Redox potential of a glass mass when using off-grade raw materials

The redox conditions for glass making are investigated on a working glass-melting furnace using molding sand. Data obtained from instrumental measurements of the ROP of the glass mass and reasons for destabilization of the technological process are presented. __________ Translated from Steklo i Keramika, No. 6, pp. 6–8, June, 2007.     

Acid-Base Reactions Between Components in Sodium-Aluminoborosilicate Glasses

The effect of coordination groups of boron, aluminum, and silicon on acid-base properties and specifics of the variation in the redox state of copper in boron-containing melts are investigated. An approximate evaluation of acid-base properties of industrial glasses synthesized in an alkaline-aluminoborosilicate system is implemented.     

Color control and redox balance monitoring in container glass

Modern methods and systems for monitoring the redox balance in glass as a key parameter for stabilizing the glassmaking process and attaining reproducible prescribed functional properties of glass and glass articles are examined. It is shown that the value of the trichromatic characteristics — the dominant wavelength, purity, and brightness of the color — must be used to monitor the light protection function of glass. __________ Translated from Steklo i Keramika, No. 4, pp. 3–6, April, 2007.     

Heteropolysalt-supported heteropolyacids as a new class of acid-base and redox catalysts

Heteropolyacid catalysts of composition H_3+n PV _n Mo_12–n O₄₀ (n = 0,1,2,3) when supported on K₃PMo₁₂O₄₀ desplay new types of acid-base and redox properties and have enhanced thermal stability.     

Ce对玻璃光谱曲线及色度指标的影响

用CeO2及TiO2混合着色可以生产金黄色的玻璃,铈的用量及玻璃配合料氧化还原性都容易造成玻璃光学指标及色度指标的改变,使玻璃产生较大的色差。通过改变玻璃中铈的用量和氧化还原剂用量熔制玻璃样片,然后用CARY500分光光度计对玻璃样片进行光度及色度指标分析。结果表明:着色剂的用量、配合料的氧化还原性、萤石的添加量对玻璃的光学指标及色度指标都有较大影响。     

Experimental study of bubble formation in a glass-forming liquid doped with cerium oxide

This work aims to study the mechanisms of oxygen bubble formation coming from redox reaction of a polyvalent element incorporated in a glass melt. Borosilicate glass composition is selected for its use as a glass matrix for nuclear waste conditioning. Cerium is selected as a polyvalent element as it may be found in nuclear waste. The chosen material is characterized in terms of physical properties which influence bubble formation and growth. A postmortem optical microscope approach is used to observe bubbles in the investigated material after thermal treatment for varying temperatures (900°C-1100°C) and durations. To support the understanding of oxygen bubble formation, cerium speciation by X-ray absorption near-edge structure (XANES) and bubble gas composition are experimentally evaluated. In this article, we indicate how bubbles are formed in the investigated glass melt system. It is also demonstrated that the mechanisms that govern bubble evolution are fundamentally the same and that the plot's optimum points are strongly influenced by the temperature. These last statements are confirmed by considering some bubble features, such as bubble mean density and bubble mean diameter evolutions, and normalizing the experimental time using a characteristic residence time (t_η) obtaining thereafter a dimensionless time, which is a function of the glass melt properties obtained by the physical characterizations. The impact of temperature and time on bubble formation is described.     

Dynamics of the redox state of the melt in the continuous production of clear glass

The effect of a set of external factors on the redox equilibrium of iron and sulfur, changes in melt properties, and light transmission of clear sheet glass is investigated for continuous production of glass. A quantitative estimate of trends in the variations of the redox potential of glass melt is proposed. Practical measures improving the efficiency of a tank furnace by correcting the oxidation state of the melt are considered. __________ Translated from Steklo i Keramika, No. 8, pp. 5–9, August, 2006.     

