Solvay (Italy)

Solvents are used in every chemical process and affect its overall safety, environmental, and economic impact. Membrane processes have attracted increasing interest as sustainable alternatives to traditional technologies, being characterized by reduced energy consumption and use of chemicals. However, the most important membrane preparation techniques are often based on the use of toxic solvents, which reduces the benefit to the environment. Due to the influence of solvent properties such as viscosity, dielectric constant, polarity, and boiling point on the final features and the indispensable prerequisite of dissolving the selected polymer (at room or high temperature, depending on the technique), one of the most difficult but most interesting challenges for membrane scientists is replacing these solvents, such as N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMA), N-methyl-2-pyrrolidone (NMP), and tetrahydrofuran (THF), with safer alternatives. In this review, the most relevant steps towards the use of non-toxic solvents in membrane preparation are reported, focusing particular attention on the non-solvent induced and temperature induced phase separation (NIPS and TIPS) techniques. Supercritical CO2 (ScCO2) and ionic liquids (ILs) are promising examples of benign solvents, and their use in membrane preparation will also be described. The total replacement of toxic diluents with greener alternatives still remains at the beginning stages. However, in several cases, membranes prepared using less/non-toxic solvents achieved performance comparable to those produced with classical toxic solvents. This review offers valid support for membrane scientists who wish to reduce the environmental impact of solvent use and increase membrane processes sustainability.

Water electrolysis supplied by renewable energy is the foremost technology for producing “green” hydrogen for fuel cell vehicles. In addition, the ability to rapidly follow an intermittent load makes electrolysis an ideal solution for grid-balancing caused by differences in supply and demand for energy generation and consumption. Membrane-electrode assemblies (MEAs) designed for polymer electrolyte membrane (PEM) water electrolysis, based on a novel short-side chain (SSC) perfluorosulfonic acid (PFSA) membrane, Aquivion®, with various cathode and anode noble metal loadings, were investigated in terms of both performance and durability. Utilizing a nanosized Ir0.7Ru0.3Ox solid solution anode catalyst and a supported Pt/C cathode catalyst, in combination with the Aquivion® membrane, gave excellent electrolysis performances exceeding 3.2A·cm−2 at 1.8V terminal cell voltage (∼80% efficiency) at 90°C in the presence of a total catalyst loading of 1.6mg⋅cm−2. A very small loss of efficiency, corresponding to 30mV voltage increase, was recorded at 3A⋅cm−2 using a total noble metal catalyst loading of less than 0.5mg·cm−2 (compared to the industry standard of 2mg·cm−2). Steady-state durability tests, carried out for 1000h at 1A⋅cm−2, showed excellent stability for the MEA with total noble metal catalyst loading of 1.6mg·cm−2 (cell voltage increase ∼5μV/h). Moderate degradation rate (cell voltage increase ∼15μV/h) was recorded for the low loading 0.5mg·cm−2, MEA. Similar stability characteristics were observed in durability tests at 3A·cm−2. These high performance and stability characteristics were attributed to the enhanced proton conductivity and good stability of the novel membrane, the optimized structural properties of the Ir and Ru oxide solid solution and the enrichment of Ir species on the surface for the anodic catalyst.

Smart textiles consist of discrete devices fabricated from-or incorporated onto-fibres. Despite the tremendous progress in smart textiles for lighting/display applications, a large scale approach for a smart display system with integrated multifunctional devices in traditional textile platforms has yet to be demonstrated. Here we report the realisation of a fully operational 46-inch smart textile lighting/display system consisting of RGB fibrous LEDs coupled with multifunctional fibre devices that are capable of wireless power transmission, touch sensing, photodetection, environmental/biosignal monitoring, and energy storage. The smart textile display system exhibits full freedom of form factors, including flexibility, bendability, and rollability as a vivid RGB lighting/grey-level-controlled full colour display apparatus with embedded fibre devices that are configured to provide external stimuli detection. Our systematic design and integration strategies are transformational and provide the foundation for realising highly functional smart lighting/display textiles over large area for revolutionary applications on smart homes and internet of things (IoT).

