Studies on oxidative modifications of cellulose in the periodate system: Molecular weight distribution and carbonyl group profiles

The effects of periodate oxidation on cellulose were studied by means of gel permeation chromatography (GPC) using multiple detection and carbonyl-selective fluorescence labeling according to the CCOA methodology profiling of carbonyl groups. At low degrees of oxidation, the molecular weight distribution was fully maintained. Upon more pronounced oxidation the molecular weight even increased due to cross-linking effects. More condensed structures were identified by means of light scattering. Periodate oxidation also affects crystalline regions of cellulose, as demonstrated by comparison of homogeneous and heterogeneous carbonyl labeling. Highly ordered regions in cellulose were affected by oxidation even below an oxidation degree of 2%. Two different phases for the oxidation kinetics were identified in the early stages of periodate treatments.