Добірка наукової літератури з теми "Biphasic metal/polymer sublayer"

Solid-state batteries based on nonflammable inorganic solid electrolytes provide a promising technical solution that can resolve the safety issues of current lithium-ion batteries. Biphasic solid electrolytes comprising Li7La3Zr2O12 (LLZO) garnet and polymer have been attracting significant interest for solid-state Li batteries because of their mechanical robustness and enhanced Li+ conductivity, compared to conventional polymer electrolytes. Furthermore, the hybridization allows for the fabrication of thin and large-area electrolyte membranes without the need for high-temperature sintering of LLZO. However, the non-uniform distribution of LLZO particles and polymer species in biphasic electrolytes may cause uneven Li+ conduction, which results in poor interfacial stability with electrodes during repeated charge–discharge cycling. In this study, we report a biphasic solid electrolyte with homogeneous Li+ transport pathway achieved by a metal–organic framework (MOF) layer. To regulate and homogenize the Li+ flux across the interface between the electrolyte and electrode, a free-standing, biphasic solid electrolyte membrane is integrated with the MOF nanoparticle layer. A mixture of plastic crystal (PC) and polymeric phase is infused into porous networks of the MOF-integrated electrolyte membrane, producing the percolating Li+ conduction pathways. The MOF-integrated electrolyte membrane is found to form the smooth and uniform interface with nanoporous channels in contact with the electrodes, effectively facilitating homogeneous Li+ transport. A solid-state battery with the MOF-integrated electrolyte membrane shows the enhanced rate-capability and cycling stability in comparison to the battery with the unmodified biphasic electrolyte. This study demonstrates that the proposed electrolyte design provides an effective approach to improving the interfacial stability of biphasic electrolytes with electrodes for long-cycling solid-state batteries. [1] H.-S. Shin, W. Jeong, M.-H. Ryu, S.W. Lee, K.-N. Jung, J.-W. Lee, Electrode-to-electrode monolithic integration for high-voltage bipolar solid-state batteries based on plastic-crystal polymer electrolyte, Chem. Eng. J, published online. [2] T. Jiang, P. He, G. Wang, Y. Shen, C.-W. Nan, L.-Z. Fan, Solvent-free synthesis of thin, flexible, nonflammable garnet-based composite solid electrolyte for all-solid-state lithium batteries, Adv. Energy Mater. 10 (2020) 1903376.

An investigation was conducted for the study of extraction of metal ions using aqueous biphasic systems. The extraction of iron, zinc and copper from aqueous sulphate media at different kinds of extractants SCN− , Cl- and I- , different values of pH of the feed solution, phase ratio, concentration of metals, concentration of extractant, concentration of polymer, and concentration of salt was investigated. Atomic absorption spectrophotometer was used to measure the concentration of iron, zinc and copper in the aqueous phase throughout the experiments. The results of the extraction experiments showed the use of SCN− as extractant, pH=2.5, phase ratio=1.5, concentration of metals 1g/l, concentration of extractant 0.06 %, concentration of polymer =50 %, and concentration of salt=20% gave the highest value of percent removed. Also increase of extractant concentration increases the percent removed. The results clarified that increasing the metal ions concentration in the aqueous phase causes to decease the percent removed. The addition of an inorganic salt (sodium sulphate) up to (20%) increased the dehydration of polymer chains and then increases the percent removed.

