Thermal gravimetric analysis contents

The crystals of halcinonide are not solvated with water, based on a total volatile content of 0.3% obtained by thermal gravimetric analysis, a correct elemental analysis, and a loss-on-drying value of 0.6% (of. section 4.1, Elemental and Inorganic Analyses). 

Thermal gravimetric analysis shows that the increase in phosphorus content results in char yield increases which are correlatable with the self-extinguishment time decreases. This led to the conclusion of phosphorus "rich" barrier shielding the surfaces as a mechanism of the flammability decrease. 

The degree of hydration of the products from these preparations and the water content given by analytical procedures depends upon the heat treatment (method and history) of the product. A sample subjected to TGA (thermal gravimetric analysis) looses water almost continually from room temperature until it becomes the completely anhydrous heteropolytungstate salt at about 400°C. On the other hand, these crystals lose some lattice water rapidly upon removal from the mother liquor and exposure to air even at room temperature. 

Fig. 15. Thermal gravimetric analysis in an air atmosphere of poly(siloxane imide)-seg-mented copolymers of various siloxane concentrations, indicating char yield proportional to siloxane content...

Several conventions will be followed in this article. Moisture contents are expressed on a dry weight basis. When necessary, the subscript 1 is used for water, and the subscript 2 for the other component in the adsorbent in the absence of a subscript, the property is to be attributed to water. Results of many routine tests conducted in my laboratory have been included here. Although the specific equipment used and all the experimental details are not provided, an effort has been made to include information that can substantially influence the results of the test (e.g., heating rate in thermal gravimetric analysis). These data should be taken as being representative of the substance tested and not necessarily as the results to be expected for a given lot of the substance examined with different instrumentation under different experimental conditions. 

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. 

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... 

Volatiles Content (a) Thermal Gravimetric Analysis (TGA) using a DuPont 990 system and 951 TGA unit sample size 10 mg temperature 115°C atmosphere nitrogen or vacuum (b) Oven drying ... 

The chemical polymerization of Py by CAN in PU solutions leads to the formation of PU/PPy composites. The composites were characterized by Fourier transform infrared spectrophotometry-attenuated total reflectance (FTIR-ATR], dynamic mechanical analysis (DMA], thermal gravimetric analysis (TGA], differential scanning calorimetry (DSC], X-ray photoelectron spectroscopy (XPS], and SEM measurements. The absorbances of the disordered H-bonded urethane carbonyl decrease with increasing Py concentration. The fraction of the hydrogen-bonded carbonyls is increased and the melting point increases with the increase of PPy content. These indicate the incorporation of PPy into PU may cause the complex due to the intermolecular interaction between the PPy and PU. SEM images of composite nanofibers show good distribution of the second component and the composite solution is proper to form conductive composite nanofibers. 

The thermal stabilities of these composites were determined by thermal gravimetric analysis. Figures 10.9 and 10.10 and Table 10.2 present the TGA and derivative of thermal thermogravimetric analysis (DTG) of epoxy composites with various DPPES-GNO and GNO contents, respectively, that were heated at a rate of 10 °C/min under N2. Tds is the temperature at which the weight loss of the sample reaches 5%. Figure 10.9 and Table 10.2 indicate that the values of DPPES-GNO nanocompo-... 

Thermogravimetry or thermal gravimetric analysis TG or TGA Mass change Decomposition temperature Oxidation temperature Volatilisation of moisture and plasticiser Moisture content... 

Thermal gravimetric analysis (TGA) indicated that amide-containing materials were stable at higher temperatures in contrast to carbamate and urea based polymers. This trend closely corresponds to that already observed for the corresponding monomers. The decomposition temperature of all polymers was almost independent of the PEG content. 

A report is presented on the diagnosis of the failure of a component made from a 33% glass-reinforced nylon 66 on the assembly line with the aid of DSC, thermal gravimetric analysis, which was utilised to determine filler content and type. X-ray fluorescence and IR spectroscopy. The analytical procedures employed indicated that failure of the component could be attributed to the presence of chlorine probably arising from contamination of the process by PVC. 

A historically important form of gravimetric analysis was combustion analysis, used to determine the carbon and hydrogen content of organic compounds burned in excess 02 (Figure 27-4). Instead of weighing combustion products, modem instruments use thermal conductivity, infrared absorption, or coulometiy (with electrochemically generated reagents) to measure the products. 

The crystal structure of as prepared samples was identified by using a powder X-ray diffractometer equipped with CuKa radiation (30kV, 20mA) and a monochromator. An infrared spectrometer was used for the chemical structure analysis. Chemical composition of samples was determined by EDX analysis. To determine the content of organic species in the composites, thermal gravimetric (TG) analysis was carried out at a heating rate of 10 °C/min in air. The BET surface area was determined by measuring N2 adsorption isotherms at 77 K. The microstructure of samples was observed by FE-SEM. Diffuse reflectance spectra were recorded with a UV-vis spectrometer. 

Table 5.4 Parameters of thermal analysis, PPy content determined by gravimetric analysis and electrical conductivity of pure components and composites. Reproduced from [62] with permission of Elsevier.

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