Oxygen Permeation Measurements Research Articles

Oxygen Permeation Measurement of LaCrO3-based Interconnect Embedded in Real SOFCs

A method for evaluating the oxygen permeation flux through LaCrO3-based interconnects embedded in real solid oxide fuel cells (SOFCs) is proposed. The interconnect of the cell was placed in a two-chamber setup (fuel | interconnect | air), and the oxygen permeation flux was successfully determined by quantifying the amount of water vapor generated at the fuel side due to the permeation of oxygen from the air side to the fuel side. Using the proposed method, the oxygen permeation fluxes through the interconnects of the cells before and after 20,000 h of continuous operation were compared to examine the long-term stability of the LaCrO3-based interconnects. No significant difference was observed in the oxygen permeation flux before and after continuous operation, indicating that the LaCrO3-based interconnects have excellent chemical and thermal stability. In addition, the effect of oxygen permeation on energy conversion efficiency was investigated by calculating the Nernst loss. The calculations showed that oxygen permeation has almost no effect on the energy conversion efficiency.

Development of multilayer PVA-MMT and PVA-CS film structures by spin coating-assisted layer-by-layer technique: Effect of PVA, CS and MMT nanoclay orientation on oxygen barrier properties

The orientation of biopolymer macromolecules and nanoclay, specifically Montmorillonite (MMT) nanoplatelets, plays a crucial role in controlling the properties of multi-layer film structures. Understanding the impact of macromolecule and nanoclay platelets’ orientation on barrier properties of packaging films is essential. To investigate the influence of hydrogen bonding in multilayer films structures, two polymers, namely polyvinyl alcohol (PVA) and chitosan (CS), were selected and laminated nanocomposite films were fabricated using the spin coating-assisted layer-by-layer (Spin-LbL) assembly technique. This technique facilitates the production of highly oriented nanocomposite films, where polymer chains and nanoclay particles align parallel to the film surface. Multi-directional 2-D wide-angle X-ray diffraction (2D-WADX) was successfully used to accurately assess the orientation and distribution of MMT nanoplatelets. Additionally, the films underwent characterization using X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The 2D-WADX analysis revealed a parallel alignment of both the PVA chains and MMT clay nanoplatelets parallel to film surface. The XRD results confirmed the formation of intercalated nanolaminate structures, hydrogen-bonding interactions, and adjustments in the crystalline structure of PVA matrix. Through contact angle and oxygen permeability measurements, we observed that all quadri-layer film structures exhibited hydrophobic properties and reduced oxygen permeability compared to neat PVA films. Furthermore, the integration of MMT nanoclay, even at low concentrations, contributed to the development of nanocomposite films with improved oxygen barrier properties. Consequently, the quadri-layer films demonstrate great potential for food packaging applications.

Unveiling the role of K2NiF4-Structure Pr4Ni3O10+δ surface coverage in boosting oxygen permeation and suppressing membrane degradation

To probe the oxygen flux over an extended period of 1000 h, oxygen permeation measurements are performed at 700 °C for La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) coated with K2NiF4-structure Pr4Ni3O10+δ (PNO) while varying surface coverage. The optimization of PNO surface coverage, thickness, and porosity over LSCF involves the application of ultrasonic vibration of the nozzle chamber within the range of 40 kHz to 180 kHz. This is coupled with the adjustment of the gap between the nozzle exit and substrate surface, ranging from 2 cm to 9 cm. The results indicate that the PNO coating facilitated an increase in oxygen permeation and hindered the formation of secondary phases on the surface, known to cause degradation over time. When compared to bare LSCF, a minimal increase of 8 % in oxygen permeation is observed for the coated sample with a PNO loading content of 7.21 µm, denoted as PNO1. Conversely, the most significant enhancement of 74 % is seen for the loading content of 5.06 µm, referred to as PNO5. The LSCF membrane experiences a degradation of oxygen flux by 11 % after prolonged operation, significantly surpassing the mere 2.1 % degradation observed for the best-performing PNO5 membrane. This improvement is achieved by suppressing the segregated phases of SrO and CoFe2O4 on the surface. The observed enhancement in oxygen flux is attributed to the optimal surface coverage of the PNO-coated particulate, which increases the number of active sites for the oxygen reduction reaction (ORR).

