Characterization of the interaction between chitosan and inorganic sodium phosphates by means of rheological and optical microscopy studies

The physicochemical and rheological properties of chitosan and two different inorganic sodium phosphate dispersions (NaH2PO4 and Na3PO4) were investigated in order to elucidate the role of different factors, such as ratios between polymer and sodium inorganic phosphates, different pHs and storage stability, on the gelling properties of chitosan. This was deemed opportune since physico-chemical characterizations of chitosan in the literature often appear incomplete and questionable. We also compared the elastic modulus values of the different chitosan/inorganic phosphate systems and examined their behaviour through optical microscopy analyses. st efficient formulations that showed a thermogelling capacity with a significant gel transition behaviour after 24 h were the NaH2PO4/chitosan and Na3PO4/chitosan systems at ratio 2 and pH 7.0. results confirmed the importance of the pH value and ratio selection for the final systems.