Calorimetry, basic concepts

Several subjects that might be considered under the title of thermochemistry are discussed in previous chapters. Such subjects are the heat capacities of a single-phase system, the dependence of the enthalpy of a single-phase system on temperature and pressure, and the dependence of the enthalpy of a one-component, multiphase system on the temperature, volume, and mole numbers. Here we are concerned with heat capacities of multiphase systems, with changes of enthalpy for the formation of a solution and for a change of concentration of the solution, and with changes of enthalpy of systems in which chemical reactions occur. First the basic concepts of calorimetry are reviewed. 

In the following sections, the basic concepts of temperature-programmed methods (primarily temperature-programmed desorption, but also temperature-programmed reactions) are outlined. At the beginning, fundamental principles of adsorption and desorption—their thermodynamic and kinetic aspects, are presented. Furthermore, the descriptions of experimental setups, the data that can be obtained from the experiments and their interpretation are given. The possibilities to extract the adsorption energies and kinetic parameters from experimental results are discussed. Finally, the examples of possible applications and the comparison of results obtained by TPD with those obtained from adsorption calorimetry, are presented. 

Nowadays, for a thermodynainicist, /pVT-calorimetry (further referred to as scanning transitiometry, its patented and commercial name ) is the most accomplished experimental concept. It allows direct determinations of the most important thermodynamic derivatives it shows how, in practice, the Maxwell relations can be used to fully satisfy the thermodynamic consistency of those derivatives. Of particular interest is the use of pressure as an independent variable this is typically illustrated by the relatively newly established pressure-controlled scanning calorimeters (PCSC). - Basically, the isobaric expansibility Op(p,T) =il/v)(dv/dT)p can be considered as the key quantity from which the molar volume, v, can be obtained and therefore all subsequent molar thermodynamic derivatives with respect to pressure. Knowing the molar volume as a function of p at the reference temperature, Tg, the determination of the foregoing pressure derivatives only requires the measurement of the isobaric expansibilities as... 

In this chapter, the basics of differential scanning calorimetry (DSC) analysis and its correlation to polymer morphology for semicrystalline polymeric materials are presented. After a brief review of fundamental concepts, the utility of the technique is illustrated by a series of practical applications. 

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