Degradation Evaluation of LaCrO3-Based Interconnect on the Basis of Oxygen Permeation Measurements

Degradation of LaCrO3-based Interconnect was evaluated by comparing the oxygen permeation flux for flat tube SOFC cell before and after long term operation (20,000 hours). Oxygen permeation flux was estimated based on the amount of water vapor, which was generated as a result of oxygen permeation from the hydrogen side to the air side. The estimated oxygen permeation flux for the SOFC cell before long term operation was found to be in the range of 0.02~0.06 mL cm−2 min−1 at 750 °C. For the cell after long term operation, the oxygen permeation flux was determined to be 0.049 mL cm−2 min−1, which was almost similar with that for the cell before long term operation. This suggested that degradation of LaCrO3-based Interconnect, i.e., increase in oxygen permeation, is quite small.

Degradation Evaluation of LaCrO3-Based Interconnect on the Basis of Oxygen Permeation Measurements

Degradation of LaCrO3-based interconnect was evaluated by comparing the oxygen permeation flux for flat tube SOFC cells before and after long-term operation (20,000 hours). Oxygen permeation flux was estimated based on the amount of water vapor, which was generated as a result of oxygen permeation from the air side to the hydrogen side. The estimated oxygen permeation flux for the SOFC cell before long-term operation was found to be in the range of 0.02–0.06 mL cm−2 min−1 at 750 °C. For the cell after long-term operation, the oxygen permeation flux was found to be in the range of 0.04–0.05 mL cm−2 min−1, which was almost similar with that for the cell before long-term operation. This suggested that degradation of LaCrO3-based interconnect, i.e., increase in oxygen permeation flux, is quite small.

UV-curable polyimide/layered silicate films with improved barrier properties for the protection of semiconductor chips

Polyimide/layered silicate films can be used to protect semiconductor chips against gas and moisture permeation to prevent corrosion followed by failure of the electronic chip. The layered silicates in these films are used as barrier pigment to extend the diffusion pathway and to improve the barrier properties. However, the exfoliation of the silicates has an essential impact on the quality of the barrier. Films prepared from polyimide matrix with layered silicates were investigated as well as the distribution and orientation of silicate particles in the UV-cured film and the correlative mechanisms while hardening. The films were characterized by a variety of methods including SEM, FTIR, TGA, water vapor diffusion (WVD) and oxygen permeation measurement. The prepared films using polyimide / layered silicates nanocomposites showed a reduction of WVD and oxygen permeation of 30% and 80%, respectively. Results demonstrated that polyimide/layered silicate nanocomposite could be used as barrier coating to reduce the permeation of moisture and gases.

Pilot‐scale demonstration of novel tandem coating process: Combining dispersion and extrusion coating with enhanced barrier properties

AbstractIncreasing environmental and legislative demands have accelerated the development of new packaging materials and processes toward more sustainable alternatives. Furthermore, barrier properties of the packaging have become increasingly important, as food waste creates environmental problems. Nowadays, multilayer structures are typically used to create required barrier properties to the packages. The aim of the study was to combine dispersion and extrusion coating into consecutive tandem process to produce two‐layer structure with enhanced barrier properties. By combining two processing steps into one, time and resources are saved. The study presents demonstration of the tandem coating in pilot‐scale. The process was tested with several different materials and combinations and the processing conditions were optimized to produce optimal layer structure and properties. The properties of samples were analyzed with microscopy imaging, pinhole measurement and barrier measurements including oxygen, water vapor and grease permeation. Single layer of dispersion coatings could not produce continuous film, but the extrusion coatings filled the pinholes and enabled low permeation values. The permeabilities of the tandem coated structures were promising and generally lower than the sum of two individual layers. Moreover, the tandem coated structures produced with sustainable alternatives, performed better than traditional materials in oxygen and grease permeation measurements.

