Strahleneinwirkung auf Cellulose und pflanzliche Gerüstsubstanzen

Abstract

The alterations of cellulose, hemicellulose, lignin and pectin caused by ionizing radiation are being discussed. Doses above 1 Mrad cause a remarcable degradation of cellulose, especially a splitting of the 1,4-β-glucosyl bond. Carbonyl and, to a smaller extent, also carboxyl groups are formed. Numerous break-down products appear such as mono-, di- and oligosaccharides, cellulodextrins, acids (for instance 2-ketogluconic acid and its lactone, 2-ketocellobionic acid), reductones, and gases (CO > CO₂ > H₂). Irradiated cellulose is more sensitive against the influence of cellulase, cellulose splitting microorganisms and acid hydrolysis. A radiation induced polymerization of cellulose with other substances, such as styrene, acrylonitrile, vinyl monomers, is possible.
Lignin which has a certain protecting effect on cellulose is less sensitive against irradiation than cellulose. Hemicelluloses are much easier degraded than cellulose. Pectins too, especially protopectins are very sensitive against ionizing radiation when doses surpass 0.01 Mrad. On the other hand pectin jellies made from sugar, acid and pectin are only affected by doses above 1 Mrad.