Abstract
Functional groups and degradation of cotton oxidized by hypochlorite at several pH values in the range 5β10 were studied. The carboxyl group content of the oxidized cottons increases, while the aldehyde and ketone group contents decrease with increase in pH. Approximately 40% of the oxidant consumed is accounted for by the functional groups at all pH values. The ratio of carboxyl, aldehyde, and ketone groups formed per scission is 1β1.5:3:3.5 at the acidic pH range and 5:0.8:0.0 at pH 10. Oxygen consumption per scission is 26 atoms, out of which 10.4 atoms are accounted for by the functional groups. The rest of the oxygen is explained by oxidation of the soluble products of the short chain material in the fiber phase and by the functional groups of the short chains with D.P. up to 37. The degradation was found to be random at the whole pH range studied, as proved by the ratio of the numberβaverage and weightβaverage molecular weights and by the linearity of the plot of log [Ξ·] vs. log (O~c~ + O~__c__0~) where O~c~ is the oxygen consumed and O~co~ a constant. It is suggested that the degradation and oxidation reactions occur simultaneously and, at a given pH, with similar rates, so that all carbon atoms of an anhydroglucose unit in all chains of the amorphous phase will have a similar probability of being attacked.