Using gas-phase deposition (Physical Vapor Deposition (PVD) and Metal Organic Chemical Vapor Deposition (MOCVD)) methods, modern implant samples (Ti alloy and CFR-PEEK polymer, 30% carbon fiber) were functionalized with film heterostructures consisting of an iridium or gold sublayer, on the surface of which an antibacterial component (silver) was deposited: Ag/Ir(Au)/Ti(CFR-PEEK). The biocidal effect of the heterostructures was investigated, the effect of the surface relief of the carrier and the metal sublayer on antibacterial activity was established, and the dynamics of silver dissolution was evaluated. It has been shown that the activity of Ag/Ir heterostructures was due to high Ag+ release rates, which led to rapid (2–4 h) inhibition of P. aeruginosa growth. In the case of Ag/Au type heterostructures, the inhibition of the growth of P. aeruginosa and S. aureus occurred more slowly (from 6 h), and the antibacterial activity appeared to be due to the contribution of two agents (Ag+ and Au+ ions). It was found, according to the in vitro cytotoxicity study, that heterostructures did not exhibit toxic effects (cell viability > 95–98%). An in vivo biocompatibility assessment based on the results of a morphohistological study showed that after implantation for a period of 30 days, the samples were characterized by the presence of a thin fibrous capsule without volume thickening and signs of inflammation.

The biphasic hybrid composite materials for immobilization and fixation of radionuclides of the Liquid Radioactive Waste (LRW) of the research water-water reactor KIR WWR-K have been studied. It was found that the hybrid compositions have a high synergistic effect regard to the sorption of radionuclides, especially 137Cs+ and 134Cs+ . The distribution coefficient of cesium radionuclides in the composite materials are 2 times higher in comparison with the those sorption activity in the mineral matrix. It has been established that the sorption of radionuclides by two-phase hybrid compositions is carried out by a combination of three mechanisms. Firstly, due to the electrostatic binding reaction between the functional groups of sorbents and metal ions stabilized by the system of coordination bonds with electron-donating nitrogen and oxygen atoms of the amino and carbonyl groups of the polymer matrix. Secondly, as a result of ion exchange between counterions of the mineral matrix and radionuclides ions in the environmental solution. Finally, due to the superequimolar absorption of radionuclides as a result of deformation of the crystal lattice of mineral fillers of the polymer matrix of bentonite and copper ferrocyanide, which increases their pore size. It has been shown that biphasic hybrid composite materials have an increased mechanical and radiation resistance while retaining elasticity even at high doses of electron irradiation, at which in despite on a noticeable decrease the value of deformation there is no significant decline in their compressive strength. The obtained information on the mechanism of binding of biphasic hybrid composite materials with various metal ions makes it possible to synthesize new classes of materials for selective sorption of certain types of radionuclides in the body of mineral and polymer matrices. This will allow us to use these materials as a highly effective sorption materials with a synergetic effect for the detection, identification, immobilization and fixation of LRW radionuclides.

AbstractThe use of polyisobutylene and poly(4-dodecylstyrene) bound catalysts that contain transition metal or organocatalysts for cyclopropanation, ring-closing metathesis, and nucleophilic catalysis in flow chemistry schemes is described and compared with similar catalysts used in batch reactions. These Rh(II) carboxylate catalysts, N-heterocyclic carbene-ligated Ru(II) benzylidene catalysts, and analogs of 4-dimethylaminopyridine catalysts were used in reactions in heptane in flow and then separated in a gravity based liquid/liquid separation using a biphasic heptane/acetonitrile mixture. The less dense catalyst-containing phase in that separation was continuously used in flow with fresh substrate solution. Leaching of catalysts, yields, and turnover frequencies in these flow reactions were comparable with prior results obtained with the same phase isolable catalysts in batch reactions.

Aim: Additively manufactured (3D printed), stainless steel implants were coated with dexamethasone using gelatin, chondroitin sulfate for use in bone graft surgeries. Materials & methods: The drug and polymers were deposited on the implants with a rough surface using a high precision air brush. The gelatin-chondroitin sulfate layers were cross-linked using glutaraldehyde. Results: The drug content uniformity was within 100 ± 5%, and the thickness of the polymer layer was 410 ± 5.2 μm. The in vitro release studies showed a biphasic pattern with an initial burst release followed by slow release up to 3 days. Conclusion: These results are very promising as the slow release implants can be further tested in vivo in large animals, such as cattle and horses to prevent the inflammatory cascade following surgeries.

