Mahua oil-based polyurethane/chitosan/nano ZnO composite films for biodegradable food packaging applications.

Biodegradable food packaging films were fabricated from Mahua oil-based polyurethane (PU) and chitosan (CS), incorporated with different proportions of zinc oxide nanoparticles. The structure and properties of the solvent-cast films were evaluated. PU/CS with 5% nano ZnO composite film showed improved tensile strength and stiffness. The incorporation of zinc oxide nanoparticles enhanced the antibacterial properties, barrier properties and hydrophobicity of the film. The weight loss of PU/CS/5% nano ZnO biodegradable film was 86% after 28 days in the soil. The shelf life period of carrot pieces wrapped with the composite film was extended up to 9 days. The film containing zinc oxide nanoparticles was effective in reducing the bacterial contamination when compared to the commercial polyethylene film. In essence, the composite film possessed all desirable characteristics to be considered as a food packaging material that has been fabricated from low environmental impact bio-polyol based polyurethane.