Thermogravimetric analysis

About: Thermogravimetric analysis is a research topic. Over the lifetime, 37248 publications have been published within this topic receiving 862144 citations. The topic is also known as: thermal gravimetric analysis & TGA.

Low-temperature synthesized aluminosilicate glasses. Part II Rheological transformations during low-temperature cure and high-temperature properties of a model compound

Abstract: The reaction below 100 °C of a dehydroxylated clay (metakaolinite) suspended in an alkaline sodium silicate solution leads to an amorphous aluminosilicate, called low-temperature inorganic polymer glass (LTIPG or IPG). Some rheological transformations during the isothermal hardening process are followed with dynamic mechanical analysis (DMA) and compared with differential scanning calorimetry (DSC) and modulated differential scanning calorimetry (MDSC). It can be concluded that the change in storage modulus (DMA) during the formation of the inorganic network can be characterized quantitatively with the evolution of the heat capacity (MDSC), and that the reaction rate is not decreased by the vitrification process. During the first heating after polymerization up to 1000°C, the material shrinks due to the evaporation of residual water from the reaction mixture as illustrated by thermogravimetric analysis (TGA) and thermomechanical analysis (TMA). The low-temperature synthesized inorganic polymer glass is thermomechanically stable up to a temperature of at least 650°C. In that temperature zone, the glass transition can be detected with TMA and DMA.

Structural and Textural Properties of Pyrolytic Carbon Formed within a Microporous Zeolite Template

Abstract: A new class of pyrolytic carbon materials has been prepared by chemical vapor infiltration of a microporous zeolite powder followed by removal of the zeolitic substrate. A wide-pore Y zeolite was used as the substrate for the pyrolytic carbon, and propylene was used as the carbon precursor. The structure and porous texture of the resulting carbons were examined by X-ray diffraction, scanning and transmission electron microscopy, and by adsorption of N2 at 77 K and CO2 at 273 K. Carbon reactivity studies were performed by both nonisothermal and isothermal thermogravimetric analysis. Under the present conditions of chemical vapor infiltration (800−850 °C, 2.5 vol % C3H6, 1 atm of N2), high-surface-area microporous carbons, with wide microporosity, well-developed mesoporosity and high adsorption capacity were obtained. The carbon yield and the apparent surface area of the carbon increased with increasing propylene pyrolysis temperature. The morphology of the carbons was very similar to that of the zeolite te...

Mechanism and Kinetics of the Decomposition of Solids by a Thermogravimetric Method

Abstract: According to Doyle, the thermogravimetric curve of a decomposition reaction can be expressed by the equation log g(α)–log p(x) = B. The variable x depends on the temperature Tα, at which the fraction of the initial compound decomposed is α. Both g(α) and p(x) depend on temperature; however, B is independent of temperature. The trial-and-error method allows, for a given thermogravimetric curve, the determination of the g(α) and p(x) functions fitting the equation and thus an estimation of the probable mechanism of the reaction and of other kinetic parameters (activation energy and frequency factor). To facilitate the analysis of experimental data, a table of log g(α) values for various decomposition mechanisms and a plot of-log p(x) vs T for various activation energies are presented. The use of the table and the diagram is described.