4-O-METHYL-D-GLUCURONO-D-XYLAN DEGRADATION BY GAMMA-IRRADIATION .1. DOSE EFFECTS ON THE MACROMOLECULAR PROPERTIES

The degree of polymerization and molecular weight distribution of 4-o-methyl-D-glucurono-D-xylan is compared before and after gamma-irradiation. With increasing the radiation dose, the profile of the distribution curve becomes broadened and the molecular weight peaks are shifted to lower values. The radiation-chemical yield of cleaved glycosidic bonds G was found to be 8 +/- 1 scissions per 100 eV of energy absorbed. The poly-dispersity index MBARw/MBARn increased from 1.5 to 1.9, thus indicating a random scission of the xylan chain.