Bioderived Chitosan Blend Films with Banana and Potato Extract

Plastic waste and food waste are two major environmental issues that have been severely impacting their receiving environments. Single-use packaging materials are one of the main contributors to the plastic waste problem. Using food waste as starting materials for producing single-use packaging films can contribute to solving both environmental issues simultaneously. In this study, bioderived polymer films were produced using bananas, potatoes, and chitosan as feedstock materials. The physicochemical properties of both the extract slurry films and composite blend films were evaluated. The addition of chitosan in banana composite films increased the max stress by 260% and max elongation by 43% relative to the banana extract slurry films using solely banana extract as the film-forming material. Similarly, the addition of chitosan increased the max stress by 173% and max elongation by 62%, relative to films using only potato extract as the film-forming material. With a poly(3-hydroxybutyrate) lamination layer of 21 μm, the water vapor barrier properties of these blend films were improved by 85% without severe detriments to the film elasticity. X-ray diffraction analysis indicated a highly amorphous nature of the chitosan-extract composite films relative to the semicrystalline banana and potato extract slurry films. The addition of chitosan as film-forming material and use of poly(3-hydroxybutyrate) as a lamination barrier layer is a promising strategy to improve both the strength and elongation of polymer films generated from food waste materials. Considering the mechanical and water vapor properties of the laminated films, potato-based films exhibited the best performance.

The use of a coating layer of biodegradable polyester poly(3-hydroxybutyrate) as a barrier significantly improved the water vapor barrier properties of food waste-derived blend films by 85%. These bilayer composite films also demonstrated excellent transparency.