Use Of Organic Binders Research Articles

WDXRF Analysis of White Colour Pigments Used by Ancient Artists in Central Tanzania Rock Paintings

In central Tanzania, there are large numbers of ancient rock paintings which have been drawn mostly on shelter rocks. Different colours were used in the paintings including white paint. The pigments and the material used by ancient artists in making these colours were not known. This study aimed to determine the composition of the white colour and suggests the pigments and materials used in making the white colour. A technique namely WDXRF was used to determine the composition of white paint in order to suggest the pigment used while a CHN elemental analyser was used to determine the presence and amount of organic carbon in the samples. The results from the analysis of the rock sample were compared to the results of the analysis of the paint sample. White colour was found to be from chalk (CaCO3) and gypsum (CaSO4X2H2O). Both pigments were found to contain some amount of organic carbon in different concentration. Organic carbon in the pigment is related to the use of organic binders during the preparation of the colour.

The Characterization of the Materials Used by Gino Severini in his 20th C Wall Paintings at Semsales in Switzerland

The modern decoration of the Saint Nicolas de Myre Church at Semsales (1924–1926), is the first by renowned Italian artist Gino Severini in Switzerland. Following archival research and visual examination, the materials and the techniques used by Severini for the wall paintings of this church were examined through a multi-technique analytical approach that included both non-invasive and invasive investigations. Archival research revealed lists of some of the materials purchased for the church and notes of the artists. In situ investigations included imaging methods and point analyses (X-ray fluorescence and reflection FT-IR spectroscopy). Based on non-invasive results, a limited number of representative samples were collected for laboratory invasive analyses (SEM-EDS, FTIR-FPA imaging, μ-Raman and GC-MS) to characterize the stratigraphy and the composition of the paintings. Results were coherent with artist’s notes and revealed protein-based binders, i.e. animal glue and casein, exclusively on the Trinity mural (in the apse) confirming the use of a secco technique. All the other wall paintings analyzed at Semsales are painted without the use of organic binders. These findings, integrated with archival researches and the visual examination by conservators, provided significant insights into the materials and techniques used by Gino Severini in his first Swiss murals.

Efficient dye-sensitized solar cells (DSSCs) through atmospheric pressure plasma treatment of photoanode surface

Atmospheric pressure plasma (APP) source was used for surface activation of polyetherimide (PEI) polymer substrate for dye-sensitized solar cells (DSSCs) fabrication. Changes in the water contact angle (WCA) and FE-SEM analysis of PEI samples before and after plasma treatment were used to assess the level of polymer surface activation. The changes improved the power conversion efficiency (PCE) of DSSC on PEI substrate. Radio frequency (RF) magnetron sputtering was used to deposit indium tin oxide (ITO) on the substrate at a thickness of 100 ​nm.TiO2-P25 powder was used in the preparation of the photoanode paste without the use of organic binder and doctor blade method was used for the deposition of the TiO2 paste. A reasonable increment in the PCE of about ca.60% from the plasma treated substrate was achieved when compared with the untreated substrate. This suggests that DBD plasma modification of flexible substrates has a significant favorable impact on DSSC efficiency. The charge transfer property of the cells was determined using electrochemical impedance spectroscopy (EIS). The Nyquist plot of EIS for treated substrate-based DSSC showed lower charge transfer resistance than the untreated substrate-based DSSC due to improved interconnecting path for electron transport.

Study of Droplet Diffusion in Hydrothermal-Assisted Transient Jet Fusion of Ceramics

Abstract Hydrothermal-assisted transient jet fusion (HTJF) is a powder-based additive manufacturing (AM) method of ceramics, which utilizes a water-mediated hydrothermal mechanism to fuse particles together, eliminating the use of organic binders in forming green bodies and thereby contributing to high green-density parts (>90%) advantageous for fabricating functional materials with high performance. In the HTJF process, a transient solution such as water is selectively deposited into a powder bed in a layer-by-layer fashion followed by a hydrothermal fusion process. Upon the ejection and deposition of a droplet of the transient solution on the surface of the powder bed, the diffusion behavior of the liquid significantly influences the particle fusion and the fabrication accuracy of the HTJF process. Precise control of the liquid diffusion in the powder bed is critical for the fabrication of ceramic structures with both high density and accuracy. In this paper, the dependence of transient solution diffusion on different process parameters (i.e., powder packing density, droplet size, pressure, etc.) in the HTJF process were studied. Both numerical modeling and experimental methods were used to quantify the relationships between processing parameters and diffusion profiles of transient solution droplets (e.g., diffusion width/depth). Optimum processing conditions were identified to mitigate the undesired diffusion of transient solution droplets in the powder bed.

