Structural characterization of chitosan and oxidized carboxymethyl cellulose based freeze-dried films

The conversion of dihydroxyl groups to dialdehyde by periodate oxidation is a useful method widely used in derivatization of cellulose. Periodate oxidation is a highly specific reaction to convert 1,2-dihydroxyl groups to paired aldehyde groups without significant side reactions. This reaction cleaves the C2–C3 bond; the resulting compound is the dialdehyde cellulose (DAC). These aldehyde groups of carboxymethyl cellulose interact with amino group of chitosan and their interaction results in the formation Schiff’s base with enhanced properties of both the polymers, i.e., of chitosan and carboxymethyl cellulose. Interaction of chitosan and oxidized carboxymethyl cellulose (OCMC) has been carried out with three combinations, i.e., 5, 10, and 15 wt% OCMC with rest of chitosan in 2% lactic acid solution. This new compound is covalently crosslinked which has been analyzed by various techniques like FTIR, TGA, XRD, and SEM.