Enhanced functional properties of chitosan films cross-linked by biosourced dicarboxylic acids

Chitosan-based films were developed using different biosourced dicarboxylic acid solutions (succinic acid, adipic acid, suberic acid and sebacic acid). The effect of incorporating these nontoxic solutions on water vapor barrier, tensile and antimicrobial properties of chitosan films was evaluated. Fourier Transform Infrared (FTIR) and cross polarization magic angle spinning (CP/MAS) nuclear magnetic resonance (NMR) analyses were also performed to investigate functional groups interactions between chitosan and dicarboxylic acids. Acetic acid-chitosan films showed significantly higher water vapor permeability (WVP) and lower tensile strength (TS) and elongation at break (%E) than dicarboxylic acid-prepared films (p < 0.05). Using either adipic acid or suberic acid solutions to fabricate chitosan films reduced WVP by 85% and enhanced TS by 21 to 27% and %E by more than 60% when compared with the acetic acid-prepared films. Chitosan films modified with either adipic acid or suberic acid exhibited antimicrobial activity against all tested microorganisms.