Differential scanning calorimetry thermogram analysis

There has been some interest in thermal analysis methods for permanence evaluation. An attempt was made to correlate various features of differential scanning calorimetry thermograms for a group of papers with their stability under oven aging. In some cases, the correlation coefficient was encouragingly high but the standard error of estimate showed that the relation was no more useful for predicting permanence than was pH. 

Probably the main weakness of DTA as a method of analysis remains the difficulty of linking the thermal changes shown on the thermogram, with the actual thermal processes taking place. It should be noted that data obtained by DTA are often similar to those available for differential scanning calorimetry. Indeed the two techniques overlap extensively and may be seen as complementary. A comparison of the two techniques is made at the end of the next section. 

The hydrolyses of all the propellants tested (M1, M8, and M28) formed some solid residue, the analysis of which was not pursued. However, differential scanning calorimetry analysis showed no significant exotherms in the thermograms of the residues from any of the propellants. 

PLCL (50 50) copolymers were basically random and amorphous. However, two values of were observed by differential mechanical analysis (DMA) and maybe also by differential scanning calorimetry (DSC) thermograms (Fig. 3.6 Jeong, 2004a). Furthermore, micro domains (about 17 nm size) were indicated on SAXS profile and finally confirmed by transmission electron microscopy (TEM) (Fig. 3.7). Therefore, the PLCL copolymer was probably composed of a soft matrix of mainly caprolactone moieties and... 

The most detailed thermodynamic analysis of protein structure stability is based on differential scanning calorimetry (DSC). In a DSC experiment, the heat capacity Cp of a sample is monitored while heating (or cooling) the sample. Figure 13.13 shows a typical DSC thermogram for heat-induced denaturation of a protein in solution. The thermodynamic observables are the temperature of denaturation (the temperature at half-peak area), the enthalpy change An, d (T involved in the denaturation process (the area under the peak), and the change in the heat capacity A,, dC of the solution (the shift of the baseline). 

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