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Nuclear Resonance Studies of Polymer Chain Flexibility
註釋Molecular movement underlies many of the familiar properties of high polymers. It is important in such diverse phenomena as rubber elasticity, viscous flow, dielectric loss, and the melting of crystalline regions. The flexibility of polymer molecules involves not only features of structure within individual chains but also constraints between neighboring chains. There is as yet no explicit measure of what we mean by "flexibility," but there are several important methods for detecting motion in molecules. Among these are dielectric relaxation studies and a variety of mechanical measurements. One may also deduce molecular motion from studies of structural transitions, using techniques such as X-ray diffraction and calorimetry. To these familiar techniques there has quite recently been added an important new method--nuclear magnetic resonance spectroscopy (NMR).