scholarly journals Shear orientation of nematic phases of clay nanosheets: processing of barrier coatings

2021 ◽  
Author(s):  
Maximilian Röhrl ◽  
Judith H. Mettke ◽  
Sabine Rosenfeldt ◽  
Holger Schmalz ◽  
Ulrich Mansfeld ◽  
...  
Keyword(s):  
Effective Viscosity ◽  
High Performance ◽  
Barrier Properties ◽  
Film Coating ◽  
Particle Structure ◽  
Ordered Structures ◽  
Shear Orientation ◽  
Nematic Phases ◽  
Oriented Parallel ◽  
Plate Measurement

AbstractWhen suspensions are exposed to shear forces, the particles may form ordered structures depending on their shapes, concentrations, and the material. For some processes, e.g., for wet-film coating, it is important to know how fast these structures form in shear fields and for how long the structures persist when the shear is relaxed. To obtain information on the particle structure formation and the decay time, the effective viscosity of nematic suspensions of Na-hectorite nanosheets was investigated by rheology employing a cone-plate measurement geometry. The necessary time for the formation textured nematic films could be deduced by carrying out effective viscosity measurements at constant time steps. Information could also be obtained on the lifetime of the platelet textures when shear is relaxed. All this information was employed to identify geometrical requirements for slot dies to produce barrier liners with nanosheet layers oriented parallel to PET substrates. Thereby, we obtained green and simple coatings that are in line with state-of-the-art high-performance materials such as metalized plastic foils in terms of oxygen barrier properties.

Nano-MgO reinforced chitosan nanocomposites for high performance packaging applications with improved mechanical, thermal and barrier properties

2017 ◽  
Vol 157 ◽  
pp. 739-747 ◽  
Author(s):  
R.T. De Silva ◽  
M.M.M.G.P.G. Mantilaka ◽  
S.P. Ratnayake ◽  
G.A.J. Amaratunga ◽  
K.M. Nalin de Silva
Keyword(s):  
High Performance ◽  
Barrier Properties

Corrosion prevention prospects of polymeric nanocomposites: A review

2018 ◽  
Vol 35 (2) ◽  
pp. 181-202 ◽  
Author(s):  
Ayesha Kausar
Keyword(s):  
Corrosion Protection ◽  
High Performance ◽  
Barrier Properties ◽  
Metal Corrosion ◽  
Future Research ◽  
Polymeric Nanocomposites ◽  
Bipolar Plates ◽  
Corrosion Prevention ◽  
Covalent Interaction ◽  
Structural Parts

Corrosion is a serious problem for implementing metallic components and devices in industrial zones. Considerable effort has been made to develop corrosion prevention strategies. Initially, paints, pigments, and organic coatings have been applied to prevent metal corrosion. Consequently, conjugated polymers, epoxy resin, phenolics, acrylic polymers, and many thermoplastics as well as thermoset resins have been used to inhibit corrosion. Lately, nanofillers such as fullerene, nanodiamond, graphene, graphene oxide, carbon nanotube, carbon black, nanoclay, and inorganic nanoparticle have been introduced in polymeric matrices to harness valuable corrosion protection properties of the nanocomposite. Corrosion protection performance of a nanocomposite depends on nanofiller dispersion, physical and covalent interaction between matrix/nanofiller and nanofiller adhesion to the substrate. Moreover, a high performance anti-corrosion nanocomposite must have good barrier properties, and high scratch, impact, abrasion, and chemical resistance. Thus, polymeric nanocomposites have been found to prevent corrosion in aerospace and aircraft structural parts, electronic components, bipolar plates in fuel cells, and biomedical devices and systems. However, numerous challenges need to be addressed in this field to attain superior corrosion resistant nanocomposites. Future research on polymer nanocomposites has the potential to resolve the current challenges of metal corrosion through entire replacement of metal-based materials with advanced nanomaterials.

Effect of Zr Diffusion Barrier Properties on the Irradiation Performance of U-10Mo Monolithic Fuel Plate

2019 ◽  
Author(s):  
Walid Mohamed ◽  
Hakan Ozaltun ◽  
Hee Seok Roh
Keyword(s):  
Mechanical Properties ◽  
Diffusion Barrier ◽  
High Performance ◽  
Mechanical Performance ◽  
Plate Thickness ◽  
Barrier Properties ◽  
Element Analysis ◽  
Uranium Fuel ◽  
High Enrichment ◽  
Irradiation Performance

