Differential thermogravimetric

Thermoanalytical method is one of the widespread methods of physical and chemical reseai ches. Considerably broadens its possibilities combination with methods differential-thermal (DTA), differential-thermogravimetric (DTG), thermogravimetric (TG) analyses. 

Figure 7 Thermogravimetric and differential thermogravimetric curves of NBR and HNBR. Source Ref. 134.

DTGA differential thermogravimetric EUPE European Union of... 

Fig. 14. Differential Thermogravimetric Analyses of Ethylene-Vinyl Acetate. ZB - Zinc Borate, ATH - Alumina Trihydrate. Zero values for the ordinates of success curves are at about 10%/min. intervals.

Figure 2. Thermogravimetric and differential thermogravimetric curves (TG and DTG) of melamine, heating rate 10 C/min nitrogen, 60 cm3/min.

Figure 20.1 show as an example the thermogravimetric crave (TG) obtained for the natural ilhte. A continuous weight loss can be seen between 150°C and 980°C the differential thermogravimetric curve (DTG) showing two endothermic effects. The first one is centered at 150°C which corresponds to loss of ilhte water. The second one is centered about 580°C and is mainly associated to the loss of stractural water. 

Examination of the thermal stability of the polyimides synthesised, carried out using differential thermogravimetric analysis (air, AT = 4.5 °C/min), revealed that, under the conditions specified, the 10% weight loss (used as a criterion of thermal stability) is almost independent of the structure of the polyimides (Table 5.1). For all polyimides examined, the 10% weight loss temperature was 400 °C. The relatively low thermal stability of these polyimides may be related to the presence of the methoxy groups. 

Transparent yellow iron oxide has the a-FeO(OH) (goethite) structure on heating it is converted into transparent red iron oxide with the a-Fe203 (hematite) structure. Differential thermogravimetric analysis shows a weight loss at 275 °C. Orange hues develop after brief thermal treatment of yellow iron oxide and can also be obtained by blending directly the yellow and red iron oxide powders. 

The DTG curves of as-synthesized samples (11-IV) are shown in Fig. 5. At least three distinguishable peaks are observed in the differential thermogravimetric (DTG) curves. Those are supposed to be related with water and MTAB cations interacted with silicate species and TPA cations trapped in the channels of silicate-1, respectively. There are four distinct stages of weight loss in the DTG data shown 23-150°C (due to the desorption of... 

Figure 7 Differential thermogravimetric (DTG) traces of the reduction behaviour of a NisAl2 coprecipitate calcined at various temperatures (M. R. Gelsthorpe, Ph.D. Thesis, University of Bradford, 1983)...

FIGURE 9.17 Differential thermogravimetric analysis of EVA-containing alumina trihydrate (A l I I) and Firebrake ZB. 

Two crystal modifications and an amorphous phase were found for 24 by X-ray diffraction and differential thermogravimetric analysis [91KFZ(3)78]. The structure of a complex formed from 3-[p-methylphenyl)amino]-4-[(p-methylphenyl)imino]-4//-pyrido [1,2-a]pyrazine, sodium bis(trimethylsi-lyl)amide and (norbomadiene)Mo(CO)4 in THF was characterized by single-crystal X-ray diffraction [95JPR(337)38],... 

We used thermal analysis to determine the thermogravimetric analysis (TGA) and the differential thermogravimetric analysis (DTG) of SCT pitches to obtain information on volatility and coke yield at various temperatures up to 1000°C, DTG was found very useful in defining process modifications to reduce volatiles in the pitch and increase pitch coke yield. Figure 3 gives the DTG (in nitrogen) of several SCT pitches prepared by distillation, thermal and catalytic process, in comparison with petroleum and coal tar pitches,... 

Figure 3. Differential thermogravimetric analysis (DTG) in nitrogen of SCT, petroleum, and coal tar pitches.

Differential Thermal Analysis (DTA), Thermogravimetric Analysis (TGA), and Differential Thermogravimetric Analysis (DTG) of Potato Starch Dried by Three Methods (All Temperatures in °C)3SS... 

Figure 4. Thermo gravimetric and differential thermogravimetric curves of the asphaltenes (Cs) from a 525+ ° C Oficina residue...

But close examination of the differential thermogravimetric trace reveals that, although major losses occur at 500° C, some product disappears slowly between 600° and 900° C. This might be attributable to the beginning of a breakdown of the more fragile parts of the molecules (29). This is the reason why it is so important to closely control time and temperature in the program, or at least to hold them constant from run to run. 

The thermal techniques most commonly used to investigate the acid-base or redox character of soHd surfaces are differential thermal analysis (DTA), thermogravi-metric (TG) and differential thermogravimetric (DTG) methods, differential scanning calorimetry (DSG) and calorimetry. These techniques can be used either by themselves, or in conjunction with other techniques (for instance, TG-DSC, calorimetry-volumetry, DSG-chromatography, etc.) [5, 6]. 

TGA, Differential Thermal Analysis (DTA) and Differential Thermogravimetric Analysis (DTG) measurements have been employed to determine the number and nature of water molecules present in the POMs. The results of TGA show the presence of two types of water in POM compounds, namely water of crystalHza-tion and constitutional water molecules. The loss of the former usually occurs at temperatures below 443-473 K [141]. At temperatures exceeding 543 K for H3PM012O40 and 623 K for H3PW12O40, the constitutional water molecules (the acidic protons bound to the oxygens of the polyanion) are lost, according to the literature and for the acid forms [140]. For example the thermolysis of H3PM012O40 proceeds in two steps as schematized below ... 

Fig.5. Thermogravimetric analysis (a), differential thermogravimetric analysis (b), and differential thermal analysis (c) of as synthesized ZGctab sample.

Thermogravimetric analysis Dynamic thermogravimetric analysis Differential thermogravimetry Differential thermogravimetric analysis... 

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