DSC method

Vicat softening point ( C) ASTM D1525 (DSC method) 39 52 66... 

The fibers of draw ratio 1.5 x were annealed unstressed in the dryer for 2 h in air. Determined by dsc method. 

In the DSC method, the sample and reference are maintained at the same temperature and the heat flow required to keep the equality in temperature is measured. Hence DSC plots are obtained as the differential rate of heating (in units of watts/second, calories/second, or Joules/second) against temperature. The area under a DSC peak is directly proportional to the heat absorbed or evolved by the thermal event, and integration of these peak areas yields the heat of reaction (in units of calories/second gram or Joules/second gram). 

Chemiluminescence is the emission of light in the 300-500 nm region due to exothermic chemical reactions. With a suitable detection system this can be used to monitor the chemical reactions that occur when materials age. This technique is sensitive enough to produce results more rapidly and at lower temperatures. Chemiluminescence has been used to investigate the effect of different additives on the oxidation of polymers as well as to determine oxidation induction times which are more meaningful than those obtained from the DSC method. 

The versatility of the DSC method and the high speed of the experiments have costs in terms of accuracy. For example, the best accuracy in the determination of heat capacities of solids by DSC is typically 1% [3,248-250], at least one order of magnitude worse than the accuracy of the corresponding measurements by adiabatic calorimetry [251]. This accuracy loss may, however, be acceptable for many purposes, because DSC experiments are much faster and require much smaller samples than adiabatic calorimetry experiments. In addition, they can be performed at temperatures significantly above ambient, which are outside the normal operating range of most adiabatic calorimeters. 

Weight Percent of a Hydride Phase and Hydrogen by DSC Method... 

M. Mamatha, C. Weidenthaler, A. Pommerin, M. Felderhoff, F. Schuth, Comparative studies of the decomposition of alanates followed by in situ XRD and DSC methods , J. Alloys Compd. 416 (2006) 303-314. 

Since procaine hydrochloride melts without decomposition, the DSC method can be used to establish the absolute purity of the material. The DSC purity of the tested sample was found to be 100.14 mole%, and the enthalpy of fusion for this sample was determined to be 31.5 kJ/mole (7.52 Kcal/mole). 

Determination of the reaction rate from calorimetric measurements, using DSC technique, is very useful and was applied with success for many template polymerization systems and for blank polymerizations.Two types of calorimetric measurements were described isothermal and scanning experiments. The heat of polymerization can be measured by DSC method, measuring thermal effect of polymerization and ignoring the heat produced from decomposition of the initiator and heat of termination. In isothermal experiments sample is placed at a chosen temperature and thermogram is recorded versus time. Assuming typical relationship... 

A study of benzocyclobutene polymerization kinetics and thermodynamics by differential scanning calorimetry (DSC) methods has also been reported in the literature [1]. This study examined a series of benzocyclobutene monomers containing one or two benzocyclobutene groups per molecule, both with and without reactive unsaturation. The study provided a measurement of the thermodynamics of the reaction between two benzocyclobutene groups and compared it with the thermodynamics of the reaction of a benzocyclobutene with a reactive double bond (Diels-Alder reaction). Differential scanning calorimetry was chosen for this work since it allowed for the study of the reaction mixture throughout its entire polymerization and not just prior to or after its gel point. The monomers used in this study are shown in Table 3. The polymerization exotherms were analyzed by the method of Borchardt and Daniels to obtain the reaction order n, the Arrhenius activation energy Ea and the pre-exponential factor log Z. Tables 4 and 5 show the results of these measurements and related calculations. 

In contrast to the DSC method, the colorimetric method determines the hydroperoxide decomposing capabilities of the antioxidant species in the oil sample (Enmanji, 1979). 

The colorimetric method is much less expensive and much easier to operate in comparison to DSC methods. It is capable of accurately predicting the operating time at which oil samples possess 0 hours of the residual useful life (RUL). 

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