This article presents a study of the synthesis and characterization of new biphasic hybrid composite materials consisting of intercalated complexes (ICC) of natural mineral bentonite with copper hexaferrocyanide (phase I), which are incorporated into the bulk of the polymer matrix (phase II). It has been established that the sequential modification of bentonite with copper hexaferrocyanide and introduction of acrylamide and acrylic acid cross-linked copolymers into its volume by means of in situ polymerization promote the formation of a heterogeneous porous structure in the resulting hybrid material. The sorption abilities of prepared hybrid composite toward radionuclides of liquid radioactive waste (LRW) have been studied, and the mechanism for binding radionuclide metal ions with the components of the hybrid composition have been described.

Solid-state batteries with nonflammable inorganic solid electrolytes provide a fundamental solution for resolving safety concerns. Li7La3Zr2O12 (LLZO) has been considered as a promising candidate for solid electrolytes, due to its high Li+ conductivity and chemical/electrochemical compatibility with Li metal. However, LLZO electrolytes are known to react with H2O and CO2 to form lithium carbonates (Li2CO3) on the surface when exposed to the ambient air, resulting in the significant degradation in Li+-conduction properties. Herein, we propose an effective approach for improving the air-stability of LLZO via hydrophobic polymer encapsulation. For encapsulation of LLZO powders, polyurethane-based polymers are designed and synthesized to have high hydrophobicity and ionic conductivity by engineering soft segment and hydrophobic chain extender. Bare LLZO and polymer-encapsulated LLZO (P-LLZO) powders are subjected to accelerated durability tests (ADTs) in which the concentrations of O2, H2O, and CO2 are precisely controlled to promote the interfacial reactions. Surface characterization studies reveal that the polymer encapsulation of LLZO effectively mitigates the interfacial degradation (Li2CO3 formation) by preventing the direct contact between LLZO and H2O/CO2. Furthermore, a biphasic solid electrolyte (BSE) fabricated using ADT-tested P-LLZO powders exhibits higher ionic conductivity as compared with that of BSE with ADT-tested LLZO, proving the efficacy of the polymer encapsulation. The findings of this study would be essential in understanding the role of interfacial engineering in mitigating the degradation of Li+-conduction properties and developing highly conductive and stable LLZO solid electrolytes.