Experimental and numerical investigations of an oxygen single-bubble shrinkage in a borosilicate glass-forming liquid doped with cerium oxide

The shrinkage of an oxygen single-bubble is investigated in a cerium-doped borosilicate glass melt at 1150°C. Nine glass samples are synthesized and investigated, utilizing three different amounts of Ce₂O₃ and three different redox ratios (Ce-(III)/Ce_total). Employing in-situ observation, the single-bubble behavior is recorded with a camera. For each glass melt, five experiments are performed with different initial bubble radii. The shrinkage rate () depends strongly on the cerium content as well as the redox ratio. Numerical calculations are also conducted to support the understanding of the bubble shrinkage mechanism in the given cases. The model adequately estimates the experimental data for several cases, and an explanation is proposed for the cases, in which it does not. Moreover, we demonstrate, physically and mathematically, the influence of the initial radius of the bubble on the mass transfer between the rising bubble and the melt. We confirm the utilization of the “modified Péclet number,” which is a dimensionless number that takes into consideration the influence of multivalent elements on mass transfer. Finally, we master the bubble shrinkage behavior by normalizing the experimental data employing a characteristic time for the mass transfer (τ).     

Preparation,characterization, and some physical properties of polypropylene/poly(methyl acrylate)‐grafted glass wool composites

Polypropylene/poly(methyl acrylate)‐grafted glass wool (PMA‐g‐GW) mixes were prepared. The polymerization process was carried out using potassium persulfate (PPS) and PPS/acetone sodium bisulfite (ASBS) as a redox‐pair initiation system at 60 and 70°C. The effect of using PPS or PPS/ASBS on the grafting percent and conversion percent reveals that the conversion percent values on using PPS as an initiator are higher than those of PPS/ASBS, while in the case of grafting, the inverse is true, that is, using PPS as an initiator gives grafting percent values lower than those that can be obtained using PPS/ASBS. The dielectric properties, thermal diffusivity, specific heat capacity, and thermal conductivity of PP loaded with modified glass wool as a function of different types and concentrations of initiators—used in the grafting polymerization process, namely, PPS and the redox initiating system—were also studied. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 723–732, 2003     

Solution‐processable and electroactive aromatic polyamides with 3,5‐bis(trifluoromethyl)triphenylamine moiety

New fluorine‐containing, triphenylamine‐based diamine and dicarboxylic acid monomers, namely 3,5‐bis(trifluoromethyl)‐4′,4″‐diaminotriphenylamine and 3,5‐bis(trifluoromethyl)‐4′,4″‐dicarboxytriphenylamine, were synthesized and polymerized with commercially available aromatic dicarboxylic acids and diamines, respectively, leading to two series of aromatic polyamides, 5a–h and 7a–e . Most of the polyamides were amorphous and readily soluble in many common organic solvents and could be solution‐cast into transparent, flexible and strong films with good mechanical properties. The polyamides had useful levels of thermal stability associated with high glass transition temperatures of 273–305 °C and 10% weight‐loss temperatures in excess of 500 °C. Cyclic voltammograms of films of polymers 5a–h on indium–tin oxide‐coated glass substrates exhibited reversible oxidation redox couples with E_1/2 around 1.15 V versus Ag/AgCl in tetrabutylammonium perchlorate/acetonitrile solution, accompanied by a color change from colorless neutral state to reddish brown oxidized state. The 7 series polymers displayed a higher oxidation potential and less electrochemical stability as compared to the 5 series analogues. © 2017 Society of Chemical Industry     

NOx storage/reduction catalysts based in cobalt/copper hydrotalcites

The use of materials based on hydrotalcites as NO_x storage/reduction (NSR) catalysts has been investigated, examining their activity at low temperature and their resistance to poisons such as H₂O and SO₂. The results obtained show that catalysts derived from Mg/Al hydrotalcites containing copper or cobalt is active at low temperatures, specially the samples containing 10 or 15% of Co. The addition of 1 wt% of transition metals with redox properties such as Pt, Pd, V and Ru to the hydrotalcite increases its activity because the combination of the redox properties of these metals and the acid-base properties of the hydrotalcite. The best results were obtained with the catalyst derived from a hydrotalcite with a molar ratio Co/Mg/Al = 15/60/25 and containing 1 wt% V. This material shows a higher activity, at low temperatures and in the presence of H₂O and SO₂, than a Pt–Ba/Al₂O₃ reference catalyst.     

