Auto-Oxidation Mechanisms of Polymer Systems

6 Auto-Oxidation Mechanisms of Polymer Systems 7.6.1 ESR Spectrum ofPeroxy Radicals in Polymer Matrices 

In general, alkyl radicals trapped in polymer materials convert to peroxy radicals when oxygen molecules are introduced. The disappearance of the double quintet due to the chain type fluoro alkyl radicals in polytetrafluoroethylene (PTFE) described 

Iwasaki et al. [28] observed the ESR spectra of peroxy radicals in irradiated powders and oriented sample of FIFE using a K-band (24 GHz) ESR spectrometer and determined the principal values and directions of the g-tensor, both at room temperature and at 77 K. 

The asymmetric component (dashed line) has a characteristic line shape arising from the axially symmetric g-tensor. From the line shape one can obtain the principal values g// = gi = 2.006 and 2.022, where g// and gx represent 

The observed value of the symmetric component at room temperature was also 2.016. These facts suggest that the apparent spectral changes at room temperature and 77 K were due to complete or partial averaging of the tensor elements by molecular motion. 

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