Briquetting of Fine‐Grained Residues from Iron and Steel Production Using Organic and Inorganic Binders

The Midrex process produces metallurgical residues in the form of dust, sludge, and fines. As these have high iron content, herein, the aim is to recycle the residues and use them as an educt in the Midrex process, thus closing the material cycle and increasing raw material efficiency. Briquetting of these materials with binder is one possibility to prepare them for the use as an educt in the Midrex process. Experiments are conducted to test the suitability of the organic binders starch and cellulose for briquetting. Furthermore, tests with the inorganic bentonite are included for comparison. Briquettes are generally characterized by high strength. However, compared with iron oxide pellets, they have a low porosity and thus a higher apparent density, and consequently, a worse reducibility. The use of organic binders should improve the reducibility. The iron oxides are in close contact with the C‐carrier of the organic binder so that a solid–solid phase direct reduction can take place. Furthermore, the solid carbon reacts to CO, and thus, increases the presence of reducing gas in the enlarged pores of the briquettes, and should therefore increase the degree of reduction.

Efficient Bifunctional Catalytic Electrodes with Uniformly Distributed NiN2 Active Sites and Channels for Long-Lasting Rechargeable Zinc-Air Batteries.

Freestanding bifunctional electrodes with outstanding oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) properties are of great significance for zinc-air batteries, attributed to the avoided use of organic binder and strong adhesion with substrates. Herein, a strategy is developed to fabricate freestanding bifunctional electrodes from the predeposited nickel nanoparticles (Ni-NCNT) on carbon fiber paper. The steric effect of monodispersed SiO2 nanospheres limits the configuration of carbon atoms forming 3D interconnected nanotubes with uniformly distributed NiN2 active sites. The bifunctional electrodes (Ni-NCNT) demonstrate ideal ORR and OER properties. The zinc-air batteries assembled with Ni-NCNT directly exhibit extremely outstanding long term stability (2250 cycles with 10 mA cm-2 charge/discharge current density) along with high power density of 120 mV cm-2 and specific capacity of 834.1 mA h g-1 . This work provides a new view to optimize the distribution of active sites and the electrode structure.

High-strength electrospun carbon nanofibrous mats prepared via rapid stabilization as frameworks for Li-ion battery electrodes

Carbon nanofibrous nonwoven mats (CNFMs) prepared via electrospinning offer excellent electrical and structural properties and have been used as frameworks for electrodes in electrochemical energy storage devices. However, lack of mechanical strength hinders the broad applications of CNFMs in flexible electronics or industry use. In this work, a rapid stabilization method is developed to prepare high-strength and flexible CNFMs. Studies of the effects of stabilization time on the structures of the stabilized polyacrylonitrile (PAN) nanofibers and the subsequent carbon nanofibers reveal that there is an optimal stabilization time for making high-strength CNFMs. Long stabilization time results in excessive oxidation of the stabilized PAN nanofibers and unwanted defects in the carbon nanofibers. Short stabilization time results in carbon nanofibers with less crystalline structures due to insufficient formation of the thermally stable ladder-like structure. Robust and flexible CNFM with the highest tensile strength of 192.7 MPa is obtained using an optimized total stabilization time of 40 min. To demonstrate the application of the flexible CNFMs, they are fabricated as an electrode framework to load TiO2 nanoparticles without use of organic binders. Lithium ion half-cell based on this electrode demonstrates superior rate cycling performance owning to the porous structure and highly conductive fibrous carbon network of CNFM.

Influence of Binder Type on Color Characteristics of Cotton Fabric Colored with a Photochromic Colorant

ABSTRACTPhotochromic colorants change rapidly and reversibly from colorless to colored state when activated by ultraviolet radiation. They can be applied on textile substrates with use of organic binders. Different type of binders and their concentration may have a significant effect on color development and other related properties. In this work, a study of the effect of binder type at different concentrations on the color development, wash fastness and some comfort characteristics is undertaken. It was found that while these properties vary with binder type and concentration, the best color development is obtained at an optimum concentration of 5% binder. The presence of binder may affect comfort related properties of the fabrics, such as stiffness, water absorbency, air permeability, sometimes quite adversely. Hence a careful selection of the binder type is needed depending on the most important requirement in the colored fabrics.