A bstract : Membrane processes are receiving increasing attention in the scientific community and in industry because in many cases they offer a favorable alternative to processes that are not easy to achieve by conventional routes. In this context, membranes made with perfluorinated polymers are of particular interest because of the unique features demonstrated by these materials. Both highly hydrophobic and hydrophilic membranes have been developed from appropriate perfluoropolymers that were, in turn, obtained by copolymerizing TFE with special monomers available on an industrial scale. Highly hydrophobic membranes obtained from the glassy copolymers of TFE and 2,2,4‐trifluoro‐5 trifluoromethoxy‐1,3 dioxole (Hyflon ® AD) exhibit properties that make them particularly well suited for use in optical applications, in the field of gas separation, and in gas‐liquid contactors. Conditions for preparing membranes that are adequate for use in various applications are exemplified. Hydrophylic highly conductive proton exchange membranes obtained from the copolymer of TFE and a short‐side‐chain (SSC) perfluorosulfonylfluoridevinylether (Hyflon Ion) find interesting application in the field of fuel cells, especially in view of the current tendency to move to high temperature operation. The advantages offered by these hydrophobic and hydrophylic perfluorinated materials for use in membrane technology are discussed. Comparison of membrane properties and performance is made with other membranes available on the market.

OBJECTIVES: The purpose of this study was to prospectively evaluate the clinical and radiographic outcomes of immediately loaded full-arch fixed prostheses supported by a combination of axially and non-axially positioned implants in a large cohort of patients with completely edentulous jaws, up to 5 years of function. MATERIALS AND METHODS: One hundred and seventy-three edentulous patients (80 males and 93 females) were enrolled according to specific selection criteria. Each patient received a full-arch fixed prosthesis supported by two distal tilted implants and two anterior axially placed implants. The provisional functional acrylic prosthesis was delivered the same day as surgery in all cases. All cases were finalized 4-6 months later. The patients were scheduled for follow-up at 6 and 12 months of function, and annually up to 5 years. At each follow-up plaque and bleeding score was assessed and radiographic evaluation of marginal bone level was performed. RESULTS: The overall follow-up range was 4-59 months. A total of 154 immediately loaded prostheses (61 in the maxilla and 93 in the mandible) were in function for at least 1 year and were considered for the analysis. Four axially placed implants failed in the maxilla and one tilted implant in the mandible, all within 6 months of loading. No further implant failure occurred to date. Implant survival at 1 year was 98.36% and 99.73% for the maxilla and the mandible, respectively. Marginal bone loss at 1 year averaged 0.9+/-0.7 mm in the maxilla (204 implants) and 1.2+/-0.9 mm in the mandible (292 implants). No difference was found in marginal bone loss between axial and tilted implants. Plaque and bleeding scores progressively improved from 6 to 12 months. Fracture of the acrylic prosthesis occurred in 14% of total cases. CONCLUSIONS: The present preliminary results from a relatively large sample size suggest that the present technique can be considered a viable treatment option for the immediate rehabilitation of both mandible and maxilla.

Nanosized Ir-black (3 nm) and Ir-oxide (5 nm) oxygen evolution electrocatalysts showing high performance in polymer electrolyte membrane (PEM) water electrolysis based on Aquivion® short-side chain ionomer membrane are investigated to understand the role of the Ir oxidation state on the electrocatalytic activity and stability. Despite the smaller mean crystallite size, the Ir-black electrocatalyst shows significantly lower initial performance than the Ir-oxide. During operation at high current density, the Ir-black shows a decrease of cell potential with time whereas the Ir-oxide catalyst shows increasing cell potential resulting in a degradation rate of about 10 μV/h, approaching 1000 h. The unusual behaviour of the Ir-black results from the oxidation of metallic Ir to IrOx. The Ir-oxide catalyst shows instead a hydrated structure on the surface and a negative shift of about 0.5 eV for the Ir 4f binding energy after 1000 h electrolysis operation. This corresponds to the formation of a sub-stoichiometric Ir-oxide on the surface. These results indicate that a hydrated IrO2 with high oxidation state on the surface is favourable in decreasing the oxygen evolution overpotential. Modifications of the Ir chemical oxidation state during operation can affect significantly the catalytic activity and durability of the electrolysis system.

