ON THE FREE-RADICALS PRODUCED IN GAMMA-IRRADIATED POLYACRYLAMIDE

Nature of free radicals produced on gamma-irradiation of polyacrylamid e (PAAm) have been investigated by electron spin resonance (ESR) spect roscopy. The ESR spectrum observed for irradiated PAAm at room tempera ture (RT) is a triplet with hyperfine (hf) splittings of 24 G and inte nsity distribution of 1:3:1. Superposition of component triplet, toget her with a singlet originating from a different radical is found to be the best fit to the experimental spectrum as RT, as has been deduced from the total curve fitting method. The ESR spectrum of irradiated PA Am at liquid nitrogen temperature (LNT) is a sharp singlet. The spectr a at RT and LNT are attributed to different interconvertible forms of the free radicals of the type approximately CH2-C(CONH2)-CH2 approxima tely. A mechanism for radiative degradation of PAAm is proposed.