Thermal gravimetric analysis determinations

Determination of the thermal decomposition temperature by thermal gravimetric analysis (tga) defines the upper limits of processing. The tga for cellulose triacetate is shown in Figure 11. Comparing the melt temperature (289°C) from the dsc in Figure 10 to the onset of decomposition in Figure 11 defines the processing temperature window at which the material can successfully be melt extmded or blended. 

Thermal gravimetric analysis (TG) of mordenltes used for the reaction was conducted by Mettler Model TG-50. Amount of deposited coke was determined from weight loss between 400° and 700°C. 

Thermal stability of the vinyl ferrocene and ferrocene containing polymers plus unmodified polymer and neat ferrocene controls was determined by thermal gravimetric analysis at a heating rate of 10 /mln. The results are depicted in Figure 4. Apparently vinyl ferrocene imparts greater thermal stability to the BA/S/MAA polymer than the ferrocene additive. In fact, 1% vinyl ferrocene allows about a 50 C additional rise in temperature before decomposition relative to the unmodified polymer. Curiously, a substantial exotherm is present at 400 - 450 C (bump on curve) for the vinyl ferrocene modified polymers, but does not appear for the ferrocene modified polymers. 

Conversion of the as-deposited film into the crystalline state has been carried out by a variety of methods. The most typical approach is a two-step heat treatment process involving separate low-temperature pyrolysis ( 300 to 350°C) and high-temperature ( 550 to 750°C) crystallization anneals. The times and temperatures utilized depend upon precursor chemistry, film composition, and layer thickness. At the laboratory scale, the pyrolysis step is most often carried out by simply placing the film on a hot plate that has been preset to the desired temperature. Nearly always, pyrolysis conditions are chosen based on the thermal decomposition behavior of powders derived from the same solution chemistry. Thermal gravimetric analysis (TGA) is normally employed for these studies, and while this approach seems less than ideal, it has proved reasonably effective. A few investigators have studied organic pyrolysis in thin films by Fourier transform infrared spectroscopy (FTIR) using reflectance techniques. - This approach allows for an in situ determination of film pyrolysis behavior. 

Thermal gravimetric analysis (TGA) is undoubtedly the most widely used method of moisture content determination. The sensitivity and sophistication of TGA instruments ranges from the classical moisture balance (LOD) to specially designed microbalances enclosed in chambers that may be evacuated. Microprocessor control of the temperature increase has led to more reproducible and discriminating information. 

HPLC and GC analyses are two commonly used methods for determining the levels of impurities and residual solvent in the cake. Thermal gravimetric analysis is another very powerful tool. It detects not only the level of residual solvent, but also the temperature at which the solvent evaporates. If the cake weight loss due to solvent evaporation occurs at the melting point of the solid, this is a clear indication that solvent is trapped within the cake. 

There are several nonspecific methods available that can determine the total amount of solvent(s) in a sample. Loss on drying (LOD) determines the amount of volatile components that are released from a sample under specific temperature and/or vacuum conditions. Thermal gravimetric analysis (TGA) measures the loss of volatile components from a sample over a temperature gradient. The advantage of these methods is that they give an estimate of the volatile component content of a sample relatively quickly. The disadvantages of these methods are that they do not speciate and cannot account for volatile components that are trapped in the lattice structure of the compound. By accepting the limitations of these methods, a total solvent amount can be... 

Another simple identification determination of a drug substance is the melting point. A more sophisticated technique is differential scanning calorimetry (Fig. 1). The melting characteristic may be used for identification and is especially suitable for a polymorphic system. The existence of one or more polymorph forms can be identified. For the identification of hydrates or solvates, thermal gravimetric analysis (TGA) is used (Fig. 2). 

In this chapter we investigate and discuss the thermal, optical, electrical properties of the oligothiophene derivatives by means of differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), and UV-Vis spectroscopy. The thin films of these compounds produced by solution cast and vacuum deposition methods are characterised by AFM measurements in contact and non-contact mode, and by X-ray diffraction. Finally, an ultra-thin OFET is built, and the transistor characteristics are determined. 

In summary, the yield of volatile oil was larger for nahcolite than for trona. Thermal gravimetric analysis of the acid insoluble fractions of the mineral yielded good results comparable with the determination of volatile oils by direct heating and weighing. 

Thermal Analysis. Thermal and related properties of polymers can be determined by various procedures including thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), differential thermal analysis (DTA), torsional braid analysis (TBA), thermal mechanical analysis (TMA), and pyrolysis gas chromatography (PGC). 

Copolymer Characterization. Copolymer compositions were determined by elemental analysis and thermal gravimetric analysis. A Perkin-Elmer TGS-2 ther-mogravimetric analyzer, programmed from ambient to 800 C in N2 and air, was used. Spectroscopic analysis of the copolymers was not as useful as elemental analysis and thermal gravimetric analysis measurements for analyzing these copolymers. Viscometric measurements were made in a solution of water and NaCl with a Contraves low-shear viscometer. 

The caloriEc capacity and the energies of intetBctions between molecules and adsorbent are determined using a thermal gravimetric analysis coupled with differential scanning calorimetry (TGA/DSC) [78]. 

TGA— Thermal gravimetric analysis, a test method by means of heating and determining loss of weight. 

X-ray powder diffraction patterns were obtained by using a Philips PW 1729 diffraction automated with an ADP system. Cu Ka operated at 40 Kv and 30 ma was the x-ray source. Samples were scanned from 20 = 3 to 70 Thermal gravimetric analysis (TGA) was done by using a Du Pont 9900 thermal analysis system. IR spectroscopy was performed on a Bomem DA 3.02 FT-IR spectrometer. B, Al, and Mg were determined by ICP spectroscopy with the solutions obtained by dissolving the sample in 6N HCl. 

Quantitation provides the highest accuracy level achievable by CaCOs methods. The digestion of calcium carbonate can be determined in four different ways (1) digestion with acid (2) thermal gravimetric analysis (TGA at 105°C, 450°C, 550°C, and 1000°C... 

The mechanical, thermal, and dielectric properties of sisal fiber have been studied in detail. X-ray diffraction, Infrared Spectroscopy, Thermal Gravimetric Analysis, Scanning Electron Microscopy, Differential Scanning Calorimetry, Dynamic Mechanical Analysis etc., have been used to determine the characteristics of sisal fiber and provide theoretical support for processing and application of the fiber. 

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