Barium titanate has been prepared by solid‐state reaction of nanocrystalline TiO 2 (70 nm) with BaCO 3 of different particle size (650, 140, and 50 nm). The results give evidence of a strong effect of the size of BaCO 3 in the solid‐state synthesis of barium titanate. The use of nanocrystalline BaCO 3 already leads to formation of the single‐phase BaTiO 3 after calcination for 8 h at 800°C. The final powder consists of primary particles of ≈100 nm, has a narrow particle size distribution with d 50 =270 nm, and no agglomerates larger than 800 nm. For the coarser carbonate, 4 h calcination at 1000°C are required and the final powder is much coarser. Solid‐state reaction of nanocrystalline BaCO 3 and TiO 2 represents an alternative to chemical preparation routes for the production of barium titanate ultrafine powders.

The first inhibition study of the mitochondrial isozyme carbonic anhydrase (CA) V (of murine origin) with a series of aromatic and heterocyclic sulfonamides is reported. Inhibition data of the cytosolic isozymes CA I and CA II and the membrane-bound isozyme CA IV with these inhibitors are also provided for comparison. Several low nanomolar CA V inhibitors were detected (KI values in the range of 4−15 nM), most of them belonging to the acylated sulfanilamide, ureido-benzenesulfonamide, 1,3,4-thiadiazole-2-sulfonamide, and aminobenzolamide type of compounds. The clinically used inhibitors acetazolamide, methazolamide, ethoxzolamide, dorzolamide, brinzolamide, and topiramate on the other hand were less effective CA V inhibitors, showing inhibition constants in the range of 47−63 nM. Some of the investigated sulfonamides, such as the ureido-benzenesulfonamides and the acylated sulfanilamides showed higher affinity for CA V than for the other isozymes, CA II included, which is a remarkable result, since most compounds investigated up to now inhibited the cytosolic isozyme CA II better. These results prompt us to hypothesize that the selective inhibition of CA V, or the dual inhibition of CA II and CA V, may lead to the development of novel pharmacological applications for such sulfonamides, for example in the treatment or prevention of obesity, by inhibiting CA-mediated lipogenetic processes.

A quantitative in situ investigation of the structure of the catalytic layer of polymer electrolyte membrane fuel cells using material-sensitive and conductive atomic force microscopy is reported. The distribution and size of the ionomer phase at the surface of the catalytic layer is retrieved from adhesion force mappings, measured at high humidity and up to 75 °C. The average ionomer layer thickness varies between 7 and 13 nm for three differently prepared samples, as concluded from the histograms. Evidence of a lamellar structure of the thinner ionomer layers is presented. A significant thinning of the ionomer layers after long-term fuel cell operation is observed.

Processes based on membranes are attracting growing interest in the scientific community and in industry, because, in many cases, they offer a favorable alternative that is not easily achievable using conventional routes. In particular, membranes made with perfluorinated polymers are very interesting, because they exhibit unique features. Hydrophilic highly conductive proton exchange membranes have been developed from the copolymer of tetrafluoroethylene (TFE) and a short-side-chain (SSC) perfluorosulfonylfluoridevinyl ether (Hyflon Ion); they have found interesting application in the field of fuel cells, especially in view of the current tendency to move to high-temperature operation. The advantages given by these hydrophilic perfluorinated materials for use in membrane technology are discussed. The properties and performance of Hyflon Ion membranes are compared with other perfluorinated membranes present on the market.

Solid and flexible ionogel-based membranes are obtained by a simple one-step process. Tuning the composition of the silica–polymer hybrid membranes allows the attainment of highly specific properties. The high ionic conductivities of the solid membranes are in the range of those of the ionic liquid electrolytes on which they are based. Good mechanical properties and high transparency from 250 to 1000 nm are also observed. The membranes are successfully applied within entirely solid lithium batteries. As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re-organized for online delivery, but are not copy-edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Abstract Polymer electrolyte fuel cell stacks assembled with Johnson Matthey Fuel Cells and SolviCore MEAs based on the Aquivion™ E79‐03S short‐side chain (SSC), chemically stabilised perfluorosulphonic acid membrane developed by Solvay Solexis were investigated at CNR‐ITAE in the EU Sixth Framework ‘Autobrane' project. Electrochemical experiments in fuel cell short stacks were performed under practical automotive operating conditions at pressures of 1–1.5 bar abs. over a wide temperature range, up to 130 °C, with varying levels of humidity (down to 18% R. H.). The stacks using large area (360 cm 2 ) MEAs showed elevated performance in the temperature range from ambient to 100 °C (cell power density in the range of 600–700 mWcm –2 ) with a moderate decrease above 100 °C. The performances and electrical efficiencies achieved at 110 °C (cell power density of about 400 mWcm –2 at an average cell voltage of about 0.5–0.6 V) are promising for automotive applications. Duty‐cycle and steady‐state galvanostatic experiments showed excellent stack stability for operation at high temperature. A performance comparison of Aquivion TM and Nafion TM ‐based MEAs under practical operating conditions showed a significantly better capability for the Solvay Solexis membrane to sustain high temperature operation.

