Application of Bloch Analysis to Evaluate Activation of Energy of Irradiated Polyacrylonitrile

Abstract

Abstract

Polyacrylonitile is one of the important polymers of technical and scientific importance. During its usage, the polymer is exposed to different types of radiations, limiting its use. In order to investigate the processes involved in radiation effect in PAN, various efforts have been made. In this context, the authors have also made an attempt to investigate radiation induced process in PAN by electron spin resonance (ESR) technique. ESR spectra of PAN irradiated to 10 Mrad radiation dose have been recorded at various temperatures. The spectrum at room temperature is a broad singlet with some hyperfine structure with the increase of temperature. The hyperfine structure gradually increased initially and then again retained its shape at higher temperatures. The signal totally vanished at a temperature of 405 K. Recombination of free radicals is thought to be associated with disappearance of free radicals at 405 K. In order to find activation energy associated with free radical decay at 405 K Bloch analyses is applied. Measuring the values of line widths for intermediate and fast decay, the value of correlation times are measured at different temperatures. A plot of (1/T) against log (1/τ) is drawn. The slope of the straight line gives activation energy for recombination of free radicals.

Keywords: Polyacrylonitile, PAN, electron spin resonance, Bloch analysis

Cite this Article

Muralidhar J, Jeevan Kumar R, Sanjeeva Rao B, et al. Application of Bloch Analysis to Evaluate Activation of Energy of Irradiated Polyacrylonitrile. Journal of Polymer & Composites. 2016; 4(2): 25–28p.