Structural analysis, and antioxidant and antibacterial properties of chitosan-poly (vinyl alcohol) biodegradable films

The development and characterization of biodegradable blend films based on chitosan and poly (vinyl alcohol) for possible use in a variety of biological activities are reported. Fourier transform infrared spectroscopy (FTIR) spectra of chitosan-poly (vinyl alcohol) (Ch/PVA) films showed characteristics peaks shifting to a lower frequency range due to hydrogen bonding between -OH of PVA and -NH2 of chitosan. The chitosan and PVA polymers presented good compatibility. The morphology study of chitosan and composite films showed a compact and homogenous structure. The tensile strength and elongation at break increased with PVA content. In fact, the highest tensile strength and elongation at break (53.58 MPa and 454 %) occurs with pure PVA film. The results showed that PVA incorporation in the blends contributes to increase the intermolecular interactions, thus improving the mechanical properties. In addition, the prepared films demonstrated high antioxidant activities monitored by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging, reducing power, and beta-carotene bleaching activity. Nevertheless, PVA addition reduced antioxidant and antibacterial activities against Gram-positive and Gram-negative bacteria tested.