Preparation and characterization of chitosan films, crosslinked with symmetric aromatic dianhydrides to achieve enhanced thermal properties

This study has developed a new generation of crosslinked chitosan-based films using symmetric aromatic dianhydrides as crosslinking agents. The formation of the dianhydride-crosslinked chitosan hydrogel films was confirmed using Fourier transform infrared and solid-state C-13 NMR spectral analyses. The films obtained from these derivatives were characterized by their thermal, swelling and hydrophilic properties. The results showed that introducing a cyclic imide moiety into the chitosan matrices played a significant role in enhancing the thermal properties of these chitosan films. It was found that even at high levels of substitution, thermal stability of the studied chitosan derivatives was improved, in spite of a reduction in crystallinity. Heterocyclic imide linkages produced networks that were insoluble in both acidic and alkaline media but allowed swelling in aqueous media. An increase in the hydrophobicity of the chitosan film surfaces was observed after introduction of the cyclic imide moiety. These engineered films produced noteworthy results concerning their thermal and swelling properties. There is a need to further investigate these films for drug delivery and biomaterials applications. (c) 2014 Society of Chemical Industry