Abstract The most recent design of U-Mo monolithic fuel as adopted by the U.S. for the conversion of its High Performance Research Reactors (USHPRR) from high enrichment uranium (HEU) to low enrichment uranium fuel (LEU, < 20% U235) consists of a high density (LEU) U-10Mo fuel sandwiched between Zirconium (Zr) diffusion barriers and encapsulated in aluminum (AA6061) cladding. In this work, finite element analysis (FEA) was used to evaluate effect of Zr diffusion barrier properties on the thermal and mechanical performance of a U-10Mo monolithic fuel plate by considering possible variation in thermal and mechanical properties of the Zr diffusion barrier. Possible variation in thermo-mechanical properties of the Zr diffusion barrier were determined and a simulation matrix was designed accordingly. Analyses of simulation results included determination of global peak stresses in the fuel, Zr diffusion barrier, and cladding sections as well as the plate thickness profile at a transverse section toward the top side of the plate. Results showed that variation in yield stress, elastic modulus and thermal conductivity of the Zr diffusion barrier has negligible effect on the thermal and mechanical performance of the monolithic fuel plate. The effect of variation in these properties was found to be limited to the barrier section itself, which may be attributed to the relatively smaller thickness of that section compared to the fuel and cladding sections of the fuel plate.

Change of particle structure of sewage sludges during mechanical and biological processes with regard to the dewatering result

1997 ◽  
Vol 36 (4) ◽  
pp. 293-306 ◽  
Author(s):  
Thomas Nellenschulte ◽  
Rolf Kayser
Keyword(s):  
Total Mass ◽  
High Performance ◽  
Suspended Solids ◽  
Biological Process ◽  
Waste Activated Sludge ◽  
Biological Processes ◽  
Small Particles ◽  
Particle Structure ◽  
Integral Property ◽  
Wastewater Sludges

Particle size seems to be the most important parameter, to describe the dewatering behaviour and result of sludges. But there are many other parameters, which can influence the dewatering result. The dewatering result of a sludge depends on the type of sludge, the mechanical and biological process. Out of the numerous parameters to characterize wastewater sludges five were selected, which describe the properties of the particulate matter. These parameters are the suspended solids (SS), the volatile suspended solids (VSS), the density of the particles (ρ), the fraction of small particles (fines) and a new parameter, called φ-value, which is the ratio of the mass of waste activated sludge to the total mass of sludge. The tested sludges were analysed for the Zeta Potential, but there could not be found a correlation between this parameter and the dewatering result. Combining the parameters in a model led to an overall sludge parameter, the so-called “Integral Property Parameter, fE”. A correlation between the fE-values and the dewatering results of municipal sludges (n = 49) can be found. A proposal was made to transfer the experimental results to a full scale dewatering process with high performance centrifuges.

scholarly journals Ordered Structures of High-Performance Propylene/Ethylene-Propylene Rubber Polymer Blends.

1995 ◽  
Vol 52 (2) ◽  
pp. 90-96 ◽  
Author(s):  
Takao NOMURA ◽  
Takeyoshi NISHIO ◽  
Hideaki TANAKA ◽  
Kenji MORI
Keyword(s):  
Polymer Blends ◽  
High Performance ◽  
Ordered Structures ◽  
Ethylene Propylene ◽  
Ethylene Propylene Rubber

scholarly journals Flow Velocity and Effective Viscosity of a Fluid Containing Rigid Cylindrical Inclusions

2005 ◽  
Vol 60 (6) ◽  
pp. 401-407 ◽  
Author(s):  
Siegfried Hess
Keyword(s):  
Effective Viscosity ◽  
Volume Fraction ◽  
Dimensional Problem ◽  
Flow Properties ◽  
Cylindrical Inclusions ◽  
Dilute Suspension ◽  
Oriented Parallel ◽  
Relative Change ◽  
Special Case

The determination of the flow properties of a fluid containing a cylindrical inclusion with its long axis oriented parallel to the vorticity direction is a 2-dimensional problem which is treated as a special case in a calculation of the corresponding D-dimensional problem. The velocity and pressure are obtained from the solution of the equations of hydrodynamics where D-dimensional multipole potential tensors are used. The effective viscosity of a dilute suspension is evaluted via the entropy production, as suggested by Einstein, and via an effective stress tensor. The relative change of the viscosity is proportional to the volume fraction. For D = 2 the proportionality factor Z is found to be 2 and 3 when the inclusion rotates with an angular velocity equal to the vorticity and when the inclusion does not rotate, repectively. The corresponding results for D=3 are the well known number Z = 2.5 and Z = 4.