Characterization of Ruddlesden-Popper La2−xBaxNiO4±δ Nickelates as Potential Electrocatalysts for Solid Oxide Cells

Ruddlesden-Popper La2-xBaxNiO4±δ (x = 0-1.1) nickelates were prepared by a glycine-nitrate combustion route combined with high-temperature processing and evaluated for potential application as electrocatalysts for solid oxide cells and electrochemical NOx elimination. The characterization included structural, microstructural and dilatometric studies, determination of oxygen nonstoichiometry, measurements of electrical conductivity and oxygen permeability, and assessment of chemical compatibility with other materials. The formation range of phase-pure solid solutions was found to be limited to x = 0.5. Exceeding this limit leads to the co-existence of the main nickelate phase with low-melting Ba- and Ni-based secondary phases responsible for a strong reactivity with Pt components in experimental cells. Acceptor-type substitution of lanthanum by barium in La2-xBaxNiO4+δ is charge-compensated by decreasing oxygen excess, from δ ≈ 0.1 for x = 0 to nearly oxygen-stoichiometric state for x = 0.5 at 800 °C in air, and generation of electron-holes (formation of Ni3+). This leads to an increase in p-type electronic conductivity (up to ~80 S/cm for highly porous La1.5Ba0.5NiO4+δ ceramics at 450-900 °C) and a decline of oxygen-ionic transport. La2-xBaxNiO4+δ (x = 0-0.5) ceramics exhibit moderate thermal expansion coefficients, 13.8-14.3 ppm/K at 25-1000 °C in air. These ceramic materials react with yttria-stabilized zirconia at 700 °C with the formation of an insulating La2Zr2O7 phase but show good chemical compatibility with BaZr0.85Y0.15O3-δ solid electrolyte.

Evaluation of High Oxygen Permeability Ionomer (HOPI) Oxygen Permeability for Proton Exchange Membrane Fuel Cells (PEMFCs)

The performance of proton exchange membrane fuel cells (PEMFCs) is sensitive to Pt loading in the cathode catalyst layer, with lower Pt loadings significantly increasing the oxygen transport resistance of the catalyst-ionomer interface when using perfluorosulfonic acid (PFSA) ionomers. The oxygen permeability is suspected to be locally decreased at Pt interfaces due to ionomer densification caused by the Pt-ionomer interactions. However, due to the high cost of Pt, it is important to be able to reduce Pt loadings without increasing oxygen transport resistance. With this goal in mind, new precommercial high oxygen permeability ionomers (HOPIs) with blocky backbone units are being studied. These HOPIs show significantly lower local oxygen transport resistance in fuel cells as well as greater efficiency and durability. However, there was a question of whether HOPI’s higher in-situ oxygen permeability is due solely to reduced densification or if it is also due to increased bulk permeability of the films. Here we evaluated this question using a unique oxygen permeability measurement apparatus that measures the oxygen permeability of thin-films supported on mesoporous substrates. This apparatus allows films to be characterized without the polarized Pt surfaces used in other oxygen permeability diagnostics, providing insights into the bulk permeability of cast thin-films with minimized substrate effects. This presentation will present our findings of the oxygen permeability of pristine thin-film HOPIs characterized against that of the baseline PFSA ionomer. Results show that the HOPI is significantly more oxygen permeable than the baseline. This finding is supported by our molecular dynamics simulations of these ionomer films. This increased bulk film oxygen permeability indicates that a significant portion of the decreased oxygen transport resistance in the cathodes is associated with the greater bulk permeability of these films and not just local Pt interface effects.This material is based upon work supported by the U.S. Department of Energy's Office of Energy Efficiency and Renewable Energy (EERE) under the Fuel Cell Technologies Office, Award Number DE-EE0008822.

Nanocomposite Film Development Based on Chitosan/Polyvinyl Alcohol Using ZnO@Montmorillonite and ZnO@Halloysite Hybrid Nanostructures for Active Food Packaging Applications.

The global turn from the linear to the circular economy imposes changes in common activities such as food packaging. The use of biodegradable materials such as polyvinyl alcohol, natural raw materials such as clays, and food byproducts such as chitosan to develop novel food packaging films attracts the interest of industrial and institutional research centers. In this study, novel hybrid nanostructures were synthesized via the growth of zinc oxide nanorods on the surface of two nanoclays. The obtained nanostructures were incorporated with chitosan/polyvinyl alcohol composite either as nanoreinforcement or as an active agent to develop packaging films. The developed films were characterized via XRD, FTIR, mechanical, water-vapor diffusion, water sorption, and oxygen permeability measurements. Antimicrobial activity measurements were carried out against four different pathogen microorganisms. XRD indicated the formation of an intercalated nanocomposite structure for both types of nanoclays. Furthermore, improved tensile, water/oxygen barrier, and antimicrobial properties were recorded for all films compared to the pure chitosan/polyvinyl alcohol film. Overall, the results indicated that the use of the bio-based developed films led to an extension of food shelf life and could be used as novel active food packaging materials. Among them, the most promising film was the 6% wt. ZnO@halloysite.

