed into protonated merocyanine-COOH (MCH-COOH) with the simultaneous color change from purple to yellow.

A Super-Ionic Solid-State Block Copolymer Electrolyte.

Polymer solid-state electrolytes offer great promise for battery materials with high energy density, mechanical stability, and improved safety. However, their low ion conductivities have so far limited their potential applications. Here, it is shown for poly(ethylene oxide) block copolymers that the super-stoichiometric addition of lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) as lithium salt leads to the formation of a crystalline PEO block copolymer phase with exceptionally high ion conductivities and low activation energies. The addition of LiTFSI further induces block copolymer phase transitions into bi-continuous Fddd and gyroid network morphologies, providing continuous 3D conduction pathways. Both effects lead to solid-state block copolymer electrolyte membranes with ion conductivities of up to 1·10-1 S cm-1 at 90 °C, decreasing only moderately to 4·10-2 S cm-1 at room temperature, and to >1·10-3 S cm-1 at -20 °C, corresponding to activation energies as low as 0.19 eV. The co-crystallization of PEO and LiTFSI with ether and carbonate solvents is observed to play a key role to realize a super-ionic conduction mechanism. The discovery of PEO super-ionic conductivity at high lithium concentrations opens a new pathway for fabrication of solid polymer electrolyte membranes with sufficiently high ion conductivities over a broad temperature range with widespread applications in electrical devices.

PEO-Based Solid Composite Polymer Electrolyte for High Capacity Retention All-Solid-State Lithium Metal Battery.

The limited ionic conductivity at room temperature and the constrained electrochemical window of poly(ethylene oxide) (PEO) pose significant obstacles that hinder its broader utilization in high-energy-density lithium metal batteries. The garnet-type material Li6.4 La3 Zr1.4 Ta0.6 O12 (LLZTO) is recognized as a highly promising active filler for enhancing the performance of PEO-based solid polymer electrolytes (SPEs). However, its performance is still limited by its high interfacial resistance. In this study, a novel hybrid filler-designed SPE is employed to achieve excellent electrochemical performance for both the lithium metal anode and the LiFePO4 cathode. The solid composite membrane containing hybrid fillers achieves a maximum ionic conductivity of 1.9 × 10-4 S cm-1 and a Li+ transference number of 0.67 at 40 °C, respectively. Additionally, the Li/Li symmetric cells demonstrate a smooth and stable process for 2000 h at a current density of 0.1 mA cm-2 . Furthermore, the LiFePO4 /Li battery delivers a high-rate capacity of 159.2 mAh g-1 at 1 C, along with a capacity retention of 95.2% after 400 cycles. These results validate that employing a composite of both active and inactive fillers is an effective strategy for achieving superior performance in all-solid-state lithium metal batteries (ASSLMBs).

Ultrathin, Mechanically Durable, and Scalable Polymer-in-Salt Solid Electrolyte for High-Rate Lithium Metal Batteries.

Polymer-in-salt solid-state electrolytes (PIS SSEs) are emerging for high room-temperature ionic conductivity and facile handling, but suffer from poor mechanical durability and large thickness. Here, Al2O3-coated PE (PE/AO) separators are proposed as robust and large-scale substrates to trim the thickness of PIS SSEs without compromising mechanical durability. Various characterizations unravel that introducing Al2O3 coating on PE separators efficiently improves the wettability, thermal stability, and Li-dendrite resistance of PIS SSEs. The resulting PE/AO@PIS demonstrates ultra-small thickness (25 µm), exceptional mechanical durability (55.1 MPa), high decomposition temperature (330 °C), and favorable ionic conductivity (0.12 mS cm-1 at 25 °C). Consequently, the symmetrical Li cells remain stable at 0.1 mA cm-2 for 3000 h, without Li dendrite formation. Besides, the LiFePO4|Li full cells showcase excellent rate capability (131.0 mAh g-1 at 10C) and cyclability (93.6% capacity retention at 2C after 400 cycles), and high-mass-loading performance (7.5 mg cm-2). Moreover, the PE/AO@PIS can also pair with nickel-rich layered oxides (NCM811 and NCM9055), showing a remarkable specific capacity of 165.3 and 175.4 mAh g-1 at 0.2C after 100 cycles, respectively. This work presents an effective large-scale preparation approach for mechanically durable and ultrathin PIS SSEs, driving their practical applications for next-generation solid-state Li-metal batteries.

An Assay for Immunogenic Detection of Anti-PEG Antibody.

With the increasing use of polyethylene glycol (PEG) based proteins and drug delivery systems, anti-PEG antibodies have commonly been detected among the population, causing the accelerated blood clearance and hypersensitivity reactions, poses potential risks to the clinical efficacy and safety of PEGylated drugs. Therefore, vigilant monitoring of anti-PEG antibodies is crucial for both research and clinical guidance regarding PEGylated drugs. The enzyme-linked immunosorbent assay (ELISA) is a common method for detecting anti-PEG antibodies. However, diverse coating methods, blocking solutions and washing solutions have been employed across different studies, and unsuitable use of Tween 20 as the surfactant even caused biased results. In this study, we established the optimal substrate coating conditions, and investigated the influence of various surfactants and blocking solutions on the detection accuracy. The findings revealed that incorporating 1 % bovine serum albumin into the serum dilution in the absence of surfactants will result the credible outcomes of anti-PEG antibody detection.