Reversible redox behaviour of two electroactive polymethacrylates

Summary The radical melt polymerization of 2-[4-(6-methacryloyloxyhexa-1,6-diyloxy)phenylazo]-anthraquinone is described yielding the homopolymer p _m with the number average molecular weight (M _n ) of M _n =74kg/mol determined by gel permeation chromatography (GPC) using polystyrene (PS) calibration. The redox properties of a thin film of p _m were investigated by cyclic voltammetry. Two reversible redox waves were found at all applied sweep rates indicating two reversible electron (E) transfer processes of the anthraquinone units according the EE-mechanism. A thin film of the randomlike copolymethacrylate cp _r with the molar mass of M _n =73kg/mol was investigated, too. The sidegroups of cp _r are substituted by 77mol% with benzyl, by 22mol% with phenylazoanthraquinone and by 1mol% with COOH groups. The redox properties of cp _r depend on the timescale of the cyclovoltammetric experiment. At high sweep rates two reversible redox waves are observable corresponding to the EE-mechanism. At low sweep rates an additional reversible redox wave appears, which is essentially smaller than the other two. The third wave is explained to be a result of hydrogen bonding between the COOH groups and anthraquinone mono- and dianions. The most anthraquinone units are reduced according the EE-mechanism without hydrogen bonding due to statistical reasons. The reversible redox properties of p _m and cp _r are closely connected to their molar masses (M _n ≈75kg/mol), because both polymers have been previously obtained by radical solution polymerization yielding low molecular products with molar masses of M _n ≈10kg/mol. The low molecular polymers have shown an irreversible redox behaviour. Therefore, it could be demonstrated that the molar mass of an electroactive polymer significantly affects its redox properties. Received: 13 November 1998/Revised version: 30 March 1999/Accepted: 20 April 1999     

On the role of acidity in catalytic oxidation

The role of the catalyst surface acid-base properties on the heterogeneously-catalyzed oxidation reaction mechanisms is discussed. Acid-base properties depend on the covalent/ionic character of the metal-oxygen bonds and are involved in some steps of the oxidation reactions, such as the activation of the C---H hydrocarbon bonds, the step associated with the evolution of alkoxide species and the desorption/overoxidation of the partial oxidation products. Thus they participate with the cation redox properties in determining the selective/unselective catalyst behavior.     

亚磷酸镁制备初步研究

研究了酸碱中和法制备亚磷酸镁的反应条件,探究了亚磷酸与碳酸镁以不同配比进行反应时对所得产物的影响,采用X射线衍射（XRD）、电位滴定、氧化还原滴定等方法对制备的产物进行了表征。结果表明,当亚磷酸与碳酸镁物质的量比约为1.0时形成的是6水合亚磷酸镁;当亚磷酸与碳酸镁物质的量比约为2.0时则形成了酸式盐即0.33水合亚磷酸氢镁;当亚磷酸与碳酸镁物质的量比偏离1.0和2.0较远时,有形成非晶态物质的倾向。氧化还原滴定法测定亚磷酸与碳酸镁物质的量比为1.0所得产物时,以亚磷酸计质量分数为72.66%,折算成亚磷酸镁质量分数为92.43%;测定亚磷酸与碳酸镁物质的量比为2.0所得产物时,以亚磷酸计质量分数为84.79%,折算成亚磷酸氢镁质量分数为96.32%。电位滴定分析结果表明,亚磷酸镁盐滴定曲线有两个突跃,与亚磷酸的二元酸的性质吻合。     

浮法玻璃中铁的价态测试方法探讨

铁是无色透明玻璃中主要着色元素,而玻璃中铁价态变化,影响玻璃光学性能、热学性能.玻璃中铁价态变化反映玻璃液氧化还原状态,玻璃液氧化还原状态是硫酸盐澄清微泡是否析出重要原凶.本文通过对玻璃中铁的价态测试方法进行分析对比,探索浮法玻璃中铁的价态快速准确测试方法.     

Temperature influence on the physicochemical surface properties and adhesion behaviour of Enterococcus faecalis to glass and silicone

The interest in studies on the physicochemical surface properties of bacteria has increased because they are related to the causes of the initial adhesion of microorganisms to biomaterials and the subsequent biofilm formation on indwelling medical devices. The determination of physicochemical parameters such as hydrophobicity or surface tension is usually done at room temperature, not taking into account the real temperature at which bacteria cause infection inside the human body. In this work, the influence of the experimental temperature on the surface physicochemical characteristics and adhesion behaviour of Enterococcus faecalis ATCC29212 to glass and silicone has been studied. Water, formamide and diiodomethane contact angles on bacterial lawns changed when the experimental temperature was increased from 22°C to 37°C. Moreover, hydrophobicity, as determined by water contact angle, increases with temperature, in agreement with the higher and lower adhesion to silicone and glass, respectively, observed at 37°C, with respect to the results at 22°C. Also, when the formamide and diiodomethane contact angles are considered, the changes in the adhesion behaviour to glass and silicone are predicted by the sum of Lifshitz-van der Waals and acid-base interaction free energies if the measurement temperature is the same as the bacterial growth temperature, i.e. 37°C.     