Nanosized core–shell structured graphene–MnO2nanosheet arrays as stable electrodes for superior supercapacitors

Directly fabricating vertically standing graphene–manganese dioxide (MnO2) nanoparticle hybrids as electrode materials remains a challenge, especially so without the use of organic binders.

Micro FTIR imaging for the investigation of deteriorated organic binders in wall painting stratigraphies of different techniques and periods

This work deals with the detection and imaging of metal oxalates/carboxylates in the paint layers of ancient wall paintings and with the investigation of their possible association with the ageing of organic substances used as binding media in the original painting. This assumption is investigated employing Fourier transform infrared (FTIR) imaging on several case studies; starting with a thin section of the paint stratigraphy extracted from extensively deteriorated post-Byzantine murals, painted with an oil binder. Metal carboxylates and oxalates show their maximum concentration at the interface of free fatty acids and pigment particles, indicating a possible origin of their formation. Then, the methodology was applied in paint thin sections, originating from Prehistoric, Roman and Hellenistic wall paintings. In these case studies, metal oxalates detected within the paint layers were explored regarding their relation to the use of an organic binder in the wall paintings. The chemical images of calcium oxalates in the paint layers of the Prehistoric wall paintings was a trigger for further laborious investigation on numerous samples, which resulted in revealing the spectrum of an aged proteinaceous binding medium. Thereafter, the distribution of metal oxalates within the paint layers of the samples from the Roman and Hellenistic wall paintings, unaffected by any later intervention, was assumed as an indirect indication of the use of an original organic binder.

Production of porous ceramic materialusing different sources of alumina and calcia

Numerous papers and publications report the use of microporous calcium hexaluminate (CaO.6Al2O3; CA6) as a key raw material for high temperature insulating materials. This material has unique properties with respect to chemical purity and mineral composition. Another important property of CA6 is its structure, which consists of platelet-shaped crystals that interlock. The free distance between the crystals defines the microporous structure. The low density in combination with the micropores hampers heat transfer by radiation at temperatures exceeding 1000 oC and results in a low thermal conductivity. Given the advantages presented by this material, it is necessary to understand the formation mechanism of CA6 grains in order to better develop the potential applications of this material. CA6 can be fabricated using organic binders to consolidate the Al2O3-CaCO3 powder mixture and to provide green strength so that a green body can be formed and retains the desired shape before heating. However, these organic binders must be completely thermally decomposed so that they do not remain in the sintered body as carbon or ash. Moreover, the use of organic binders releases large volumes of gases such as carbon dioxide from the green body during heating. Therefore, an eco-friendly ceramic fabrication process has been developed that employs an inorganic binder (hydraulic alumina). The aim of the present work was to study the synthesis of porous calcium-hexaluminate ceramics using calcined alumina or hydraulic alumina combined with different sources of calcia (CaCO3 and Ca(OH)2) at different temperatures. The materials produced were characterized by X-ray diffraction, scanning electron microscopy, apparent porosity and mercury intrusion porosimetry. The materials produced by hydraulic alumina presented higher porosity and larger pores compared to those produced from calcined alumina

Bioactive glass-reinforced bioceramic ink writing scaffolds: sintering, microstructure and mechanical behavior

The densification of pore struts in bioceramic scaffolds is important for structure stability and strength reliability. An advantage of ceramic ink writing is the precise control over the microstructure and macroarchitecture. However, the use of organic binder in such ink writing process would heavily affect the densification of ceramic struts and sacrifice the mechanical strength of porous scaffolds after sintering. This study presents a low-melt-point bioactive glass (BG)-assisted sintering strategy to overcome the main limitations of direct ink writing (extrusion-based three-dimensional printing) and to produce high-strength calcium silicate (CSi) bioceramic scaffolds. The 1% BG-added CSi (CSi-BG1) scaffolds with rectangular pore morphology sintered at 1080 °C have a very small BG content, readily induce apatite formation, and show appreciable linear shrinkage (∼21%), which is consistent with the composite scaffolds with less or more BG contents sintered at either the same or a higher temperature. These CSi-BG1 scaffolds also possess a high elastic modulus (∼350 MPa) and appreciable compressive strength (∼48 MPa), and show significant strength enhancement after exposure to simulated body fluid—a performance markedly superior to those of pure CSi scaffolds. Particularly, the honeycomb-pore CSi-BG1 scaffolds show markedly higher compressive strength (∼88 MPa) than the scaffolds with rectangular, parallelogram, and Archimedean chord pore structures. It is suggested that this approach can potentially facilitate the translation of ceramic ink writing and BG-assisted sintering of bioceramic scaffold technologies to the in situ bone repair.

