Chitosan-vanillin composites with antimicrobial properties

In this work there are described the obtaining and characterization of composite films containing chitosan, vanillin and Tween 60. Vanillin was used as cross-linker of chitosan. The composites were characterized by various methods like Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), X-ray diffraction (XRD) and solid state 13C nuclear magnetic resonance (CP/MAS 13C NMR), which have proved the formation of a Schiff base between chitosan and vanillin. Scanning electron microscopy (SEM) has also enlightened a strong interaction between the components. Tween 60 has influenced the value of water vapour transmission rate (WVTR), all the composites that contain Tween 60 having a low value of this parameter. Due to the fact that not all the vanillin is consumed in the Schiff base reaction, these composites could be used for vanillin delivery. After having studied the release behaviour we have concluded that most probably it is governed by crystal dissolution and Fick's diffusion law. Antimicrobial activity was highlighted using Escherichia coli (ATCC 8737) strain, all the composites having a good antimicrobial activity.