The effect of ionic crosslinking on thermal properties of hydrogel chitosan membranes

Ionically crosslinked one‑component chitosan (Ch), two‑component chitosan/sodium alginate (Ch/NaAlg) and chitosan/pentasodium tripolyphosphate (Ch/TPP) membranes as well as three‑component chitosan/sodium alginate/pentasodium tripolyphosphate (Ch/NaAlg/TPP) membranes were prepared. Formation of ionic interactions between Ch and NaAlg and/or TPP was confirmed by FTIR analysis. An effect of a crosslinking process on thermal properties of hydrogel membranes was examined using TG/DTG/DTA and DSC methods. Changes in the number of thermal degradation steps of the studied hydrogel membranes were observed. Considering the temperature at which thermal degradation starts as a criterion of the thermal stability, it was concluded that the thermal stability increases according to the series: Ch/NaAlg ≈ Ch/NaAlg/TPP ≈ Ch/TPP