Differential scanning calorimetry conventional

The cure of novolaks with hexa has been studied with differential scanning calorimetry (dsc) and torsional braid analysis (tba) (46) both a high ortho novolak and a conventional acid-cataly2ed system were included. The dsc showed an exothermic peak indicating a novolak—hexa reaction ca 20°C higher than the gelation peak observed in tba. Activation energies were also calculated. 

In general, X-ray data are used in conjunction with other techniques to obtain as full a picture as possible. For liquid-crystalline materials, differential scanning calorimetry (DSC) and polarizing optical microscopy (POM) are conventionally used. 

Fig. 2 Typical thermogram obtained using conventional differential scanning calorimetry on PNIPAM solution the temperature of maximum heat capacity (Tmax), the width of the transition at half-height (AT1/2), the heat of transition (AH), the difference in the heat capacity before and after the transition (ACp), and the demixing temperature (Tdem). (Adapted from Ref. [200])...

Differential scanning calorimetry is performed at a heating rate of 2°C/min from 20°C to 100°C. The checkers used a conventional melting point apparatus. 

Hutchinson, J. M. (1998). Characterising the glass transition and relaxation kinetics by conventional and temperature-modulated differential scanning calorimetry. Thermochimica Acta 324(1-2), 165-174. 

The use of a cooling accessory permits XRD patterns to be obtained under subambient conditions. In pharmaceutical systems, the greatest utility of the technique is to monitor the crystallization of solutes in frozen solutions. Conventionally, differential scanning calorimetry has been the most popular technique for the characterization of frozen systems. However, as mentioned earlier, this technique has some drawbacks (i) It does not enable direct identification of crystalline solid phase(s). Moreover, it is difficult to draw any definitive conclusions about the degree of crystallinity, (ii) The interpretation of DSC curves is very difficult if there are overlapping thermal events. Low temperature XRD was found to be an excellent complement to differential thermal analysis in the characterization of water-glycine-sucrose ternary systems. " ... 

Nanophase materials generally have an excess heat capacity and entropy relative to the bulk. These can be obtained by conventional heat capacity measurements (adiabatic calorimetry, differential scanning calorimetry), although problems with the adsorbed water and other gases are more severe for nanomaterials than for bulk phases. Data at present are fragmentary and it is difficult to evaluate their accuracy. Dugdale et al. (1954) report on excess heat capacity for fine grained rutile. Victor (1962) report data for MgO and BeO, and Sorai et al. (1969) for Ni(OH)2 and Co(OH)2. 

Table III gives the physical and chemical properties of the M. oleifera oil. Some of the properties of the oil depend on the extraction medium. The M oleifera oil is liquid at room temperature and pale-yellow in colour. Electronic nose analysis shows that it has a flavor similar to that of peanut oil. The melting point estimated by differential scanning calorimetry is 19°C (15). The chemical properties of the oil depicted in Table III below are amongst the most important properties that determines the present condition of the oil. Free fatty acid content is a valuable measure of oil quality. The iodine value is the measure of the degree of unsaturation of the oil. The unsaponifiable matter represents other lipid- associated substances like, sterols, fat soluble vitamins, hydrocarbons and pigments. The density, iodine value, viscosity, smoke point and the colour of Moringa oil depends on the method of extraction, while the refractive index does not. Varietal differences are significant in all physical characteristics apart from refractive index and density (2). The heating profile of the M. oleifera seed oil using the differential scanning calorimetry (DSC) conventional scan rate shows that there is one major peak B and, two small shoulder peaks A and C...

An overview of analytical methods used to study oxidation was edited by Kamal-Eldin and Pokorny (2005). Numerous methods, including wet-chemical methods, such as acid value and peroxide value, various oxidation tests, pressurized and conventional differential scanning calorimetry (P-DSC DSC see Dunn 2000, 2006), nuclear magnetic resonance (NMR) and others, have been applied in oxidation studies of biodiesel. NMR can be used to assess the fatty acid profile of oxidized biodiesel (Knothe, 2006a). 

The conventional thermoanalytical techniques (thermogravimetry TG, differential scanning calorimetry DSC, differential thermal alysis DTA, etc.) can provide fundamental data concerning the thermal behaviour of these substances, but the addition of mass spectrometry (TG-MS) or Fourier transform infrared spectroscopy (TG-FTIR) has permitted the identification of gaseous species evolved during thermal processes. 

Pulse thermal analysis extends the versatility of conventional thermoanalytical methods by providing a means for studying differential reaction progresses. This advantage is combined with all the opportunities of thermogravimetry, differential thermal analysis or differential scanning calorimetry and evolved gas analysis. The primary benefits of the new method are ... 

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