Vaporization processes and thermodynamic properties of oxide systems at high temperatures: Experimental study and modeling

The thermodynamic properties and vaporization of glasses and melts in binary and multicomponent oxide systems are analyzed using high-temperature mass spectrometric data. The main regularities of vaporization processes are considered in the framework of the acid-base concept. The thermodynamic properties are calculated in terms of the generalized lattice theory of associated solutions.Original Russian Text Copyright © 2005 by Fizika i Khimiya Stekla, Stolyarova, Plotnikov.     

Direct electrodeposition of thin-layer (phenylene–carbazolylene) copolymers

Thin (phenylene–carbazolylene) copolymer films of controlled composition can be directly deposited onto solid cathodes such as indium tin oxide (ITO) glass or glassy carbon through a dehalogenative polycondensation of 4,4′-dibromobiphenyl and 3,6-dibromo-N-alkylcarbazole mixtures in the presence of an electrogenerated zero-valent nickel catalyst. The electrochemical and optical properties of the resulting thin films have been studied. The electrochemical behavior reveals two distinct electronic states that depend on the copolymer composition and structure. The first electronic state is characterized by either only one redox process, attributed to the presence of phenylene-disubstituted carbazolic units in the case of copolymers with the highest proportion of phenylene, or two successive redox processes, attributed to the occurrence of a radical cation and dication of carbazolic diades, in the case of copolymers with the lowest proportion of phenylene. The second electronic state shows in all cases a single redox system occurring at a higher potential than the first state and due to phenylene moieties in the copolymer. All the electrodeposited copolymer films were found to be reducible in the same manner as pure poly(p-phenylene). © 1994 John Wiley & Sons, Inc.     

NOTES ON DIAGNOSING CAUSES OF CORDS IN GLASS

The physical properties, e. g., refractivity, viscosity, and expansion coefficient, of cords generally differ from those of the mass of the glass. Methods are described for rapidly ascertaining the relative values of these properties. This information, together with a knowledge of the batch ingredients and possible impurities may afford n certain cases a means of determining the cause of the cords.     

Influence of interfacial interactions on the properties of PVC/cellulosic fiber composites

The surface properties at the interface between thermoplastic and cellulosic fibers strongly influence the mechanical properties of plastic/cellulosic fiber composites. This paper examines the role of surface acid-base properties of plasticized PVC and cellulosic fibers on the mechanical properties of the composites. The acid-base surface characteristics of cellulosic fibers were modified by treating the fibers with γ-aminopropyltriethoxysilane (A-1100), dichlorodiethylsilane, phthalic anhydride, and maleated polypropylene. The empirical acid (K_A) and base (K_D) characteristics (i.e., electron donor/acceptor abilities) of untreated and treated fibers, as well as plasticized PVC, were determined using inverse gas chromatography (IGC) technique. These parameters were used to yield information on the acid-base pair interactions that were correlated with the tensile and notched Izod impact properties of the composites. Acid-base pair interactions have been found to be a valuable parameter in the design of surface modification strategies intended to optimize the tensile strength of the composites. By tailoring the acid-base characteristics of cellulosic fibers and plasticized PVC, a composite with equal tensile strength and greater modulus than unfilled PVC was developed. However, the acid-base factors did not correlate with tensile modulus, the elongation at break, and the notched Izod impact property of PVC/newsprint fiber composites. Aminosilane has been observed to be a suitable adhesion promoter for PVC/wood composites improving significantly the tensile strength of the composites. Other treatments (dichlorodiethylsilane, phtalic anhydride, and maleated polypropylene) were found to be ineffective, giving similar strength compared to the composites with untreated cellulosic fibers. FTIR spectroscopy results suggested that aminosilane was effective because treated cellulosic fibers can react with PVC to form chemical bonds. The resulting bond between PVC and cellulosic fibers accounts for the effectiveness of aminosilane, when compared with other coupling agents.