Microstructure and properties of thermomechanically processed chitosan citrate-based materials

The traditional solvent casting method for preparing chitosan-based materials has limited productivity relative to the productivity of thermomechanical processing. Consequently, the thermomechanical processing technique was evaluated as a way to increase chitosan production. The role of citric acid (CA) as a destructuring and crosslinking agent during such processing was examined. SEM images revealed robust fibers that were associated with a superior mechanical strength (145%), which were produced after thermomechanical processing of chitosan in the presence of CA. Based on articles reviewed, this is the first time that this structure has been closely observed in the microstructure of chitosan-based materials. FTIR and XRD characterization showed the occurrence of chemical crosslinking and the successful destructuring of chitosan powder by CA during processing. Compared to acetic acid, the use of CA led to the development of materials with a homogeneous morphology and good physicochemical and mechanical properties that are suitable for biomedical applications.