THERMAL ANALYSIS OF CHITOSAN DERIVATIVES

From the exoskeleton of marine materials, a chitinous, rigid, crystalline and insoluble material is obtained, chitin, which in an alkaline medium and high temperatures results in the structure of chitosan. Chitosan derivatives, such as hydrogel, are obtained to improve properties such as solubility, bioavailability and toxicity. Chemical modifications such as carboxylation allow the exchange of a functional group for another that confers desired characteristics. Succinylation is an example of this type of reaction, with the modification of the structure of chitosan, which reacts with succinic anhydride, being the net result of the reaction in the exchange of an amino group for an acyl group. The objective was to prepare and characterize succinyl chitosan (SQ) in terms of its thermal properties. For the deacetylation synthesis, 50% NaOH at 130°C was used. After neutralization, 2.0% of chitosan was solubilized in an acid medium (acetic acid 4.0% v/v), with succinic anhydride and ethanol, SQ was precipitated and lyophilized, turning into a gel afterwards. The thermal properties of the materials were determined by thermogravimetry (TG/DTG/DTA) and differential scanning calorimetry (DSC). The results of the thermal properties showed differences between the materials in the initial and maximum temperature of decomposition and mass loss. The thermal resistance depended on the structure of the samples, determining the following behavior: chitin > chitosan > succinyl chitosan. The DSC results show endothermic behavior in the range of 100 °C in all polymers due to water evaporation, and exothermic behavior in the range of 250 – 350°C, characteristic of decomposition. In this way, the thermal properties of the polymers were evaluated for application in baked or non-baked product formulations.