Thermal analytical methods

The structure of the catalysts was characterized by X-ray diffraction, IR-spectroscopy and transmission electron microscopy, their thermal stability was followed by thermal analytical method. The specific surface area and pore size distribution of the samples were determined by nitrogen adsorption isotherms. 

Thermal analytical methods are used to research raw materials and green as well as baked products. Clays can be identified and you can determine which physical and chemical process take place in the clay when the temperature is raised. 

Used widely in synthetic macromolecular and natural biopolymer fields to evaluate structural and thermodynamic properties of macromolecular materials, thermal analytical methods have been applied to assist in the characterization of natural organic matter (NOM). Originally applied to whole soils, early thermal studies focused on qualitative and quantitative examination of soil constituents. Information derived from such analyses included water, organic matter, and mineral contents (Matejka, 1922 Tan and Hajek, 1977), composition of organic matter (Tan and Clark, 1969), and type of minerals (Matejka, 1922 Hendricks and Alexander, 1940). Additional early studies applied thermal analyses in a focused effort for NOM characterization, including structure (Turner and Schnitzer, 1962 Ishiwata, 1969) and NOM-metal complexes (e.g., Schnitzer and Kodama, 1972 Jambu et al., 1975a,b Tan, 1978). Summaries of early thermal analytical methods for soils and humic substances may be found in Tan and Hajek (1977) and Schnitzer (1972), respectively, while more current reviews of thermal techniques are provided by Senesi and Lof-fredo (1999) and Barros et al. (2006). 

Thermal analysis is suitable for the study of the changes under heat, including the changes in mass and enthalpy (Smykatz-Kloss and Warne 1991 Liptay 1973). In addition, when the minerals are qualitatively or semiquantitatively known from x-ray diffraction studies, their quantity can be determined more precisely on the basis of characteristic thermal changes of the minerals. Thermal analytical methods give very useful information on the types of water in clay minerals and on the valency of the interlayer cation (Chapter 2, Section 2.1.2 Foldvari 1991 Foldvari et al. 1998). 

When analyzed using common thermal analytical methods [e.g., differential scanning calorimetry (DSC)], amorphous materials will exhibit an apparent second-order phase transition (the so-called glass transition temperature or Tg) in a temperature... 

Differential scanning calorimetry (DSC), X-ray diffraction (XRD), and infrared spectroscopy are the common techniques used in the characterization of the structure of the congealed solid. Thermal analytic methods, such as DSC and differential microcalorimetric analysis (DMA), are routinely used to determine the effect of solutes, solvents, and other additives on the thermomechanical properties of polymers such as glass transition temperature (Tg) and melting point. The X-ray diffraction method is used to detect the crystalline structure of solids. The infrared technique is powerful in detecting interactions, such as complexation, reaction, and hydrogen bonding, in both the solid and solution states. 

Polyethylene glycols (PEG) have been intensively characterized by thermal analytic methods. The melting points of PEG increase with the molecular weight and decreases with the content of water as a result of eutectic formation. " Corrigan studied the different DSC peaks of PEG Once folded chain crystals and extended chain crystals are present in PEG 6000, which results in two DSC peaks. In PEG of higher molecular mass, only folded chain crystals are present. Lower molecular mass PEG contain only extended chain crystals. Craig reviewed the thermal studies of PEG, including properties in aqueous solutions. " " ... 

The reaction of In(I) with an aqueous thiosulphate solution leads to 1028203 2(1120), 1028203 10-0H 2(H20), and 1028203 2InN03 2(H20). These compounds have been characterized by IR spectroscopy. X-ray diffraction, and by thermal analytical methods." A study of In/In(N03)3 disproportionation to InNOs has been carried out, and shows that the nitrate ion exhibits a much... 

Cu - and Fe -ion containing ZSM-5 zeolites woe prepared by conventional and solid-state ion-exchange methods described in ref [15]. The Si/Al ratio of parent Na-ZSM-5 was 40. The samples were characterized by X-ray diffiaction, IR spectroscopy, thermal analytical method and BET measuronent. Related data are shown in Table 1. 

Some reactions can be quite exothermic. Before running a reaction without solvent, it would be best to check the heat of reaction by thermal analytical methods. This will avoid runaway reactions. A thermoregulator should also be used to control the temperature. 

For the last twenty years much work has been done in the study of the thermal stability of lignocellulosic materials by thermal analytical methods. Since these materials are complex mixtures of organic polymers, thermogravimetric (TG) analysis causes a variety of chemical and physical changes depending on the nature of the sample and its treatment prior to analysis. These problems have been reviewed recently. ... 

Saffell, J.R., Matthiesen, A., McIntyre, R. et al. 1991. Comparing thermal stimulated current (TSC) with other thermal analytical methods to characterize the amorphous phase of polymers. Thermochim. Acta 192 243-264. 

The temperature behavior of crosslinked phenolics can be described by using difierent thermal analytical methods. DTA, DSC and DMA can be applied for analysis of transitions in crosslinked phenolics. TMA investigation of crosslinked phenolics gives the linear expansion coefficient and the glass transition temperature. TGA is used to study the thermal stability of the material and its decomposition. 

There are two thermal analytical methods for investigating the melting behavior, these being the static and dynamic methods. The dynamic method has the advantage of giving the results in a short time by increasing sample temperature, thou there is a drawback of less quantitative evaluation in the results compared with the static method which keeps the sample at a constant temperature. 

Thermal analytical methods, particularly DSC, " continue to be widely used to measure the thermodynamic parameters of crystallization and melting. Since an independent method of determining the equilibrium enthalpy of fusion, AHf (T) of totally crystalline polymer at the temperature of interest, T, is required to measure the degree of crystallinity, the techniques are used to obtain a qualitative measure of crystallinity. The application and limitations of the techniques have been discussed. "... 

Abstract Thermal analytical methods such as differential scanning calorimetry (DSC) have been successfully applied to neat petrodiesel and engine oils in the last 25 years. This chapter shows how DSC and P-DSC (pressurized DSC) techniques can be used to compare, characterize, and predict some properties of alternative non-petroleum fuels, such as cold flow behavior and oxidative stability. These two properties are extremely important with respect to the operability, transport, and long-term storage of biodiesel fuel. It is shown that the quantity of unsaturated fatty acids in the fuel composition has an important impact on both properties. In addition, it is shown that the impact of fuel additives on the oxidative stability or the cold flow behavior of biodiesel can be studied by means of DSC and P-DSC techniques. Thermomicroscopy can also be used to study the cold flow behavior of biodiesel, giving information on the size and the morphology of crystals formed at low temperature. 

Different standard methods are used to determine or predict the low temperature behavior of a fuel in terms of CP, CFPP and PP. The repeatability and reproducibility tests are not always very good (see above <6 C) and other non-standardized methods can be used such as DSC and thermomicroscopy. These thermal analytical methods were successfully applied to neat petrodiesel and crude oils [9, 19, 26, 33] but also to engine oils [12, 16, 17, 27, 35],... 

The Uterature on thermal analytical methods is widely scattered because it is generally abstracted under the application heading rather than under the method heading. The American Chemical Society publishes its Chemical Abstracts, which embrace most published research papers, and all the articles which contain thermal analysis data then appear in CA. Select Abstracts on Thermal Analysis. There are two international journals that publish papers on... 

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