Showing papers on "Thermogravimetry published in 1984"
TL;DR: In this paper, the electrical properties of the solid solutions between stabilized zirconia and ceria, (0.9-y)ZrO/sub 2/-yCeO/ sub 2/-0.1y, with 0 less than or equal to y less than and equal to 0.9, were investigated, between 1273 and 1673 K.
Abstract: The electrical properties of the solid solutions between stabilized zirconia and ceria, (0.9-y)ZrO/sub 2/-yCeO/sub 2/-0.1Y/sub 2/O/sub 3/ with 0 less than or equal to y less than or equal to 0.9, have been investigated, between 1273 and 1673 K, in a large range of oxygen partial pressures. The total electrical conductivity and the concentrations of the various charge carriers, determined through thermogravimetry and measurement of magnetic susceptibility at high temperature as a function of oxygen partial pressure, makes it possible to develop a model accounting for the transport properties as a function of temperature and oxygen partial pressure. On the basis of the present results, the materials in question appear to be suitable as membranes semipermeable to oxygen.
122 citations
TL;DR: In this paper, the thermal decomposition of sixteen metal sulfates was studied by thermogravimetry at heating rates of 2 and 5°C min −1 in flowing air and high-purity nitrogen.
101 citations
TL;DR: In this article, a detailed investigation of the thermal characteristics of six Kentucky bituminous coals undergoing pyrolysis in an inert atmosphere at three different heating rates was made by differential scanning calorimetry.
73 citations
01 Apr 1984
TL;DR: Chalcedony from Brazilian agates, has been investigated by using transmission-electron microscopy, X-ray-diffraction, thermogravimetry and optical techniques as mentioned in this paper.
Abstract: Chalcedony from Brazilian agates, has been investigated by using transmission-electron microscopy, X-ray-diffraction, thermogravimetry and optical techniques.
64 citations
TL;DR: The ratio of interlamellarly fixed water and bulk water, which may be determined easily by means of thermogravimetry, is found to be an important quality criterion for these O/W creams.
Abstract: O/W creams with crystalline gel structures (Water Containing Hydrophilic Ointment DAB 8, Non-ionic Hydrophilic Ointment DAC and a stearate cream) were investigated by means of small angle X-ray diffraction, differential scanning calorimetry, thermogravimetry and freeze fracture technique in combination with Transmission Electron Microscopy (TEM). It was found that these bases are building up two different colloidal gel structures, a hydrophilic gel phase and a lipophilic gel phase, each of them forming a coherent network. The hydrophilic gel phase is characterized by an interlamellar water layer; this interlamellarly fixed water is in a dynamic equilibrium with the bulk water phase. The lipophilic gel phase immobilizes mainly the inner (dispersed) phase. So the O/W creams presented here are supposed to be four-phase systems. The ratio of interlamellarly fixed water and bulk water, which may be determined easily by means of thermogravimetry, is found to be an important quality criterion for these O/W creams. The desired properties of water release of such a cream may be chosen by shifting the ratio of interlamellarly fixed water and bulk water.
57 citations
TL;DR: Using the derivative thermogravimetric technique, an investigation was made of the pyrolysis and oxidation of some heavy fuel oils and their separate paraffinic, aromatic, polar and asphaltene fractions as mentioned in this paper.
57 citations
TL;DR: Cristallisation isotherme a partir de l'etat fondu et etude par analyse thermique, diffractometrie RX et microscopie electronique.
Abstract: Cristallisation isotherme a partir de l'etat fondu et etude par analyse thermique, diffractometrie RX et microscopie electronique. Etude d'echantillons prepares en emulsion, en masse, par dechloruration ou par debromuration
57 citations
TL;DR: In this article, a linear relationship between procedural activation energy and heat of reaction is developed, which is typical of elementary reactions of atoms and small radicals, and the effects of alkali metal salts on the decomposition of coal under three gas atmospheres (N,. CO, and air) are investigated.
50 citations
DSM1
TL;DR: In this article, a detailed overview of the possibilities thermal analysis and in particular thermogravimetry has in studying low-temperature oxidation of coal is given, along with procedures with which representative samples of coal can be obtained.
42 citations
TL;DR: Two kinds of samples of cryptomelane: synthetic single crystals of K 133 Mn 8 O 16 (A) and (K,H 3 O) x Mn 8O 16 powder prepared by aqueous chemistry (B) were studied by thermogravimetry, magnetic, and electrical (dc and ac) measurements as discussed by the authors.