Metagenome-derived SusD-homologs affiliated with Bacteroidota bind to synthetic polymers.

Starch utilization system (Sus)D-homologs are well known for their carbohydrate-binding capabilities and are part of the sus operon in microorganisms affiliated with the phylum Bacteroidota. Until now, SusD-like proteins have been characterized regarding their affinity toward natural polymers. In this study, three metagenomic SusD homologs (designated SusD1, SusD38489, and SusD70111) were identified and tested with respect to binding to natural and non-natural polymers. SusD1 and SusD38489 are cellulose-binding modules, while SusD70111 preferentially binds chitin. Employing translational fusion proteins with superfolder GFP (sfGFP), pull-down assays, and surface plasmon resonance (SPR) has provided evidence for binding to polyethylene terephthalate (PET) and other synthetic polymers. Structural analysis suggested that a Trp triad might be involved in protein adsorption. Mutation of these residues to Ala resulted in an impaired adsorption to microcrystalline cellulose (MC), but not so to PET and other synthetic polymers. We believe that the characterized SusDs, alongside the methods and considerations presented in this work, will aid further research regarding bioremediation of plastics. IMPORTANCE: SusD1 and SusD38489 can be considered for further applications regarding their putative adsorption toward fossil-fuel based polymers. This is the first time that SusD homologs from the polysaccharide utilization loci (PUL), largely described for the phylum Bacteroidota, are characterized as synthetic polymer-binding proteins.

Biodegradation of low-density polyethylene by mixed fungi composed of Alternaria sp. and Trametes sp. isolated from landfill sites.

With the development of industry and modern manufacturing, nondegradable low-density polyethylene (LDPE) has been widely used, posing a rising environmental hazard to natural ecosystems and public health. In this study, we isolated a series of LDPE-degrading fungi from landfill sites and carried out LDPE degradation experiments by combining highly efficient degrading fungi in pairs. The results showed that the mixed microorganisms composed of Alternaria sp. CPEF-1 and Trametes sp. PE2F-4 (H-3 group) had a greater degradation effect on heat-treated LDPE (T-LDPE). After 30 days of inoculation with combination strain H-3, the weight loss rate of the T-LDPE film was approximately 154% higher than that of the untreated LDPE (U-LDPE) film, and the weight loss rate reached 0.66 ± 0.06%. Environmental scanning electron microscopy (ESEM) and Fourier transform infrared spectroscopy (FTIR) were used to further investigate the biodegradation impacts of T-LDPE, including the changes on the surface and depolymerization of the LDPE films during the fungal degradation process. Our findings revealed that the combined fungal treatment is more effective at degrading T-LDPE than the single strain treatment, and it is expected that properly altering the composition of the microbial community can help lessen the detrimental impact of plastics on the environment.

Towards understanding the crystallization of photosystem II: influence of poly(ethylene glycol) of various molecular sizes on the micelle formation of alkyl maltosides.

The influence of poly(ethylene glycol) (PEG) polymers H-(O-CH2-CH2)p-OH with different average molecular sizes p on the micelle formation of n-alkyl-ß-D-maltoside detergents with the number of carbon atoms in the alkyl chain ranging from 10 to 12 is investigated with the aim to learn more about the detergent behavior under conditions suitable for the crystallization of the photosynthetic pigment-protein complex photosystem II. PEG is shown to increase the critical micelle concentration (CMC) of all three detergents in the crystallization buffer in a way that the free energy of micelle formation increases linearly with the concentration of oxyethylene units (O-CH2-CH2) irrespective of the actual molecular weight of the polymer. The CMC shift is modeled by assuming for simplicity that it is dominated by the interaction between PEG and detergent monomers and is interpreted in terms of an increase of the transfer free energy of a methylene group of the alkyl chain by 0.2 kJ mol-1 per 1 mol L-1 increase of the concentration of oxyethylene units at 298 K. Implications of this effect for the solubilization and crystallization of protein-detergent complexes as well as detergent extraction from crystals are discussed.

Elucidating allergic reaction mechanisms in response to SARS-CoV-2 mRNA vaccination in adults.

