Electron Paramagnetic Resonance Spectroscopy and Forward Recoil Spectrometry

Electron Paramagnetic Resonance Spectroscopy and Forward Recoil Spectrometry 

Characterization of Polymer Blends Miscibility, Morphology, and Interfaces, First Edition. 

This review of EPR and FRES studies on polymer blends (see Sections 23.2.2 and 23.3.3) is based mainly on reports produced within the past 15 years. However, in other sections reference is also made to earlier publications concerning the development of both methods, and the most relevant data obtained via their use. 

EPR is used extensively to detect, identify and follow the fate of radicals involved in polymerization or polymer degradation processes. It is also used extensively to characterize polymeric materials in terms of their morphology, heterogeneity, structural transformations, chain dynamics, and so on [2-5]. For this purpose, one can take advantage of the stable paramagnetic centers present in material to be examined (e.g., residual post-polymerization radicals, or TMIs used as catalytic centers or stabilizers). In most cases, however, external spin probes are added, including spin-labeled macromolecules (see Sections 23.2.1.5 and 23.2.2.1) [6]. The sensitivity and high content of structural information contained in the spin Hamiltonian parameters allow to obtain valuable - and often unique - data on the studied systems [7]. 

As the theory of EPR spectroscopy has been described in numerous books and reviews [2,8-12], at this point only selected basic information will be provided that is essential for readers unfamiliar with the technique and is related to the application of the technique in polymer studies. As mentioned above, EPR spectroscopy is used to investigate substances with unpaired electrons. The electron possesses intrinsic angular momentum called spin (S), and since it is a negatively charged particle, its magnetic moment (y e) is collinear but anti-parallel to the spin itself 

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I 23 Electron Paramagnetic Resonance Spectroscopy and forward Recoil Spectrometry... 

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