Effect of polyvinyl alcohol on the physicochemical properties of biodegradable starch films.

Biodegradable films based on starches have poor mechanical and barrier properties, limiting their applications as a food packaging material. The combination of two or more polymers allows obtaining new materials with better functional properties. Mixtures at different proportions (0?60%) of polyvinyl alcohol (PVOH) were studied and the effect on water adsorption, water vapor permeability (WVP), mechanical (percentage of elongation at break and tensile strength) and thermal (Tg) properties was evaluated. In all the formulations, both polymers showed a good compatibility during processing and in the resulting material. The addition of PVOH significantly favored the functional properties, improved the gas permeability and the mechanical properties of potato starch films. The formulation containing 60% PVOH (S4P6) showed the best barrier to water vapor, lower density and solubility as well as better mechanical performance. PVOH resulted in potato starch films with suitable properties for possible applications in food packaging and as a biodegradable alternative for the replacement of synthetic packaging materials.