Surface and Bulk Oxygen Kinetics of BaCo0.4Fe0.4Zr0.2-XYXO3-δ Triple Conducting Electrode Materials.

Triple ionic-electronic conductors have received much attention as electrode materials. In this work, the bulk characteristics of oxygen diffusion and surface exchange were determined for the triple-conducting BaCo0.4Fe0.4Zr0.2−XYXO3−δ suite of samples. Y substitution increased the overall size of the lattice due to dopant ionic radius and the concomitant formation of oxygen vacancies. Oxygen permeation measurements exhibited a three-fold decrease in oxygen permeation flux with increasing Y substitution. The DC total conductivity exhibited a similar decrease with increasing Y substitution. These relatively small changes are coupled with an order of magnitude increase in surface exchange rates from Zr-doped to Y-doped samples as observed by conductivity relaxation experiments. The results indicate that Y-doping inhibits bulk O2− conduction while improving the oxygen reduction surface reaction, suggesting better electrode performance for proton-conducting systems with greater Y substitution.

Poly(3‐hydroxybutyrate‐co‐3‐hydroxyhexanoate) with zinc oxide nanoparticles for food packaging

AbstractPoly(3‐hydroxybutyrate) (PHB) is a biodegradable biopolyester synthesized via bacterial fermentation from renewable resources that has received great attention over the last years for medicine and food packaging applications. However, it shows several shortcomings such as narrow processing window and a high crystallinity (>50%), which leads to brittleness and low impact resistance. To solve these drawbacks, the hydroxybutyrate units can be copolymerized with other monomers like 3‐hydroxyhexanoate to yield poly(3‐hydroxybutyrate‐co‐3‐hydroxy‐hexanoate) (PHBHHx), a copolymer with higher ductility, improved impact strength, and lower melting point. However, PHBHHx displays lower crystallinity than PHB, hence reduced stiffness, and poorer barrier properties against moisture and gases, which is a disadvantage for its use as food packaging material. In this regard, (PHBHHx)‐based bionanocomposites incorporating 0.5, 1.0, 2.0, and 5.0 wt% zinc oxide (ZnO) nanoparticles were synthesized via solution casting technique. Their morphology, mechanical, thermal, barrier, and antibacterial properties were investigated via transmission electron microscopy, tensile and impact strength tests, thermogravimetric analysis, water vapor, and oxygen permeability measurements as well as antibacterial tests. In terms of gas permeability, the optimum performance was attained at 5.0 wt% ZnO loading, with reductions in the water vapor and oxygen permeability of 45 and 33%, respectively. Conversely, the impact strength decreased with increasing ZnO concentration, leading to 25% reduction for the highest ZnO loading tested. The bionanocomposite with 5.0 wt% ZnO is a promising alternative to synthetic plastics, with an optimal balance of toughness, barrier, and antibacterial properties to be used in packaging and disposable applications such as beverage and food containers.Practical applicationsThis study analyzes the morphology, thermal, mechanical, barrier, and antibacterial properties of biodegradable nanocomposites based on PHBHHx copolymer and ZnO nanoparticles. These safe and environmentally friendly nanomaterials can be used as a sustainable alternative to synthetic plastics for food and beverage containers.