Bis(trimethylammonium)hexane diiodide encapsulates iodine from solution and through a gas/solid reaction yielding in a predictable and controllable manner the selective formation of the rare polyiodide species I(-)...I-I...I(-), which matches in length to the chosen dication.

PURPOSE: To prospectively assess the outcome of immediate rehabilitation of extremely atrophic mandibles by a full-arch fixed bridge anchored to four implants. MATERIAL AND METHODS: Twenty patients with edentulous mandibles were included in the study. Each patient received a full-arch fixed bridge supported by two axial and two distal tilted implants. Prosthetic loading was applied within 48 hours of surgery. Patients were scheduled for follow-up every 6 months up to 2 years and annually until 5 years. Radiographic evaluation of marginal bone level change was performed at 1 year. RESULTS: All patients were followed for a minimum of 1 year (range 20-48 months, mean 30.1 months). No failures were recorded to date. The 1-year implant survival rate and prosthesis success rate were 100%. Marginal bone loss around axial and tilted implants was similar at 12-month evaluation, being, respectively, 0.6 ± 0.3 (standard deviation) mm and 0.7 ± 0.4 mm. High patient's level of satisfaction was recorded for function, phonetics, and aesthetics. CONCLUSION: This technique could be considered a viable treatment option for the rehabilitation of the atrophic mandible.

Fluoropolymers are a distinct class of per- and polyfluoroalkyl substances (PFAS), high molecular weight (MW) polymers with fluorine attached to their carbon-only backbone. Fluoropolymers possess a unique combination of properties and unmatched functional performance critical to the products and manufacturing processes they enable and are irreplaceable in many uses. Fluoropolymers have documented safety profiles; are thermally, biologically, and chemically stable, negligibly soluble in water, nonmobile, nonbioavailable, nonbioaccumulative, and nontoxic. Although fluoropolymers fit the PFAS structural definition, they have very different physical, chemical, environmental, and toxicological properties when compared with other PFAS. This study describes the composition, uses, performance properties, and functionalities of 14 fluoropolymers, including fluoroplastics and fluoroelastomers, and presents data to demonstrate that they satisfy the widely accepted polymer hazard assessment criteria to be considered polymers of low concern (PLC). The PLC criteria include physicochemical properties, such as molecular weight, which determine bioavailability and warn of potential hazard. Fluoropolymers are insoluble (e.g., water, octanol) solids too large to migrate into the cell membrane making them nonbioavailable, and therefore, of low concern from a human and environmental health standpoint. Further, the study results demonstrate that fluoropolymers are a distinct and different group of PFAS and should not be grouped with other PFAS for hazard assessment or regulatory purposes. When combined with an earlier publication by Henry et al., this study demonstrates that commercial fluoropolymers are available from the seven participating companies that meet the criteria to be considered PLC, which represent approximately 96% of the global commercial fluoropolymer market. Integr Environ Assess Manag 2023;19:326-354. © 2022 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Membrane-electrode assemblies based on chemically stabilised short-side-chain proton exchange Aquivion® membranes, prepared by extrusion or recast methods, have been investigated for operation at high current density (3–4 A cm−2) in water electrolysis cells. A thickness of 90 μm was selected for these perfluorosulfonic acid membranes in order to provide proper resilience to hydrogen crossover under differential pressure operation while allowing operation at high currents. The membranes showed proper mechanical strength for high-pressure operation and suitable conductivity to reduce ohmic losses at high current densities. Both membranes showed excellent performance in electrolysis cells by achieving a voltage efficiency better than 85% and 80% (1.85 V) at 3 and 4 A cm−2, respectively, in polarisation curves at 90 °C. A smaller surface roughness was observed from atomic force microscopy for the recast membrane compared to the extruded one. This may affect the intimate contact between the ionic clusters of the membrane and the catalyst agglomerate at the interface producing a catalytic enhancement in the activation region of the polarisation curves in the case of the recast membrane. At high cell voltages, the polarisation resistance was instead slightly lower for the cell based on the extruded membrane. Interestingly, the different characteristics of the membrane-electrodes interface produced lower recoverable losses in durability studies for the recast membrane-based electrolyser allowing stable operation at both 3 and 4 A cm−2. Hydrogen crossover analysis at a differential pressure of 20 bar showed low gas permeation through both membranes allowing for a wide load range (15–100%) and high faradaic efficiency >99% at practical current densities (1–4 A cm−2).