BACKGROUND: During the COVID-19 pandemic, novel nanoparticle-based mRNA vaccines were developed. A small number of individuals developed allergic reactions to these vaccines although the mechanisms remain undefined. METHODS: To understand COVID-19 vaccine-mediated allergic reactions, we enrolled 19 participants who developed allergic events within 2 h of vaccination and 13 controls, nonreactors. Using standard hemolysis assays, we demonstrated that sera from allergic participants induced stronger complement activation compared to nonallergic subjects following ex vivo vaccine exposure. RESULTS: Vaccine-mediated complement activation correlated with anti-polyethelyne glycol (PEG) IgG (but not IgM) levels while anti-PEG IgE was undetectable in all subjects. Depletion of total IgG suppressed complement activation in select individuals. To investigate the effects of vaccine excipients on basophil function, we employed a validated indirect basophil activation test that stratified the allergic populations into high and low responders. Complement C3a and C5a receptor blockade in this system suppressed basophil response, providing strong evidence for complement involvement in vaccine-mediated basophil activation. Single-cell multiome analysis revealed differential expression of genes encoding the cytokine response and Toll-like receptor (TLR) pathways within the monocyte compartment. Differential chromatin accessibility for IL-13 and IL-1B genes was found in allergic and nonallergic participants, suggesting that in vivo, epigenetic modulation of mononuclear phagocyte immunophenotypes determines their subsequent functional responsiveness, contributing to the overall physiologic manifestation of vaccine reactions. CONCLUSION: These findings provide insights into the mechanisms underlying allergic reactions to COVID-19 mRNA vaccines, which may be used for future vaccine strategies in individuals with prior history of allergies or reactions and reduce vaccine hesitancy.

Continuous Synthesis of a Macrocyclic Sulfite of Polyethylene Glycol by Cascaded Continuous Stirred Tank Reactors (CSTRs).

Many macrocyclic compounds are attractive drug-like molecules or intermediates due to their special properties. However, the bulk synthesis of such compounds are hindered by the necessity of using diluted solutions, in order to prevent intermolecular reactions that yields oligomer impurities, thereby resulting in a low production efficiency. Such challenge can be adequately addressed by using continuous reactors, allowing improved efficiency with smaller space footprints. In this work, we proposed a novel continuous process for the synthesis of a macrocyclic sulfite of tetraethylene glycol (PEG4-MCSi), which is a precursor to a very useful building block, PEG4-macrocyclic sulfate (PEG4-MCS). The basic reaction parameters, including stoichiometry and temperature, were first confirmed with small batch reactions, and the effectiveness of coiled reactors and continuous stirred tank reactors (CSTRs) were compared. Cascaded CSTRs were proven to be suitable, and the reaction parameters were subject to further optimization to give a robust continuous process. The process was then tested with 4 parallel runs for up to 64 h. Finally, the merits and demerits of batch and continuous reactions were also compared, demonstrating the suitability of latter in the bulk production of macrocyclic PEG-MCSi compounds.

Barbier Polymerization-Induced Emission towards Fully Substituted Polyethylene Analogues with Non-Traditional Intrinsic Luminescence.

The properties of polyethylene are highly dependent on the variety and quantity of substitutions. Generally, polyethylene can only be fully substituted with fluorine atoms, mainly e. g., polytetrafluoroethylene and nafion, because atomic radius of fluorine atom is small enough. The preparation of fully substituted polyethylene analogues (FSPEA) and their non-traditional intrinsic luminescence (NTIL) are attractive, especially for substitutions with relatively larger atomic radii than a fluorine atom. Here, Barbier polymerization-induced emission (PIE) is demonstrated as a universal method for the molecular design of NTIL type FSPEAs with intriguing aggregation-induced emission (AIE) behaviors. Through Barbier polymerization of diphenyldichloromethane and different peroxyesters in the presence of Mg in one pot, a series of FSPEAs, including polytriphenylethanol (PTPE), polydiphenylfurylethanol (PDPFE), polydiphenylthiophenylethanol (PDPTE) and polydiphenylnaphthylethanol (PDPNE) have been successfully prepared. Further potential applications for explosive detection, artificial light-harvesting system and white phosphor-converted light-emitting diode are investigated. Therefore, this work opens up a new approach for the molecular design of FSPEA with non-conjugated luminescence, which may cause inspirations to different research fields like polyolefin and luminescent materials.

Improving Environmental Stress Cracking Resistance of High-Density Polyethylene Grades by Comonomer Addition and Nanocomposite Approach.

The aim of this paper is to determine the effect of polymer density, correlated to the comonomer content, and nanosilica addition on the mechanical and Environmental Stress Cracking Resistance (ESCR) characteristics of high-density polyethylene (HDPE). In this regard, five HDPE samples with similar Melt Flow Index (MFI) and molar mass but various densities were acquired from a petrochemical plant. Two polymerization reactors work in series and differ only in the amount of 1-buene comonomer fed to the second reactor. To ascertain the microstructure of the studied samples, GPC and SSA (successive self-nucleation and annealing) analyses were accomplished. All samples resulted having similar characteristics but slightly various SCB/1000 C=7.26-9.74 (SCB=Short Chain Branching). Consequently, meanwhile studied HDPEs reveal similar notched impact and stress at yield values, the tensile modulus, stress-at-break, and elongation-at-break tend to demonstrate different results with the SCB content. More significantly, ESCR characteristic varied considerably with SCB/1000 C extent, so that higher amount of SCB acknowledged advanced ESCR. Notably, blending HDPE sample containing higher amount of SCB/1000 C, with 3 wt.% of chemically modified nanosilica enhanced ESCR characteristic by 40 %. DFT (Density Functional Theory) calculations unveiled the role of the comonomer, quantitatively by binding energies and qualitatively by Non Covalent Interaction (NCI) plots.