ROLE OF TEMPERATURE AND SAMPLE-SIZE IN RADIATION OXIDATION OF POLYETHYLENE

It was found that the radiation yield of > C = O, -OH, and -OOH groups is a function of the absorbed dose rate as G approximately D-0.5 in oxidation of polyethylene (PE) initiated by x-ray radiation in the 298-353 K range. The effective activation energies of the rates of initiation of oxidation of PE and accumulation of > C = O and -OH groups are respectively equal to -80 +/- 20, 13, and 16 kJ/mole. The distribution of > C = O groups in thick samples is described by diffusion equations. An increase in the temperature causes an increase in the depth of the oxidation reaction.