Les besoins d’allègement de poids dans le transport principalement en vue d’une réduction des émissions des gaz à effet de serre placent les composites à renfort de fibres de carbone (CFRC) comme matériaux potentiels. La fonctionnalisation de ces matériaux leur confèrerait une valeur ajoutée et de nouvelles perspectives d’application. La fonctionnalisation des composites CFRC implique de nombreux travaux de recherche qui se heurtent à une problématique de la décohésion du dépôt de surface en raison de la faible adhérence CFRC-dépôt, car les deux parties étant respectivement en polymère et en métal. Ce problème est un verrou scientifique. L’objectif de ce travail de thèse est alors de mettre au point une solution de fonctionnalisation de surface d’un composite CFRC par une technique de métallisation par collision à haute vitesse. Une partie des travaux effectués consiste à développer une structure composite hybride constituée d’une structure CFRC et d’une sous-couche composée d’une phase métallique et d’une phase polymère calibrée pour compatibiliser la structure CFRC et la technique de métallisation par projection à froid.Une partie de ce travail de thèse est consacrée à l’élaboration d’un système hybride CFRC/sous-couche biphasique superficielle en polymère/métal. Le procédé d’infusion sous vide a été mis en œuvre pour la polymérisation de ce système. La sous-couche biphasique consiste en un mélange de poudre micrométrique métallique avec de la résine thermodurcissable (époxy) ou thermoplastique (poly méthacrylate de méthyle) à différentes concentrations, permettant de produire des sous-couches de type TS-Al, TS-Cu, ou TP-Cu directement intégrées à la surface de la structure CFRC. Des essais de métallisation de ces sous-couches par projection à froid ont ensuite été réalisés, en utilisant le système de projection à basse pression Dymet 423. Des poudres de cuivre, d’aluminium, de zinc et d’étain sont choisies comme matériau de métallisation en raison de leur bonne conductivité électrique et thermique. Des poudres composites constituées d’un mélange métal/alumine ont aussi été considérées pour améliorer la formation de revêtement en tirant profit de l’effet de martelage produit par les particules d’alumine. Un revêtement (Sn + Al2O3) d’une épaisseur de 60 µm a été obtenu sur la sous-couche TS-Cu, démontrant en cela la faisabilité d’une métallisation d’une structure CFRC via la sous-couche biphasique, par projection à basse pression.Une autre partie de cette thèse porte sur une analyse phénoménologique de la réponse mécanique de la sous-couche biphasique TS en utilisant la simulation numérique. La collision à haute vitesse endommage la sous-couche à matrice thermodurcissable qui se fragmente sous l’effet de la contrainte de collision. Ce phénomène explique la difficulté de formation de revêtement sur la sous-couche à base de polymère thermodurcissable. Afin d’identifier des matériaux polymères appropriés pour une bonne tenue mécanique de la sous-couche pendant la collision à haute vitesse, une simulation sur des substrats thermoplastiques (TP et TP-Cu) a été étudiée. Les résultats montrent une pénétration des particules de Cu projetées, dans le substrat TP, en formant en cela une adhésion métal/résine par ancrage mécanique. Les particules de Cu constituant la sous-couche permettent de favoriser la déformation plastique des particules de Cu projetées, et ensuite la formation d’un revêtement. Ce constat a permis d’élaborer des essais expérimentaux de projection à froid à haute pression pour métalliser des substrats à base de matrice TP. Il en résulte une formation de revêtement pour différentes poudres (Cu sphérique, Cu dendritique, Cu + Al2O3). Le revêtement obtenu peut atteindre une épaisseur de 95 µm, 231 µm et 114 µm respectivement. Ces résultats démontrent bien la faisabilité d’une métallisation d’une structure CFRC via une sous-couche biphasique TP et une technique additive par projection à froid à haute pression
Carbon fiber reinforced composites (CFRC) have been successfully developed since decades as efficient and lightweight materials for various innovative applications and mostly for transport applications. Due to the low electrical conductivity of the polymer matrix of CFRCs, a better functionalization of such materials, such as developing a metallic coating on the CFRC structure of an aircraft, brings added values that contribute to a longer life and new performances such as the lightning strike protection (LSP) performance. The major objective of this PhD research program is to improve the metallization of a CFRC substrate by a new approach that focuses on the development of a hybrid layered structure made of CFRC and a biphasic sublayer embedded onto the top surface of this structure, prior to a cold spray metallization. To achieve this objective, the research works rely on an experimental task and a computational analysis which can be divided into three significant contributions:The first experimental part focuses on the development of a biphasic sublayer in between the CFRC substrate and the metal coating. This sublayer consists of a mixture of a polymer (Thermoset Epoxy, Thermoplastic Polymethyl methacrylate) with a micron sized metal powder (Al, Cu). The vacuum assisted resin infusion process is used to produce the hybrid CFRC with the biphasic sublayer on its top face. Prior to the cold spray metallization, the thermo-physical properties of the hybrid CFRCs/biphasic sublayer are characterized using a differential scanning calorimetry (DSC) analysis and a thermal conductivity measurement. The mechanical properties of the hybrid CFRC system are characterized by means of mechanical testing (impact test, tensile test, three-point flexural test, lap-shear adhesion test).The second part of this PhD work investigates the metallization of the hybrid system CFRC/biphasic sublayer using the low-pressure cold spray Dymet 423 system. Copper, aluminum, zinc, and tin powders are used as coating material due to their good electrical and thermal conductivity. Powder mixtures made of these metals and alumina powders (Al2O3) are considered as other potential materials for the cold spray metallization of the biphasic sublayer/CFRC system. An embedment of the cold spray powders onto the biphasic sublayer is found to ease the coating formation, except for the Cu cold spray powder. A continuous 60 μm thick coating of Sn+Al2O3 is obtained onto the biphasic TS-Cu sublayer, that shows the feasibility of surface functionalization of CFRC via a biphasic sublayer and a low-pressure cold spraying.The third part of this PhD work focuses on a phenomenological analysis of the mechanical response of the TS biphasic sublayer during the high-speed collision of the cold spray process. This part aims to depict further improvements through a computational analysis. The erosion issue of the epoxy matrix of the sublayer is found to govern the unsuccessful coating formation onto the thermoset sublayer. Therefore, to find out suitable biphasic polymer materials, a simulation of a Cu powder collision onto thermoplastic media (TP and TP-Cu) has been investigated, that shows a good embedment of the Cu powder onto the TP substrate via a mechanical interlocking (metal-to-resin bonding). The copper particles of the biphasic TP-Cu sublayer enable to promote a plastic deformation of the sprayed Cu particles and is conducive to a bonding formation and coating growth. Finally, to provide a proof of concept, experimental HPCS metallization onto biphasic sublayers made of a TP matrix are performed. A continuous coating formation of spherical Cu, dendritic Cu, and Cu+Al2O3 is obtained onto TP-Cu sublayer, with a thickness of 95 µm, 231 µm, and 114 μm respectively. Thereby, the feasibility of the metallization of CFRC via a TP biphasic sublayer and a high-pressure cold spray deposition has been demonstrated

