Thermogravimetric Analysis TG

Results of Carbon Nanomaterial Catalyst Characterization ICP, Chemisorption, Physisorption, Thermogravimetric Analysis (TG)... 

Major instrumentation involved with the generation of thermal property behavior of materials includes thermogravimetric analysis (TG, TGA), DSC, differential thermal analysis (DTA), torsional braid analysis (TBA), thermomechanical analysis (TMA), thermogravimetric-mass spectrometry (TG-MS) analysis, and pyrolysis gas chromatography (PGQ. Most of these analysis techniques measure the polymer response as a function of time, atmosphere, and temperature. 

Powdering, or grinding, of samples is a simple preparation method required in a number of spectrometric and spectroscopic techniques, such as x-ray diffraction (XRD), nuclear magnetic resonance (NMR), differential thermal analysis (DTA), thermogravimetric analysis (TG), or ATR-FTIR spectroscopy. Control of the particle size during grinding must be taken into account in attempting to obtain reliable results. 

Thermogravimetric analysis (TG) under oxidizing atmosphere reveals a high-temperature exothermic weight loss of 1.5 wt.% for the TEA sample, compared to 6.6 and 9.3 wt.% for TPA and TBA nanoslabs, respectively. From IR and TG it is concluded that nanoslabs are formed in presence of TEA, but the lower TEA content and the lower intensity of the double five-ring vibration indicate that the solid contains also less structured silica. 

This monograph provides an introduction to scanning ther-moanalytical techniques such as differential thermal analysis (DTA), differential scanning calorimetry (DSC), dilatometry, and thermogravimetric analysis (TG). Elevated temperature pyrometry, as well as thermal conductivity/diffusivity and glass viscosity measurement techniques, described in later chapters, round out the topics related to thermal analysis. Ceramic materials are used predominantly as examples, yet the principles developed should be general to all materials. 

Thermogravimetric Analysis (TG). TG involves weighing a sample while it is exposed to heat. The chief use of this technique has been to study the thermal decomposition of polymeric materials and to accumulate kinetic information about such decomposition. A sample is suspended on a sensitive balance that measures the weight (Figure 1) as it is exposed to a furnace. Air, nitrogen, or another gas flows around the sample to remove the pyrolysis or combustion prod-... 

Determination of the optimal heat treatment temperature in the reactor is done by differential thermal analysis (DTA) and thermogravimetric analysis (TG) it appears (Fig. 2) that in our experimental procedure, for all the studied granulometries (<25 to 250 gm), a specimen fired at 398 K for 3 h contains no mote gypsum, and a specimen fired at 423 K still contains almost only hemihydrate. Above this temperature anhydrite III appears. The very small amount of anhydrite 111 contained in a specimen fired at 423 K is different from a gypsum variety, but quite stable and characteristic for a variety of gypsum (Fig. 6) fZ]. 

Treated wood was divided into 5 layers from the top to the bottom symmetrically. The contents of nitrogen and phosphorus of each layer were measured by Kelder s method and spectrophotometric determination. Thermogravimetric analysis (TG) and differential thermal analysis (DTA) were performed over the temperature range room temperature- 600 T in an air of lOOml/min., using a heating rate of 10 °C/min. 

Infrared spectra (IR) were taken on a Nicolet 7199 FT-IR. Thermal analyses were obtained on a DuPont 1090 thermal analyzer. Thermogravimetric analysis (TG) and differential scanning calorimetry (DSC) were performed at lO C/min. heating rates under N2. Reduced viscosity measurements (4) were made at 40-C in OC Ubbelohde viscometers. Values reported are the average of at least two measurements, which were within 0.2% of each other. Reduced viscosity is defined as follows ... 

Thermogravimetric Analysis. Thermogravimetric analysis (TG and DTG) under nitrogen atmosphere was performed for aspen wood and the 16 partially converted wood residues. The TG and DTG curves are reproduced in Figure 5 for untreated wood and for 4 selected representative SCE residues. 

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

Scanning electron microscopy (SEM) Thermogravimetric analysis (TG) Transmission electron microscopy (TEM)... 

BH2 NH2-)n oligomers with n>5 have been studied by thermogravimetric analysis (TG) and differential scanning calorimetry (DSC) [30], as well as by mass spectrometry and X-ray photoelectron spectrometry. The results have been interpreted in terms of a large cyclic structure of poly(aminoborane) [31]. 

Fig. 15. Thermogravimetric analysis (TG solid line) and differential thermal analysis (DTA dotted line) of ODS-PPV in air. Reprinted with permission from L.-H. Wang et al., Synth. Met. 105, 85 (1999). Copyright 1999, Elsevier Science Ltd., Oxford.

An understanding of the complex physico-chemical phenomena associated with the formation and behavior of cementitious compounds is facilitated through the application of many different types of investigative methods. Techniques such as NMR, XRD, neutron activation analysis, atomic absorption spectroscopy, IR/UV spectroscopy, electron microscopy, surface area techniques, pore characterization, zeta potential, vis-cometry, thermal analysis, etc., have been used with some success. Of the thermal analysis techniques the Differential Thermal Analysis (DTA), Thermogravimetric Analysis (TG), Differential Scanning Calorimetry (DSC), and Conduction Calorimetric methods are more popularly used than others. They are more adaptable, easier to use, and yield important results in a short span of time. In this chapter the application of these techniques will be highlighted and some of the work reported utilizing other related methods will also be mentioned with typical examples. 

In thermogravimetric analysis (TG), the weight changes are determined as the sample is heated at a uniform rate. It differs from the semistatic or static method in which the sample is held at a constant temperature for a required period of time. In concrete investigations, TG is commonly used with DTA to follow the hydration reactions. The first derivative of change of mass (DTG) can also be used for identification purposes as it yields sharper peaks. TG cannot detect crystalline transitions as they do not involve weight losses. 

Polymer characterisation, stabilisation and degradation are very widely studied by Thermal Analysis (TA). Single techniques, such as thermogravimetric analysis (TG), differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), and dielectric thermal analysis (DETA) provide important information on the thermal behaviour of materials. However, to obtain a more complete profile of, say, polymer degradation gas analysis is required, particularly since all of the techniques listed give mainly physical information on the behaviour of materials. 

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