Periodate Oxidation of Benzoylated Cotton

Abstract

Purified cotton yarn was partially benzoylated, with and without tension, to three low DS values averaging from 0.2 to 0.6, to retain the fibrous structure of cotton. Benzoylated and untreated yarns were oxidized by sodium metaperiodate at room temperature (32°C) for different periods (4-48 h). The oxidized samples were analyzed for their reducing power in terms of copper number. The percentage accessibility to periodate oxidation was calculated from oxygen consumption values. In most cases oxygen consumed, copper number of oxidized samples, and accessibility of benzoylated cellulose on periodate oxidation were influenced by the DS but unaffected by tensional forces on the yarn during benzoylation. Benzoylated cotton cellulose is shown to undergo oxidation at slower rate (assessed in terms of rate constant and percentage accessibility) than untreated cotton cellulose, indicating blocking of the secondary hydroxyl groups of cellulose by benzoyl groups. Further, the rate of oxidation was slower at higher DS and was independent of the tensional forces.