Differential scanning calorimetry major applications

Interest in the use of calorimetry as a routine diagnostic or analysis tool has gained significant momentum only in the last 50 years. This interest has lead to the development of popular procedures such as differential thermal analysis (DTA) and differential scanning calorimetry (DSC). A wide variety of solution calorimetric techniques exist today. These techniques include thermometric titration, injection and flow emhalpimetry. The major growth of commercial instrumentation for calorimetry has occurred to address applications in routine analysis and the rapid characLerizaiion of materials. 

Spectroscopy has become a powerful tool for the determination of polymer structures. The major part of the book is devoted to techniques that are the most frequently used for analysis of rubbery materials, i.e., various methods of nuclear magnetic resonance (NMR) and optical spectroscopy. One chapter is devoted to (multi) hyphenated thermograviometric analysis (TGA) techniques, i.e., TGA combined with Fourier transform infrared spectroscopy (FT-IR), mass spectroscopy, gas chromatography, differential scanning calorimetry and differential thermal analysis. There are already many excellent textbooks on the basic principles of these methods. Therefore, the main objective of the present book is to discuss a wide range of applications of the spectroscopic techniques for the analysis of rubbery materials. The contents of this book are of interest to chemists, physicists, material scientists and technologists who seek a better understanding of rubbery materials. 

Polymorphism and kinetics of crystallization of TAG and fat under static conditions (e.g., in differential scanning calorimetry [DSC] apparatus) have been studied for a long time and are summarized in many reviews (2-6). Yet, these conditions are far-removed from industrial applications, where crystallization is usually achieved under shear (dynamic). Shearing has a major effect on crystallization kinetics it induces a faster and more homogeneous crystallization, often in the stable form and with a refined grain size. Yet, its effect is far from being fully understood. Recently, several studies of dynamic crystallization of lipids have been reported (7-12). 

Thermoanalytical techniques have had a major application in the understanding of transitions in the skin and of drug penetration of the skin. The application of thermoanalytical techniques to prosthetics and implants is also discussed, as are recent DSC investigations of the oesophagus that provided the information on thermal stability required for successful stent implantation. The use of thermoanalytical techniques such as modulated temperature differential scanning calorimetry (MTDSC) has been be used to characterise polymeric material in order to determine whether there are interactions with drug substances to control and predict drug delivery. 

A major application of dynamic hot stage microscopy is the study of polymer structure, as a function of temperature, in the optical microscope [12, 111]. Thermal analysis in the optical microscope is complementary to thermal analysis by such methods as differential scanning calorimetry (DSC) and differential thermal analysis (Section 6.4.2). It is now possible to observe the sample in the OM and simultaneously obtain the DSC trace. 

It has to be emphasized, however, that despite the uncontested importance of the vibrational spectroscopies for the characterization of maaomolecular stmcture, only a limited number of problems may be solved by the exclusive application of these techniques. Thus, in the majority of analytical investigations of polymer constitution and any additives, chemical separation of the components is inevitable a more complete picture of the sequence distribution and stereoregularity of stmctural units in polymers is obtained only in combination with NMR spectroscopy the results of vibrational spectroscopic investigations of polymers at elevated temperatures are advantageously correlated with differential scanning calorimetry (DSC) and last but not least, a thorough knowledge of the stmcture of crystalline polymers cannot be attained without application of X-ray diffraction. These few, far from comprehensive, examples demonstrate that maximum... 

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