Preparation of different morphologies cellulose nanocrystals from waste cotton fibers and its effect on PLLA/PDLA composites films

In this paper, the influence of nanocellulose with different aspect ratio on the performance of PLLA/PDLA was explicit through a quantity of test results. Three different aspect ratio nanocelluloses were chemically extracted from waste colored cotton fibers. After acetylated and adding to PLLA/PDLA solution, PLLA/PDLA (LD) composites films were prepared by solution casting method and their properties were investigated by differential scanning calorimetry (DSC), polarized optical microscopy (POM), tensile testing, oxygen permeability and optical measurement. It was found that nanocellulose play a role as nucleating agent to promote crystallization and was also helpful to form the stereocomplexs crystallites. Wherein, the acetylated cellulose nanospheres (ACNS) had the most obvious effect on crystallinity enhancing. The best oxygen barrier performance of LD composites films was occurred after addition acetylated cellulose nanocrystals (ACNC). Fibrous acetylated cellulose nanofiber (ACNF) had the most influence on tensile property. Furthermore, addition of ACNS, ACNC and ACNF had hardly impact on transmittance and haze of films. It is of guiding significance for the preparation of PLA composite materials applied in different fields.

(Invited) Effects of Cobalt Co-Doping on Mixed Ion Conductivity in La(Sr)Ga(Fe)O3 for Oxygen Separation

Mixed ion conductor shows oxide ion and electronic conduction simultaneously and expecting for application to oxygen separation membrane from air. Because of significant volume change depending on oxygen partial pressure, oxygen separation membrane using mixed ion conductor has disadvantage of narrow range of oxygen partial pressure resulting in the limited permeation rate. Therefore, increased oxide ion conductivity and mechanical strength have been required for mixed ion conducting membrane for oxygen separator. In our previous study, we found that Fe doped LaGaO3 shows reasonably high oxide ion conductivity and chemical stability. In particular, La0.7Sr0.3Ga0.6Fe0.4O3 (LSGF) shows largest oxide permeation rate from air to He. In this study, for further increase in oxygen permeation rate, effects of dopant to Ga site in LSGF was investigated. Application to CH4 partial oxidation was also studied. All LSGF sample was prepared with conventional solid state reaction method using oxide as source materials. Partial substitution was performed for Ga site in LSGF and dense sample without impurity phase was confirmed by XRD measurement. For oxygen permeation measurement, La0.6Sr0.4CoO3 catalyst was coated on the surface of LSGF disk (Φ17mm diameter, 0.5mm thickness) It was found that the oxygen permeation from air to He was sensitively influenced by dopant and the oxygen permeation rate was increased as the following order, Co>Al>In>Ni>Mn at 1273 K. On the other hand, in case of Ru and Ir which is easily reduced to metallic state decreased the oxygen permeation rate significantly. Therefore, it was found that addition of 10 mol % of Co or Al is effective for increasing oxygen permeation rate of LSGF. Effects of Co in LSGF was further studied from oxygen permeation rate and the highest oxygen permeation rate was achieved at 3 mol% in Ga site of LSGC. On this optimized composition, La0.7Sr0.3Ga0.57Fe0.4Co0.03O3, shows 225 μmol min-1 cm-2 at 1273 K and this value is almost 2.5 times larger than that of LSGF. Effects of small amount of Co on electrical conductivity in LSGF were also studied. Although LSGF shows high hole conduction like log(σ/Scm-1)=0.6, the conductivity was increased by Co doping, in particular, at lower temperature. In contrast, Al doping decreases total conductivity and so, increase in oxygen permeation rate could be assigned to the increased mobility of oxide ion in LSGF. Application of Co doped LSGF to CH4 partial oxidation was further studied. Although optimized amount of Co doped for Ga site in LSGF is 3 mol%, the membrane was broken when 3 mol% doped LSGF was used for oxygen membrane. 1% Co doped LSGF was applied for oxygen permeation membrane and it was found that amount of oxygen permeation rate was 1.5 times increased comparing with LSGF. In addition, no crack was formed in membrane. The amount of oxygen permeation was achieved 364μmol cm2 min-1 which is corresponded to 8.9ml/min cm2 at 1273K. In summary, this study reveals that doping small amount of Co to Ga site of LSGF is highly effective for increasing oxygen permeation rate without decreasing chemical stability.