ALTERNATIVE BINDERS TO BENTONITE FOR IRON ORE PELLETIZING : PART II : EFFECTS ON METALLURGICAL AND CHEMICAL PROPERTIES

This study was started to find alternative binders to bentonite and to recover the low preheated and fired pellet mechanical strengths of organic binders-bonded pellets. Bentonite is considered as a chemical impurity for pellet chemistry due to acid constituents (SiO2 and Al2O3). Especially addition of silica-alumina bearing binders is detrimental for iron ore concentrate with high acidic content. Organic binders are the most studied binders since they are free in silica. Although they yield pellets with good wet strength; they have found limited application in industry since they fail to give sufficient physical and mechanical strength to preheated and fired pellets. It is investigated that how insufficient preheated and fired pellet strengths can be improved when organic binders are used as binder. The addition of a slag bonding/strength increasing constituent (free in acidic contents) into pellet feed to provide pellet strength with the use of organic binders was proposed. Addition of boron compounds such as colemanite, tincal, borax pentahydrate, boric acid together with organic binders such as CMC, starch, dextrin and some organic based binders, into magnetite and hematite pellet mixture was tested. After determining the addition of boron compounds is beneficial to recover the low pellet physical and mechanical qualities in the first part of this study, in this second part, metallurgical and chemical properties (reducibility - swelling index – microstructure – mineralogy - chemical content) of pellets produced with combined binders (an organic binder plus a boron compound) were presented. The metallurgical and chemical tests results showed that good quality product pellets can be produced with combined binders when compared with the bentonite-bonded pellets. Hence, the suggested combined binders can be used as binder in place of bentonite in iron ore pelletizing without compromising the pellet chemistry.

Use of organic binder in coke making

Phenol based resol type resin was used as a binder in coke making and the effects of the binder on coke strength studied. The results have indicated that addition of binder improves the coke hot strength (CSR) and coke cold strength (M40). The optimum quantity was determined as 0·3%. Petrographic analysis shows an agreement with the coke strength.

Substances for reduction of the contamination of feed by mycotoxins: a review

The global occurrence of mycotoxins is considered to be a major risk factor for human and animal health. Contamination of different agricultural commodities with mycotoxins still occurs despite the most strenuous prevention efforts. As a result, mycotoxin contaminated feed can cause serious disorders and diseases in farm animals. A number of approaches, such as physical and chemical detoxification procedures, have been used to counteract mycotoxins. However, only a few of them have practical application. A recent and promising approach to protect animals against the harmful effects of mycotoxin contaminated feed is the use of substances for reduction of the contamination of feed by mycotoxins. These substances, so-called mycotoxin binders (MB), are added to the diet in order to reduce the absorption of mycotoxins from the gastrointestinal tract and their distribution to blood and target organs, thus preventing or reducing mycotoxicosis in livestock. Recently, the use of such substances as technological feed additives has been officially allowed in the European Union. The efficacy of MB appears to depend on the properties of both the binder and the mycotoxin. Depending on their mode of action, these feed additives may act either by binding mycotoxins to their surface (adsorption), or by degrading or transforming them into less toxic metabolites (biotransformation). Biotransformation can be achieved by mycotoxin-degrading enzymes or by microorganisms producing such enzymes. Various inorganic adsorbents, such as hydrated sodium calcium aluminosilicate, zeolites, bentonites, clays, and activated carbons, have been tested and used as MB. An interesting alternative to inorganic adsorbents for the detoxification of mycotoxins is the use of organic binders, such as yeast cell wall components, synthetic polymers (cholestyramine, polyvinylpyrrolidone), humic substances and dietary fibres. This paper gives an overview of the current knowledge and situation in the field of MB. The most important types of MB, mechanism of their action, and their application as a part of general strategy to counteract mycotoxins are described in this review. Recent advances in the use and study of MB, as well as data of their in vitro and in vivo effectiveness are given. Problems, potential, current trends and perspectives associated with the use of MB are discussed as well in the review.