TL;DR: In this article, the work done on thermal studies of metal dithiocarbamato complexes during the period 1969-1982 is given. But the work in this paper is restricted to the case of metal DithiOCBAMato complexes.
TL;DR: In this article, a thermogravimetry-evolved gas analysis (TG-EGA) method has been developed for the determination of the AgO, Ag/sub 2 O, Ag, and Ag O content of silver oxide cathodes.
Abstract: A new, rapid, and precise thermogravimetry-evolved gas analysis (TG-EGA) method has been developed for the determination of the AgO, Ag/sub 2/O, Ag, and Ag/sub 2/CO/sub 3/ content of silver oxide cathodes. Cathode samples were analyzed by the present method and by the commonly used wet chemical method. The analysis is being used to study the rates of change in chemical composition during storage of cathodes prepared by various manufacturers. These results can be used to correlate the compositional changes with degradation in battery performance.
TL;DR: The graphite oxidation products were obtained by cold oxidation at 0°C of graphite in liquid medium and were dehydrated over P2O5 and characterized by chemical analysis and X-ray diffraction as discussed by the authors.
TL;DR: Application de l'analyse thermique differentielle de la calorimetrie differentialle, de la thermogravimetrie, de the thermodilatometrie, of l'analysis thermomecanique et de la theromecanometrie dynamique.
TL;DR: A simplified thermogravimetry/gas chromatography/mass spectrometry (TG/GC/MS) system has been developed which completely eliminates the off-line trapping and devolatilization step and the associated sample transfer problems as mentioned in this paper.
Abstract: A simplified thermogravimetry/gas chromatography/mass spectrometry (TG/GC/MS) system has been developed which completely eliminates the off-line trapping and devolatilization step and the associated sample transfer problems. There are no valves or transfer lines between the TGA furnace and the GC. The gaseous products generated in the TGA are taken from the immediate vicinity of the sample in the furnace and are cryogenically condensed on the front end of a wall-coated open tubular fused silica capillary chromatographic column. This minimizes undesired gas-phase pyrolysis and/or wall reactions in the furnace environment and results in a condensed off-gas sample which is already prepared for chromatographic separation. In addition to the above advantages in sampling the gaseous materials from the TGA furnace, the fused silica capillary column also provides other benefits. It is well known that glass capillary columns give better separations, shorter analysis times, and better sensitivity and are more inert than conventional packed GC columns. The use of these columns also enables one to change from the TG/MS to the TG/GC/MS configuration in a matter of minutes so that both kinds of data may be acquired to better elucidate the nature of thermally induced reactions. 6 references, 9 figures, 2 tables.
TL;DR: In this article, the swelling of a perfluorosulfonated membrane (Nafion) was studied using different thermal analysis techniques coupled with thermogravimetry, and it appeared clearly that water molecules are distributed in small droplets around the sulfonate dipoles.
TL;DR: In this paper, a thermogravimetry-mass spectrometry study of the decompositional behavior of binary transition metal carbonyls was carried out, showing that the actual decomposition may be much more complex than successive CO stripping, and in several instances relatively stable intermediates are formed.
TL;DR: In this paper, the thermal decomposition of strontium nitrate was studied by thermogravimetry and the reaction order, activation energy, frequency factor and entropy of activation were computed by means of the Coats-Redfern, Freeman-Carroll and Horowitz-Metzger methods.
TL;DR: In this paper, the liaisons anhydride plus intramoleculaires qu'intermolecularity are formed at 25 and 300°C, and at 200°C they form at least anhydrous liaisons.
Abstract: Etude entre 25 et 300°C. A 200°C il se forme des liaisons anhydride plus intramoleculaires qu'intermoleculaires
TL;DR: In this article, the electrical properties of ceria doped with yttria (10 mol%) were investigated between 1273 and 1673 K for a large range of oxygen partial pressure.
TL;DR: In this article, it was shown that Urea is unsuitable for latent heat-thermal energy storage because of its low thermal stability, though the latent heat and the material cost of urea are superior to those of polyethylene.
TL;DR: In this paper, the curing behavior of 4,4′-(bismaleimido)diphenyl ether (BE) in the presence of diamines containing amide groups in the back-bone was studied by differential scanning calorimetry.
