Effect of gamma‐radiation on cellulose

Abstract

AbstractCotton and wood cellulose were irradiated with gamma rays within the dosage range 60 X 103 r to 2,300 X 103 r. A measure of the degradation was obtained from intrinsic viscosities obtained from viscosity determinations in cupriethylenediamine solution. The presence of water had no significant effect on the extent of radiation‐induced degradation. Thus there was little or no difference between the results on irradiated samples of wood cellulose containing 3.3, 4.6, and 5.6% moisture. Cotton cellulose irradiated in the presence of excess water or 3.5% moisture was equally degraded. At lower moisture levels (0.26–0.32%) an aftereffect was observed in which the solution viscosities of the irradiated samples progressively decreased up to 30 days in storage. The duration of the effect was independent of the dosage levels studied. From the experimental results reported here and from recalculations of data in the literature the radiation threshold dosage for isolated celluloses appears to be in the range of 28.4 to 81.2 X 103 r. Cellulose is degraded at gamma‐radiation dosages equal to or below those required for softening plant tissues such as apples, carrots, and beets. Therefore it seems probable that the degradation of this cell wall constituent is a major factor in the radiation‐induced softening of plant tissues.