Influence of Phase Modifiers on the Degradation of Tri-n-octylamine/dodecane Extracting Mixture by an Acidic Solution of Vanadium (V)

The kinetics of degradation of a mixture of tri-n-octylamine (extractant) and various alcoholic phase modifiers in n-dodecane in contact with acidic aqueous sulfate solutions containing vanadium (V) has been investigated. The nature of the modifier influences the kinetics of degradation and an improvement of the resistance against the chemical degradation is obtained when secondary alcohol (2-nonanol) or tertiary alcohols such as 9-octyl-9-heptadecanol are used as phase modifiers instead of 1-tridecanol. For instance, the kinetic constant of degradation is divided by one half when 9-octyl-9-heptadecanol is used as phase modifier instead of 1-tridecanol. On the contrary, the alcohols containing aromatic substituents or fluorine atoms are responsible for an increase of the chemical degradation of the extraction solvent.     

From coffee industry waste materials to skin‐friendly products with improved skin fat levels

Spent coffee grounds (SCG), which are the residue obtained from the treatment of coffee with hot water or steam, can be used for industrial applications, due to the high content in lipids. The cosmetic products might be a suitable application for these types of residues because the barrier properties of the stratum corneum (SC) are largely dependent on the intactness of the lipid lamellae that surrounds the corneocytes. The purpose of this work was to assess the feasibility of using the lipid fraction of SCG extracted with supercritical carbon dioxide in the development of new cosmetic formulations with improved skin lipids (sebum) and hydration. The use of spent coffee lipid extract in cosmetic industry seems to be a suitable approach to recycle the wastes from coffee industry. Emulsion containing 10% of the lipid fraction of SCG (SpentCofOil cream) presented promising characteristics in the improvement of sebum skin levels with a good acceptance by consumers when compared to an emulsion containing 10% w/w of green coffee oil (GreenCofOil cream) and a placebo without coffee oil (NoCofOil cream). Practical applications: In this work, the authors develop and characterize a cream containing 10% of the lipid fraction of SCG extracted with supercritical carbon dioxide with improved skin lipids (sebum) and hydration.     

Effect of Clay Modification on the Mechanism of Local Deformations in PA6 Nanocomposites

PA nanocomposites are prepared from clays organophilized with a phosphonium and an ammonium salt, and sodium montmorillonite is used as reference. The analysis of mechanical and micromechanical properties of the composites reveal that several micromechanical deformation processes occur in the PA/MMT composites. The matrix cavitates at relatively small stress. Processes related to non‐exfoliated clay structural units are initiated at larger stresses. Sound is emitted mainly by the fracture of particles, but debonding may also occur. The plastic deformation of the matrix dominates at larger stresses and deformations. The various local deformations are independent of each other and composite properties are not determined by silicate related processes but by the deformation of the matrix.

     

Analysis of adhesively-bonded T-joints by experimentation and cohesive zone models

Within the scope of adhesively-bonded joints, one of the joint types having industrial application is the T-joint, for example, in marine applications (joining of panels to the hull and connecting the glass-fibre composite hull with anti-flood panels) and aeronautical applications (wing panels, fuselage sections). This work aims to experimentally and numerically study, by cohesive zone models (CZM), the behaviour of T-joints under peel loads. The experimentally evaluated adhesives are the Araldite^® AV138 (high ultimate strength but brittle) and Araldite^® 2015 (less stress to failure but ductile and more flexible). The joint strength is evaluated with different L-shaped adherends’ thickness (t_P2). With the numerical analysis, the stress distributions, damage evolution and strength are studied. Additionally, a purely numerical study compared joints with or without adhesive filling at the curvature of the L-shaped adherends, and an extremely ductile adhesive (Sikaforce^® 7752) was additionally evaluated. The experimental tests validated the numerical results and showed that CZM is an accurate technique for the study of T-joints. It was also shown that the geometry of the L-parts, the presence of filler adhesive and the type of adhesive have a direct influence on the joint strength. In fact, in this particular joint configuration, the ductile but with lower ultimate strength adhesive Sikaforce^® 7752 clearly outperforms the two adhesives with higher mechanical properties but less ductility.     