TL;DR: In this article, a series of copolymers with dimethylsiloxane and poly(tetramethyl-p-silphenylene siloxane) were characterized by means of ir and nmr spectroscopy and number average molecular weight measurements.
TL;DR: Etude par thermogravimetrie et mesures du changement de sa conductivite electronique par chauffage dans largor, loxygene et l'air de 20 a 100°C as discussed by the authors.
Abstract: Etude par thermogravimetrie et mesures du changement de sa conductivite electronique par chauffage dans l'argor, l'oxygene et l'air de 20 a 100°C
TL;DR: Two silicon-containing acid dichlorides, bis(4-chlorocarbonylphenyl)dimethylsilane and bis(3-phenylene diamine), were synthesized and reacted with 12 structurally different high molecular weight aromatic polyamides, and the thermal behavior of these aramids was studied by dynamic thermogravimetry as discussed by the authors.
Abstract: Two silicon-containing acid dichlorides, bis(4-chlorocarbonylphenyl)dimethylsilane and bis(4-chlorocarbonylphenyl)diphenylsilane, were synthesized and reacted with 1,3-phenylene diamine, 1,4-phenylene diamine, 4,4′-diaminodiphenyl, 4,4′-diaminodiphenyl methane 4,4′-diaminodiphenyl ether, and 4,4′-diaminodiphenyl sulfone in the preparation of 12 structurally different high molecular weight aromatic polyamides. A low-temperature interfacial polycondensation technique was used. Most of the polyamides formed tough, transparent, flexible films and were characterized by solubility, solution viscosity, infrared spectroscopy (IR), and glass transition temperature (Tg). The thermal behavior of these aramids was studied by dynamic thermogravimetry. The effect of diamine and acid dichloride structure on the aramids properties is also discussed.
01 Jan 1984
TL;DR: In this article, the effect of water content on the glass transition temperature of polyacrylamide polymers has been studied by means of Differential Scanning Calorimetry (DSC), Thermogravimetry, Thermomechanical Analysis (TMA), and Simultaneous Thermophravimetric Mass Spectrometry (TG-MS).
Abstract: The effect of a plasticizer on the glass transition temperature (Tg) of an amorphous polymer is well documented. However, similar behavior of water in synthetic polymers has only recently been recognized. The effect of water content (or thermal history) on the Tg’s of acrylamide polymers has been studied by means of Differential Scanning Calorimetry (DSC), Thermogravimetry (TG), Thermomechanical Analysis (TMA) and Simultaneous Thermogravimetry — Mass Spectrometry (TG-MS). Commercial samples of polyacrylamide and poly-(acrylamide-co-acrylic acid) from several sources were investigated and were found to contain measurable amounts of water. A pronounced plasticizing capability was detected for a relatively low concentration of water. A lowering of the glass transition temperature of the homopolymer by about 70°C was observed with a concentration of less than 8%. A similar effect was also observed for the β transition and a ratio of 0.66 was obtained for Tβ (°K)/ Tg (°K).
TL;DR: Amorphous samples of a new inorganic ion exchanger, cerium(IV) selenite have been prepared under varying conditions in this article, where the ion exchange capacity, chemical stability, IR, thermogravimetry and Kd values were investigated.
Abstract: Amorphous samples of a new inorganic ion exchanger, cerium(IV) selenite have been prepared under varying conditions. The material prepared by mixing 0.025M ceric sulfate and 0.025M sodium selenite in the ratio of 1∶1 was studied in detail for its ion-exchange capacity, chemical stability, IR, thermogravimetry and Kd values. Separations of metal ions have been performed on columns of this ion exchanger.
TL;DR: In this paper, a thermal analysis of urea and its decomposition product, biuret, was achieved by using differential scanning calorimetry (DSC) and derivative thermogravimetric (DTG).
TL;DR: In this paper, the thermal dehydration kinetics of crystalline powders of (COOH)2 · 2 H2O were examined by thermogravimetry both at constant and linearly increasing temperatures.
Abstract: The thermal dehydration kinetics of crystalline powders of (COOH)2 · 2 H2O was examined by thermogravimetry both at constant and linearly increasing temperatures. An Avrami-Erofeyev law is found to hold with a possibility that a phase-boundary controlled reaction proceeds simultaneously. This is supported by the particle size effect on the rate constant. The activation energyE for the dehydration is estimated as around 80 kJ mol−1. It is likely that the effects of particle size and temperature onE are compensated by those on the frequency factorA.