Abstract This study aims to develop a metal-based compatibilizing sublayer on a Carbon Fiber-Reinforced Polymer (CFRP) composite to overcome the erosion issue of polymer substrate using the cold spray deposition technique. The objective is to contribute to the in-situ repair of aircraft structures. Two cases of sublayers, i.e., Al-based sublayer (1126 μm thick) and Cu-based sublayer (547 μm thick), have been prepared and co-cured with the CFRP substrates by pressure assisted molding process. Gas-atomized copper powders were deposited on a reference sample of aluminum panel (A-0) and on two functionalized composite substrates (A-1 and C-1) by a high-pressure cold spraying (HPCS) process. The results show that cold spray deposition onto the Al-based sublayer leads to a coating formation whereas the Cu-based sublayer is strongly eroded by the supersonic collision of copper powders. Scanning electronic microscope (SEM) morphologies were used to investigate the HPCS deposition mechanisms on various configurations of substrates. It was found that the high deposition efficiency of case Cu/A-0 was achieved by metallic bonding, evidenced by the significant flattening powders and agglomeration phenomenon of multiple particles. The copper particles of case Cu/A-1, encapsulated by the deformed aluminum powders, could anchor to the substrate via mechanical interlocking, whereas only pure localized fracture of epoxy and exposed broken carbon fibers were observed on the substrate of case Cu/C-1. The results demonstrated the feasibility of an Al-based sublayer-assisted cold spray process for the thermosetting CFRP composite to achieve a successful deposition of copper powders, which also emphasized the necessity to search an optimal material coupling between sublayers and coatings.

Abstract A design concept for potentially hard damage-resistant ceramic coatings on relatively soft substrates is proposed. Such coating structures are of direct relevance to biomechanical structures, especially teeth and dental crowns. In this study failure modes in bilayers and trilayers with relatively hard, brittle coating outerlayers on soft, tough substrate underlayers are evaluated. Coating/substrate systems of interest include ceramic/ceramic, ceramic/metal, and ceramic/polymer. A key element of these structures is a well-bonded interface, to prevent delamination during stressing. The objective is to arrest intrusive coating cracks in a tough sublayer, rather than merely to deflect them along a weak interface.