Structural, Mössbauer studies and oxygen permeation characteristics of Sr1-xBaxFe1-yLiyO3-ξ (x = 0, 0.5; y = 0 – 0.10) system

Perovskite ABO3-ξ cubic oxides have immense application in sensors, pumps, and oxygen permeable ceramic membrane industry. An attempt has been made here to study some sol-gel derived cobalt free Sr1-xBaxFe1-yLiyO3-ξ (x = 0, 0.5; y = 0 – 0.10) compounds from perspectives of oxygen separation from air using X-ray diffraction, Mössbauer spectroscopy, and oxygen permeability measurements. The effect of partial substitution of barium and lithium at strontium and iron sites, respectively has been examined on existing phase, oxidation states of iron, deficiency (ξ), oxygen flux density, membrane stability and possible correlations. The compounds are shown to exhibit (i) a stable cubic structure and lattice parameter (increasing in the range 3.862–3.958 Å ± 0.002 Å, Z = 1, space group Pm3m), (ii) Fe4+ → Fe3+ conversion, (iii) upsurge in anion vacancies, and (iv) enhancement in oxygen permeability (JO2 ∼ 2.45–2.81 ml cm−2.min−1 at 1000 °C) with the intended substitutions. The findings reveal natural correlation among themselves and various properties. The membranes (thickness ∼1 mm) display adequate stability at working elevated temperatures and are suitable for gas separation technology (e.g., obtaining pure oxygen from air).

Lightweight Ultra-High-Barrier Liners for Helium and Hydrogen.

Upcoming efficient air-borne wind energy concepts and communication technologies applying lighter-than-air platforms require high-performance barrier coatings, which concomitantly and nonselectively block permeation not only of helium but also of ozone and water vapor. Similarly, with the emergence of green hydrogen economy, lightweight barrier materials for storage and transport of this highly diffusive gas are very much sought-after, particularly in aviation technology. Here the fabrication of ultraperformance nanocomposite barrier liners by spray coating lamellar liquid crystalline dispersions of high aspect ratio (∼20 000) silicate nanosheets mixed with poly(vinyl alcohol) on a PET substrate foil is presented. Lightweight nanocomposite liners with 50 wt % filler content are obtained showing helium and hydrogen permeabilities as low as 0.8 and 0.6 cm3 μm m-2 day-1 atm-1, respectively. This exhibits an improvement up to a factor of 4 × 103 as compared to high-barrier polymers such as ethylene vinyl alcohol copolymers. Furthermore, ozone resistance, illustrated by oxygen permeability measurements at elevated relative humidity (75% r.h.), and water vapor resistance are demonstrated. Moreover, the technically benign processing by spray coating will render this barrier technology easily transferable to real lighter-than-air technologies or irregular- and concave-shaped hydrogen tanks.

High temperature transport properties of La0.5-xPrxBa0.5CoO3-δ perovskite (x = 0, 0.2, 0.5)

LnBaCo2O6-δ (Ln = lanthanide) are prospective materials for oxygen separation membranes. These materials show high rates of oxygen surface exchange and diffusivity, and high electrical conductivity. In this work, the La0.5-xPrxBa0.5CoO3-δ system (0 ≤ x ≤ 0.50) was studied as potential oxygen separation membrane. Samples were synthesized via a combined EDTA-citrate complexing sol-gel process at 1100 °C in air. Dense samples were obtained after 6 h calcination at 1100 °C in air. Single cubic perovskite phase (S.G.Pm3¯m) was obtained for 0 ≤ x ≤ 0.25, and tetragonal (S.G. P4/mmm) double perovskite phase for 0.30 ≤ x ≤ 0.50. Electrical conductivity (σ) was measured as a function of temperature for La0.5Ba0.5CoO3-δ (La50), La0.3Pr0.2Ba0.5CoO3-δ (La30) and Pr0.5Ba0.5CoO3-δ (La00) compounds. All the compounds have shown high electrical conductivity, reaching values between 1000 and 2000 Scm−1 at 300 °C. On increasing temperature above 300 °C, the conductivity decreases, exhibiting a metallic-like behavior, taking values of σ = 547, 385 and 714 Scm−1 at 800 °C, for La00, La30 and La50, respectively. Oxygen permeation measurements were carried out as a function of temperature between 700 and 900 °C by varying the He flux between 1 and 100 ml·min−1 on dense membranes of the same thickness (L = 1.4 mm). Ionic conductivities of 0.037, 0.054 and 0.014 Scm−1 were estimated from the oxygen permeation flux at 800 °C for La00, La30 and La50, respectively.

