Title 34. THERMAL ANALYSIS.pdf ✅

PHARMD GURU Page 2  Calorimetry is the process of measuring the amount of heat released or absorbed during a chemical reaction and the device is known as calorimeter.  Watson and O'Neill developed this thermal analysis in 1960 and then introduced it in 1963 commercially at Pittsburgh Conference on Analytical Chemistry and Applied Spectroscopy. PRINCIPLE: The basic principle involved in DSC is that this technique is used to study what is the effect of heating on the polymers/samples. It examines the thermal transitions of polymer or sample when heated. For example, this technique can be employed to study the effect of heating on a crystalline polymer, glass transitions, and crystallization. The sample and reference materials are heated by separate heaters at the same temperature throughout the experiment. The energy which is required to obtain zero temperature difference between sample and reference is measured. INSTRUMENTATION: FIG: SCHEMATIC REPRESENTATION OF DSC APPARATUS  The DSC measurement requires a sample and a reference.  Modern DSC sample and reference pans are small and usually made of aluminum. They may or may not have lids.  Sample size is generally 1-10 mg and the reference pan is left empty, but an inert reference material may be used.