Pelletization of magnetite ore with colemanite added organic binders

A new generation binder consisting of an organic binder and a borate salt was tested as an alternative to bentonite in magnetite ore pelletization. Carboxyl methyl cellulose (CMC), Ciba DPEP06-0007 and corn starch, and calcined colemanite were used as organic binders and the borate salt, respectively. They were added to the pellet feed separately and in different combinations at several addition levels. It was found that the use of organic binders is sufficient in terms of wet pellet quality; however, they fail to render the required compressive strength to pre-heated and fired pellets. Therefore, organic binders and calcined colemanite were used together so that wet pellets, pre-heated and fired pellets would be of the required quality. The results showed that the use of an organic binder together with calcined colemanite indeed yielded pellets with equal or better wet and indurated pellet qualities compared to the pellets produced with bentonite binder alone.

Ultrahigh-power micrometre-sized supercapacitors based on onion-like carbon

Electrochemical capacitors, also called supercapacitors, store energy in two closely spaced layers with opposing charges, and are used to power hybrid electric vehicles, portable electronic equipment and other devices. By offering fast charging and discharging rates, and the ability to sustain millions of cycles, electrochemical capacitors bridge the gap between batteries, which offer high energy densities but are slow, and conventional electrolytic capacitors, which are fast but have low energy densities. Here, we demonstrate microsupercapacitors with powers per volume that are comparable to electrolytic capacitors, capacitances that are four orders of magnitude higher, and energies per volume that are an order of magnitude higher. We also measured discharge rates of up to 200 V s(-1), which is three orders of magnitude higher than conventional supercapacitors. The microsupercapacitors are produced by the electrophoretic deposition of a several-micrometre-thick layer of nanostructured carbon onions with diameters of 6-7 nm. Integration of these nanoparticles in a microdevice with a high surface-to-volume ratio, without the use of organic binders and polymer separators, improves performance because of the ease with which ions can access the active material. Increasing the energy density and discharge rates of supercapacitors will enable them to compete with batteries and conventional electrolytic capacitors in a number of applications.

Supercapacitors Based on Metal Electrodes Prepared from Nanoparticle Mixtures at Room Temperature

Films comprising Au and Ag nanoparticles are transformed into porous metal electrodes by desorption of weak organic ligands followed by wet chemical etching of silver. Thus prepared electrodes provide the basis for supercapacitors whose specific capacitances approach 70 F/g. Cyclic voltammetry measurement yield “rectangular” I−V curves even at high scan rates, indicating that the supercapacitors have low internal resistance. Owing to this property, the supercapacitors have a high power density ∼12 kW/kg, comparable with that of the state-of-the-art carbon-based devices. The entire assembly protocol does not require high-temperature processing or the use of organic binders.

DETERMINATION OF PIGMENTS AND BINDERS IN POMPEIAN WALL PAINTINGS USING SYNCHROTRON RADIATION – HIGH‐RESOLUTION X‐RAY POWDER DIFFRACTION AND CONVENTIONAL SPECTROSCOPY – CHROMATOGRAPHY

The employment of synchrotron techniques complemented by conventional laboratory systems has allowed us to deepen and improve our knowledge of Roman wall painting procedures. The palette identified in wall paintings from Pompeii and Herculaneum from the second century bc includes goethite, hematite, cinnabar, glauconite, Egyptian blue, and other components such as calcite and aragonite. Proof of the use of organic binders is provided by FTIR and PY–GC/MS. Therefore, the possibility of the use of ‘a secco’ techniques cannot be ruled out. Pigments in wall paintings are usually found in small percentages and conventional X‐ray diffractometers do not detect them. Synchrotron radiation – high‐resolution X‐ray powder diffraction has allowed identification with only a few micrograms of sample.

Effect of plant-derived organic binders on fracture toughness and fatigue of kaolin-based refractories

The fracture properties of kaolin-based refractories prepared using plant-derived binders from okra and “mrenda” have been investigated and compared. It was observed that the MOR of fired samples improved from 37.5 ± 0.1 MPa (for binder-free samples) to 69.6 ± 0.1 MPa, and to 120.0 ± 0.1 MPa for okra- and ‘mrenda’-plasticized samples, respectively, while the fracture toughness increased from 3.9 ± 0.1 MPa (for binder-free samples) to 5.6 ± 0.1 and 5.7 ± 0.1 MPa for okra and ‘mrenda’-plasticized samples, respectively. It is concluded that the use of organic binders enhances the reliability and service life of kaolin refractories used in thermally fluctuating environments.