The function of catalytic layers in fuel cells and electrolyzers depends on the properties of the ionically conductive phase, which are most commonly perfluorinated ionomers based on Nafion and Aquivion. An analysis by atomic force microscopy reveals that the ultrathin ionomer films around Pt/C agglomerates have a thickness distribution ranging from 3.5 nm to 20 nm. Their conductivity and gas permeation properties determine the fuel cell performance to a large extend. For electrodes in Aquivion-based membrane-electrode-assemblies operation-induced structure changes were investigated by means of material- and conductivity-sensitive atomic force microscopy, infrared spectroscopy and electron-dispersive X-ray analysis. The observed thinning of the ultrathin ionomer films was mainly caused by polymer degradation deduced from reduced swelling after long-time operation and a significant loss of ionomer with operation time detected by infrared spectroscopy. From the linear thickness increase of the ultrathin films with rising humidity, a mainly layered structure of the ionomer was deduced. An influence of thickness of such ultrathin ionomer films on fuel cell lifetime was found by analysis of differently prepared membrane-electrode-assemblies, where a linear increase of irreversible degradation rate with ionomer film thickness in the electrodes of unused membrane-electrode-assemblies was found.

The heterogeneous polymerization of vinylidene fluoride in supercritical carbon dioxide has been investigated experimentally, and the obtained results have been interpreted through a detailed kinetic model. The comparison between model predictions and experimental data indicates the presence of two reaction loci: the continuous supercritical phase and the dispersed polymer phase. However, the presence of two reaction loci is not the result of the thermodynamic partitioning between two phases, but rather a kinetic effect. This in fact occurs because part of the radicals generated in the continuous phase, which are driven by thermodynamic equilibrium to diffuse to the dispersed phase, are actually terminated in the former before they can reach the latter. This provides a quantitative explanation for the bimodal molecular weight distributions often measured experimentally for this system.

Abstract Perfluoropolyether (PFPE) structures can be functionalized with acrylic groups using appropriate hydrogenated acrylic monomers: the macromers obtained are highly reactive under UV irradiation, and fluorinated polymers can be obtained. In the first part of this work is described the synthesis of new PFPE (meth)acrylic oligomers by extending OH‐terminated fluorinated chains with urethane groups and reactive acrylic functions. The photopolymerization reaction of each product is then reported followed by the characterisation of the main thermal, mechanical and surface properties of UV‐cured coatings. The polymers have good thermal resistance and fair mechanical and chemical resistance. More interestingly they show very low refractive index and low surface tension. For these latter properties the products can be advantageously used in highly demanding applications such as photonic devices and nano‐patterning. Copyright © 2011 Society of Chemical Industry

An integrated textile electronic system is reported here, enabling a truly free form factor system via textile manufacturing integration of fiber-based electronic components. Intelligent and smart systems require freedom of form factor, unrestricted design, and unlimited scale. Initial attempts to develop conductive fibers and textile electronics failed to achieve reliable integration and performance required for industrial-scale manufacturing of technical textiles by standard weaving technologies. Here, we present a textile electronic system with functional one-dimensional devices, including fiber photodetectors (as an input device), fiber supercapacitors (as an energy storage device), fiber field-effect transistors (as an electronic driving device), and fiber quantum dot light-emitting diodes (as an output device). As a proof of concept applicable to smart homes, a textile electronic system composed of multiple functional fiber components is demonstrated, enabling luminance modulation and letter indication depending on sunlight intensity.