Functionalization of wool fabric with phase‐change materials microcapsules after plasma surface modification

The use of microcapsules has increased in several different areas, namely, textile applications. They have been used as a possible means of introducing new properties, namely, in medical care by antibiotics, skin moisturizers, and other drugs and for thermal comfort. In this study, we examined the influence of dielectric barrier discharge (DBD) plasma treatment on the adhesion of phase‐change material (PCM) microcapsules on wool fabric. Several experimental techniques were used to evaluate the wool surface modification after plasma treatment and the influence of the microcapsules' resistance to washing conditions, namely, the determination of the static and dynamic contact angles, surface energy, and adhesion work; X‐ray photoelectron spectroscopy; Fourier transform infrared spectroscopy; differential scanning calorimetry; and scanning electron microscopy. Chemical and physical characterization of the wool fiber in the fabric confirmed significant surface modification. The plasma treatment greatly increased the hydrophilicity, surface energy, and adhesion work of the wool fabric; this proved that more microcapsules were adsorbed on the fabric and more microcapsules remained on the fabric surface after the washing procedures. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Flexible polymer composite electromagnetic crystals

The dielectric properties of a ceramic powder (BaTiO₃) filled thermoplastic elastomer (EPDM TPE) were investigated for use in a flexible electromagnetic crystal. Materials were produced that had a high dielectric constant (approximately 9) and low loss tangent (less than 0.01). Materials were extruded and injection molded so as to povide low‐cost processing. Mechanical and electromagnetic test results showed the effect of processing conditions on the final quality of the composite. The shear rate during processing and the number of mixing cycles were found to affect the final material characteristics significantly. An electromagnetic crystal woven from extruded rods showed good reflectivity in the 10–15 GHz region.     

Influence of textile treatment on mechanical and sorption properties of flax/epoxy composites

The aim of the present work is to study the effect of conventional textile treatments of woven flax on the mechanical properties and the water sorption of flax/epoxy composites. The flax fabrics are standard 2/2 twills. Various treatments are carried out on fabric such as mercerization, bleaching, and leaching for long fibers or on yarn such as leaching for short fibers. A model, based on a modified rule of mixture applied to composite reinforced with woven fabric, is developed to include the effect of fiber and porosity volume fractions on composite stiffness and strength. Most treatments improve tensile stiffness and strength of flax/epoxy composite and reduce composite water sorption. We prove by X‐ray fluorescence analysis, thermogravimetric analysis, and tensile tests of dry fabric that it is due to an improvement in the interfacial bonding between fibers and matrix. The best performances are achieved with bleaching and mercerization treatment. The weakest performances are obtained with the composites made with leached yarns. POLYM. COMPOS., 34:1761–1773, 2013. © 2013 Society of Plastics Engineers     

Preparation of ultra‐low‐density microcellular materials

Microcellular polymeric materials can be obtained by the polymerization of a high‐internal‐phase emulsion. These materials are good candidates as targets toward inertial confinement fusion. This application requires severe specifications, including a very low density and a small cell size. In this study, we examined the influence of parameters such as emulsification conditions, surfactant nature, and the presence of a porogen on the obtainment of those requirements. It was possible to obtain microcellular polymeric foams with apparent densities as low as 0.0126 g/cm³. However, it was difficult to obtain very low material density and still maintain a small average pore size. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2053–2063, 2005     

Rapid Discrimination of Neuromyelitis Optica Spectrum Disorder and Multiple Sclerosis Using Machine Learning on Infrared Spectra of Sera

Neuromyelitis optica spectrum disorder (NMOSD) and multiple sclerosis (MS) are both autoimmune inflammatory and demyelinating diseases of the central nervous system. NMOSD is a highly disabling disease and rapid introduction of the appropriate treatment at the acute phase is crucial to prevent sequelae. Specific criteria were established in 2015 and provide keys to distinguish NMOSD and MS. One of the most reliable criteria for NMOSD diagnosis is detection in patient’s serum of an antibody that attacks the water channel aquaporin-4 (AQP-4). Another target in NMOSD is myelin oligodendrocyte glycoprotein (MOG), delineating a new spectrum of diseases called MOG-associated diseases. Lastly, patients with NMOSD can be negative for both AQP-4 and MOG antibodies. At disease onset, NMOSD symptoms are very similar to MS symptoms from a clinical and radiological perspective. Thus, at first episode, given the urgency of starting the anti-inflammatory treatment, there is an unmet need to differentiate NMOSD subtypes from MS. Here, we used Fourier transform infrared spectroscopy in combination with a machine learning algorithm with the aim of distinguishing the infrared signatures of sera of a first episode of NMOSD from those of a first episode of relapsing-remitting MS, as well as from those of healthy subjects and patients with chronic inflammatory demyelinating polyneuropathy. Our results showed that NMOSD patients were distinguished from MS patients and healthy subjects with a sensitivity of 100% and a specificity of 100%. We also discuss the distinction between the different NMOSD serostatuses. The coupling of infrared spectroscopy of sera to machine learning is a promising cost-effective, rapid and reliable differential diagnosis tool capable of helping to gain valuable time in patients’ treatment.