Peak temperature of melting

The peak temperature of melting (T p). Unfortunately, in many publications, this is reported as the melting point. It should be remembered that this temperature indicates the maximum rate of melting. 

Figure 2.48. Characteristic temperatures of a polymer melting, and determination of the sigmoidal basehne numbers 1 indicate spots where the cursor should be put down to determine the sigmoidal baseline. Unless the four points can be put on the same line, the sigmoidal baseline option should be used. If the four points are on the same hne, yon can stUl nse the sigmoidal baseline option, but then the basehne will be straight. (Ta = starting temperature of melting, = peak temperature of melting,...

The sample thermogram by the presence of an endotherm associated with a melting transition, and characterized by onset and peak temperatures of 0.29 and 5.65°C, respectively, and an enthalpy of... 

Figure 3.30 shows the DSC traces for the (MgH + 20, 30, 50 and 70 wt%LiAlH ) composites. Only single endothermic peak centered at 350°C is visible in DSC traces for the (MgH + 20 wt%LiAlH ) composite (Fig. 3.30a). This peak corresponds to the decomposition of MgH. The first low temperature exothermic effect observed in Fig. 3.9 for a pure LiAlH (both unmilled and milled), which is usually assigned to the interaction of LiAlH with hydroxyl impurities [67], is not observed in Fig. 3.30a-c but it appears in Fig. 3.30d for (MgH + 70 wt%LiAlH ). Four endothermic events occur for (MgH + 30, 50 and 70 wt%LiAlH ) (Fig. 3.30b-d). The first endothermic peak at 174-182°C has almost exactly the same temperature range as (Rla) in Fig. 3.9. No exothermic peak (Rib) of melting from Fig. 3.9 is seen in Fig. 3.30a-d. It seems that the addition of just 30 wt%MgH suppresses melting of LiAlH and its first decomposition into LijAlH and Al ((Rib) in Fig. 3.9) occurs from a solid phase and is endothermic. This is supported by the observation of partial decomposition of LiAlH into (LijAlH + Al) during milling as discussed before. The second endo peak in Fig. 3.30b-d at 198,193 and 223°C, respectively, corresponds to the decomposition...

Fig. 3.46 (a) The temperature of melting and decomposition peaks of NaBH for all composites from Figs. 3.44 and 3.45 as a function of the MgH content. Numbers in parenthesis show the number of multiple data points for this specific composition. Data for the (NaBH + Xwt%Mg) mixtures where Xwt% is an equivalent amount of Mg corresponding to the Mg decomposed from Xwt%MgHj are also included, (b) Analysis of the yield of MgB based on the Vajo et al. [196-198] model adopted for the (NaBH + MgH ) system... 

DSC experiments were conducted up to 500 and 600°C for the ball-milled mixtures of NaBH with 12, 55, 73 and 92 wt%Mg (DSC traces not shown here). The temperatures of melting and decomposition peaks of NaBH are plotted in Fig. 3.46a. It is seen that the data points for the equivalent content of 12, 55 and 73 wt%Mg follow quite closely the data points for MgH. Only data points for the equivalent content of 92 wt%Mg show slightly higher decomposition temperature than their MgH counterpart and lie slightly above the ROM line for MgH. This behavior is probably related to different mechanical properties of Mg and MgH which results in different abilities to particle and grain size reduction during the milling process as can be seen in Fig. 3.47. The particle size reduction of ductile... 

The peak temperature of the major endotherm (Tm) and the total enthalpy for the melting of crystals of artemisinin 1 were reported <1997P1209>. 

Hewins R. H. and Connolly H. C., Jr. (1996) Peak temperatures of flash-melted chondrules. In Chondrules and the Proto-planetary Disk (eds. R. H. Hewins, R. H. Jones, and E. R. D. Scott). Cambridge University Press, Cambridge, pp. 197-204. 

Indomethacin (Shen et al. 1963), one of the first nonsteroidal anti-inflammatory drugs (NSAIDs), is known to exist in three different solid forms. The three forms have different XRPD patterns, and additional chemical analysis indicates that there are no solvates involved with these three forms. Different DTA melting point behaviors (Figs. 3-1 and 3-2) are also observed, as predicted. Forms I and II show single melting point endotherms with peak temperatures of 163°C and 157°C, respectively. Form III shows an initial melting endotherm with a peak temperature of 151 °C followed by an exotherm that corresponds to the crystallization of Form I, which then melts, yielding the endotherm with a peak temperature of 163°C. 

Measurements. DSC measurements were carried out on a Perkin-Elmer instrument, Model DSC II. The scanning speed was 20°C/min in all cases, and indium was used as a standard. The temperature range scanned was — 50°-180°C. The peak temperature of the melting endo-therm was taken as the melting point of the polymer crystals. 

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