Studies on the acid degradation of cellulosic fibres. II. Effect of pulp characteristics on the course of degradation in hydrochloric acid-zinc chloride solution

Abstract

Heterogeneous hydrolysis of cotton cellulose ( I), alkali-treated cotton ( II) and bagasse cellulose ( III) was studied under mild conditions using 0·5 n hydrochloric acid solution. The degradation of the three pulps takes place in two stages, namely, an initial rapid stage followed by a slower hydrolysis reaction. The tendency of the cellulose structure towards degradation, measured by the rate of chain scissions, is in the order I> II> III. Hydrolysis involves ‘amorphization’ and then ‘crystallization’ of the supermolecular structure. It was found that the extent of the ‘amorphization’ depends on the properties of the starting cellulose pulp. The changes in the rate of degradation as well as the modification in the fine structure which takes place on addition of zinc chloride to the reaction mixture are discussed.