Temperature-Programmed Thermogravimetr

Differential thermal analysis (DTA) is a technique in which the temperature difference between the sample tested and a reference material is measured while both are subjected to the controlled temperature program. Differential scanning calorimetry (DSC) is a technique in which the heat flow difference between the sample and reference material is monitored while both are subjected to the controlled temperature program. Thermogravimetric analysis (TGA) is a technique in which the weight of a sample is monitored during the controlled temperature program. 

For this purpose, all three catalyst supports were initially synthesized by a chemical vapor deposition (CVD) process and thereafter, using a wet impregnation method, loaded with cobalt as the active component for FTS. The as-synthesized Co/nanocatalysts were then characterized by applying electron microscopic analysis as well as temperature-programmed desorption, chemi- and physisorption measurements, thermogravimetric analysis, and inductively coupled plasma... 

By definition [26,27], thermogravimetric analysis is a technique in which the mass of a substance is measured as a function of time or temperature while the substance is subjected to a controlled temperature program. Because mass is a fundamental attribute of a material, any mass change is more likely to be associated with a chemical change, which may, in turn, reflect a compositional change. 

Thermal analysis is a group of techniques in which a physical property of a substance is measured as a function of temperature when the sample is subjected to a controlled temperature program. Single techniques, such as thermogravimetry (TG), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), dielectric thermal analysis, etc., provide important information on the thermal behaviour of materials. However, for polymer characterisation, for instance in case of degradation, further analysis is required, particularly because all of the techniques listed above mainly describe materials only from a physical point of view. A hyphenated thermal analyser is a powerful tool to yield the much-needed additional chemical information. In this paper we will concentrate on simultaneous thermogravimetric techniques. 

L. Ballice and R. Reimerta, Classification of volatile products from the temperature-programmed pyrolysis of polypropylene (PP), atactic-polypropylene (APP) and thermogravimetrically derived kinetics of pyrolysis. Chem. Eng. Process., 41(4), 289-296 (2002). 

Thermogravimetric analyses (TGA) were carried out with a Perkin-Elmer TGS-2 analyzer at a nitrogen flow rate of 50 cmmin. The temperature program for the analysis was 50 °C for 10 min followed by an increase of 5 °C/min to 600 °C. 

The precursor and the calcined catalyst were characterized by various techniques such as nitrogen adsorption, mercury porosimetry, X-ray diffraction (XRD), atomic emission spectrometry by inductively coupled plasma (ICP), thermogravimetric analysis, and temperature-programmed reduction (TPR). More details about the catalyst preparation and characterization can be found in a previous work (22). 

Thermogravimetric studies were carried out on a Setaram SF 85 balance under air flow (70 cm3/min) with a temperature program in the range from 25 to 800°C (heating rate 5°C/min ) including a plateau at 200°C for 30 min. 

The catalysts were characterized by N2 adsorption-desorption isotherms, thermogravimetric analysis (TGA), temperature-programmed desorption of ammonia (NH3-TPD), X-ray diffraction (XRD), Raman spectroscopy, in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), and X-ray photoelectron spectroscopy (XPS). The procedures and experimental conditions have been detailed elsewhere [9]. 

Air flow temperature programmed oxidation tests were performed on carbon materials alone, on carbon-powder catalyst mixtures and on carbon-filter mixtures. These latter were obtained by pounding in a mortar a piece of a carbon covered filter. Such tests were carried out with catalysed and uncatalysed filters using a thermogravimetric analyser (Netzsch TA 209). 

We have examined temperatured-programmed desorption (TPD) and thermogravimetric analysis (TGA) of isopropyiamine on a series of Si-, Co-, and Mg-substituted AIPO-5 samples. The TPD-TGA results on the substituted samples show ammonia and propene desorbing in a well-defined feature between 575 and 650K, a feature not observed on pure AIPO-5. The results suggest that TPD-TGA measurements of isopropyiamine may be useful in determining the framework concentrations and acid site densities for SAPO-5, CoAPO-5, and MAPO-5. 

Temperature programmed reduction (TPR), temperature programmed Ar heating (TPAr) and extent of reduction experiments were all performed in a Perkin Elmer thermogravimetric analyzer (TGA) Model TGA 7 described elsewhere [22]. H2 chemisorption measurements were eonducted using a flow chemisorption method and apparatus described by Jones and Bartholomew [24]. Activity measurements and high-pressure steam treatments were conducted in a fixed-bed microreactor described elsewhere [22]. A Micromeritics Gemini 2360 surface analyzer was used to measure N2 adsorption at liquid N2 temperature for BET surface area measurements. A Micromeritics Tri-Star 3000 analyzer with N2 adsorption was used to obtain the pore size distribution. 

TABLE 2-4. Aging-m-air of the rare earth sesquioxides. Quantitative data as determined from thermogravimetric analysis (TG) or temperature programmed descomposition (TPD). 

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