A review of high performance polymer nanocomposites for packaging applications in electronics and food industries

2019 ◽  
Vol 36 (1) ◽  
pp. 94-112 ◽  
Author(s):  
Ayesha Kausar
Keyword(s):  
High Performance ◽  
Barrier Properties ◽  
Inorganic Nanoparticles ◽  
Nanocomposite Films ◽  
Permeability Barrier ◽  
Packaging Materials ◽  
Polymeric Nanocomposites ◽  
Microbial Characteristics ◽  
High Performance Polymer ◽  
Food And Beverage

This article addresses advances in polymeric nanocomposites for packaging applications. Synthetic and biodegradable polymers have been reinforced with carbon nanotube, graphite, graphene and derived nanofiller, nanoclay, and inorganic nanoparticles to form high performance packaging materials. Polymeric nanocomposites possess markedly improved packaging properties including oxygen permeability, moisture permeability, barrier properties, solvent resistance, thermal stability, biological features, anti-microbial characteristics, non-flammability, and mechanical robustness. Performance of nanocomposite films and packaging is dependent on how well the nanofiller is dispersed in matrices. Modified nanofillers have been used to impart the desired functional properties to the packaging materials. Technical packaging applications in electronics and food and beverage industries are discussed. Using appropriate polymer, functional nanofiller, and fabrication techniques may represent inspiring routes for creating innovative packaging materials with enhanced mechanical, thermal, and barrier performances.

scholarly journals Manufacturing of Food Packaging Based on Nanocellulose: Current Advances and Challenges

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1726
Author(s):  
Ghislain Fotie ◽  
Sara Limbo ◽  
Luciano Piergiovanni
Keyword(s):  
High Performance ◽  
Food Packaging ◽  
Coating Layer ◽  
Scale Up ◽  
Barrier Properties ◽  
Synthetic Polymers ◽  
Layer By Layer ◽  
Gas Barrier ◽  
Industrial Manufacturing ◽  
Made In

Nowadays, environmental pollution due to synthetic polymers represents one of the biggest worldwide challenges. As demonstrated in numerous scientific articles, plant-based nanocellulose (NC) is a biodegradable and nontoxic material whose mechanical, rheological, and gas barrier properties are competitive compared to those of oil-based plastics. However, the sensitivity of NC in humid ambient and lack of thermosealability have proven to be a major obstacle that hinders its breakthrough in various sectors including food packaging. In recent years, attempts have been made in order to provide a hydrophobic character to NC through chemical modifications. In addition, extensive works on nanocellulose applications in food packaging such as coating, layer-by-layer, casting, and electrospinning have been reported. Despite these enormous advances, it can easily be observed that packaging manufacturers have not yet shown a particular interest in terms of applicability and processability of the nanocellulose due to the lack of guidelines and guarantee on the success of their implementation. This review is useful for researchers and packaging manufacturers because it puts emphasis on recent works that have dealt with the nanocellulose applications and focuses on the best strategies to be adopted for swift and sustainable industrial manufacturing scale-up of high-performance bio-based/compostable packaging in replacement of the oil-based counterparts used today.

Barrier properties of high performance PMMA-silica anticorrosion coatings

2020 ◽  
Vol 138 ◽  
pp. 105398 ◽  
Author(s):  
Andressa Trentin ◽  
Andressa de L. Gasparini ◽  
Flávio A. Faria ◽  
Samarah V. Harb ◽  
Fábio C. dos Santos ◽  
...  
Keyword(s):  
High Performance ◽  
Barrier Properties ◽  
Anticorrosion Coatings

Field Assessment of FBE-Coated Pipelines and the Implications for Stress Corrosion Cracking

2002 ◽  
Author(s):  
Fraser King ◽  
Yufeng Cheng ◽  
Linda Gray ◽  
Brent Drader ◽  
Robert Sutherby
Keyword(s):  
High Performance ◽  
Electrochemical Impedance ◽  
Surface Preparation ◽  
Field Measurements ◽  
Barrier Properties ◽  
Pipe Surface ◽  
Good Surface ◽  
Surface Residual Stresses ◽  
Eis Measurements ◽  
Term Performance

One proposed method for preventing the initiation of SCC on pipelines is through the use of high-performance coatings in conjunction with effective cathodic protection. High-performance coatings include fusion bonded epoxy (FBE), urethanes, liquid epoxies, extruded polyethylene, and multi-layer coatings. This paper reports the results of a CEPA-sponsored project to determine the long-term performance of FBE coatings on underground pipelines using in situ field measurements. The barrier properties of FBE coatings were measured after several years field service using Electrochemical Impedance Spectroscopy (EIS). Measurements were made on four FBE-coated pipelines that had been exposed for periods of between 5 and 20 years. The coatings studied included three different formulations from two different manufacturers. A variety of site, soil and CP conditions were also examined. The combination of EIS measurements and analyses of trapped water samples demonstrated that the FBE coatings continued to perform well after having been exposed for up to 20 years. Although some blistering and disbondment was observed in some cases as a result of poor application and storage procedures, in all cases the pipe surface was still protected either by the coating itself or by the joint action of the CP system and the CP-compatible FBE coating. The results of this study provide strong evidence that FBE-coated pipelines should not be susceptible to the initiation of SCC, due to (i) the barrier properties of the coating, (ii) the CP-compatible nature of the coating, and (iii) good surface preparation techniques that involve the removal of millscale and the introduction of compressive surface residual stresses.

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