Nuclear Magnetic Resonance: Basic Principles and Liquid State Spectroscopy

Abstract

Thermogravimetric analysis (TGA) is an analytical technique for measuring changes in the mass of a material that occur in response to programmed temperature changes. The changes in the mass can be caused by a variety processes such as decomposition, degradation, sublimation, vaporization, adsorption, desorption, oxidation, and reduction. The article explains the principles of TGA and practical aspects of the method that include description of the apparatus, discussion of experimental variables, and applications. Among practical applications, a particular attention is paid to determining composition and thermal stability of materials, evaluating the kinetics of thermally stimulated processes, predicting lifetimes, and studying reactions of materials with gases. The article also addresses the issues of sample preparation as well as of basic analysis and interpretation of data. A special consideration is given to the sources of errors in the mass and temperature measurements as well as to the methods of calibrating both values.