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Degradation Studies of Gamma Irradiated Poly (Vinyl Alcohol)

B. Sanjeeva Rao, E. Venkateswar Rao, V. V. Rama Rao, K. Somi Reddy, K. Rajendra Prasad and Ch. Srinivas

Degradation of poly (vinyl alcohol) (PVAL) by gamma rays has been studied by electron spin resonance (ESR) technique. ESR spectra of irradiated PVAL are recorded in the temperature range of RT. (300 K) – 410 K. The spectrum is basically a triplet with intensity distribution of 1 : 3 : 1 and hyperfine splitting of 35G. The spectrum is assigned to the free radical of the type ~ CH2-C-(OH)-CH2 ~ formed by the cleavage of hydrogen from PVAL on gamma irradiation. The hyperfine pattern gradually increases up to 360 K beyond which the ESR signal gradually decrease with temperature and finally disappeared around 410 K. Free radical concentration at different temperature have been calculated and compared.