Sandwich-like symmetric dual-phase composite membrane with an ultra-thin oxygen separation layer and excellent durability

The Zr0.84Y0.16O1.92-La0.8Sr0.2Cr0.5Fe0.5O3-δ (YSZ-LSCrF) dual-phase composite membrane is known to possess appreciable oxygen permeability and excellent stability under stringent operation conditions. In the present study, a sandwich-like symmetric YSZ-LSCrF membrane was prepared using the phase-inversion tape casting/lamination/sintering technique. The as-prepared membrane consisted of a 5 μm thick dense oxygen separation layer sandwiched between two 300 μm thick finger-like porous layers. To promote the surface oxygen exchange, the membrane was impregnated with Sm0.2Ce0.8O2-δ (SDC) nanoparticles. The oxygen permeation flux through the membrane was measured by exposing one side of the membrane to a flowing air stream and the other side to a flowing CO stream. An oxygen permeation rate of 1.95 ml (STP) cm–2 min–1 was obtained at 900 °C. The oxygen permeation rate increased with increasing temperature as expected, and the apparent activation energy for oxygen permeation was calculated to be 29.5 kJ mol–1. The membrane remained intact after the oxygen permeation measurement and thermal cycle stability test. The sandwich-like symmetric YSZ-LSCrF membrane with an ultra-thin oxygen separation layer demonstrated desired oxygen permeability and satisfactory durability, promising for membrane reactor applications. The preparation method developed in the present study can be applied to other ceramic membranes and devices requiring the similar sandwich-like symmetric structure.

Dispersion and Performance of a Nanoclay/Whey Protein Isolate Coating upon its Upscaling as a Novel Ready-to-Use Formulation for Packaging Converters.

Studies on composition optimisation showed that the mixing of nanoclays to whey protein-isolate (WPI)-based coating formulations offers an effective strategy to reduce the oxygen permeability of coated polymer films. The scaling up of the various processing stages of these formulations was undertaken to prove their industrial feasibility. The aim was to investigate the effect of various preparation methods at different production scales (pilot- and semi-industrial scale) on the barrier performance and morphological properties of the applied nanocomposites. A nano-enhanced composition was converted into a so-called “ready-to-use” formulation by means of a solid-state pre-dispersion process using ball-milling. The process yielded a nearly dust-free, free-flowing powder containing agglomerated particles, which can easily be mixed with water. The preparation of a coating formulation using the ready-to-use granules and its upscaling for roll-to-roll converting at pilot- and semi-industrial scale was also successfully implemented. The effects of both the production at various scales and ultrasound treatment on the morphology and barrier performance of the nanocomposites were characterized by transmission electron microscopy, scanning electron microscopy, as well as oxygen permeability measurements. Results have shown that the addition of nanoclays to WPI-based coating formulations ultimately led to significantly reduced oxygen permeabilities to 0.59 cm3, 100 µm·m−2·d−1·bar−1 (barrier improvement factor, BIF of 5.4) and 0.62 cm3, 100 µm·m−2·d−1·bar−1 (BIF of 5.1) in cases of pilot- and semi-industrial-processed coatings, respectively, compared to a reference without nanoclay. In both cases, a similar degree of nanoparticle orientation was achieved. It was concluded that the solid state pre-dispersion of the nanoplatelets during the production of the ready-to-use formulation is the predominant process determining the ultimate degree of nanoparticle orientation and dispersion state.

Multilayer Flexible Packaging Materials: Relationship between Structure and Functional Properties

Flexible packaging materials is one of the huge sectors in packaging industries which feed wide range of industries etc. food, medical, beverage and others daily used products. Different structures of flexible packaging materials and its functional properties have been discussed. Ten popular multilayer laminated structures have been evaluated. These laminates are used extensively in the flexible packaging sector to demand various application purposes. The evaluation of these multilayer structures was conducted by assessment of barrier properties, mechanical properties and overall migration rates. The barrier properties were investigated by measurement of water vapor and oxygen permeability. The mechanical properties were studied through measurement the tensile strength and elongation at break %. The overall migration was tested for all samples according to EU Regulation Nr. 10/2011. The different structures showed highly satisfied functional properties that needed for each application.