ABSTRACT Proton Magnetic Resonance Thermal Analysis (PMRTA) has been proven to be a powerful and convenient technique for the thermal analysis of hydrogen containing solid organic materials such as coal, and is now finding application to the study and characterization of polymers. In this technique the proton magnetic resonance (1H NMR) transverse, or spin-spin relaxation is recorded while the sample is being heated. This spin-spin relaxation signal is sensitive to aspects of molecular dynamics and structure so that, for example, rigidly bound molecules give rise to a rapidly decaying signal while the acquisition of molecular mobility leads to a slower decay. In some instances the spin-lattice relaxation behaviour can also be monitored. PMRTA, then, monitors physical and chemical changes in the sample that lead to alterations in the interactions between magnetic species such as occur, for example, in glass transitions, melting, crystallization, thermal degradation and decomposition, polymerisation and free radical formation and quenching. The PMRTA technique was initiated by Lynch and Webster in the early 1980`s and has resulted in the development of a commercially available instrument. In this article the principles of PMRTA and the instrumentation are briefly reviewed and examples which illustrate the range of information obtainable are drawn from measurements on a variety of polymers and other solid organic materials.
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