Characterization and release kinetic of crosslinked chitosan film incorporated with α-tocopherol

The aim of this work was to produce the in-situ crosslinking emulsification chitosan film by the casting solution method and to study the effect of sodium tripolyphosphate (TPP), sodium citrate (CT), and glutaraldehyde (GLU) for the physical properties, barrier properties, mechanical properties, and release kinetics of chitosan film incorporated with α-tocopherol. The release of α-tocopherol to the 50% ethanol was also studied and the diffusion coefficient calculated by the Fickian diffusion models. From the results, the crosslinking agent decreased the film lightness and light barrier properties; in addition, it increases the greenness and yellowness of the film. The elongation at break (EB) and tensile strength (TS) tended to decrease when the film was crosslinked. This result can indicate that the crosslinking agent caused the chitosan networks to be linked and then affected the flexibility of the films. The crosslinking agent can increase the hydrophobicity and surface roughness of the film as shown in the increase of the contact angle values and SEM micrographs; instead, there was no significant difference in water vapor permeability values (WVP). The diffusion coefficient of α-tocopherol significantly decreased from when the film was crosslinked, and the slowest release occurred in glutaraldehyde (GLU) due to its ability to generate more crosslinking density that directly affects the mobility of α-tocopherol in the chitosan structure.