Sodium lactate loaded chitosan-polyvinyl alcohol/montmorillonite composite film towards active food packaging

- Incorporation of MMT improves barrier and mechanical properties significantly.
- Initial diffusion of sodium lactate can be well described by Fickian equation.
- Diffusion of sodium lactate is strongly dependent on pH and ionic strength.
- Film shows good antimicrobial activity and well controlled release.

A sodium lactate loaded chitosan-polyvinyl alcohol/montmorillonite (NaL-CS/PVA/MMT) barrier film with antibacterial activity was developed by coating method and the effectiveness and diffusion behavior were investigated. An intercalated structure was achieved for CS/PVA/MMT film and the interfacial interactions among CS, PVA and MMT were intermolecular hydrogen bonds. An appropriate increase of MMT contents (15 wt% and below) could achieve a remarkable enhancement in tensile strength and Young's modulus, meanwhile, the water vapor, oxygen and carbon dioxide barrier properties of the films were also significantly improved. The NaL-CS/PVA/MMT film exhibited good antibacterial activity against E. coli and well controlled release of NaL. Moreover, the diffusions of NaL from films were dependent on the pH value of aqueous solution and ionic strength, and the initial diffusions (Mt/M∞ < 2/3) could be well described by Fickian equation. The NaL-CS/PVA/MMT film may have potential as a good barrier film with antibacterial activity towards food packaging.