The use of mixture design in optimization of biodegradable three-component composite film formulation of starch, zein and PVA based on physicochemical and mechanical properties

Production and use of biodegradable films with appropriate physical and mechanical properties and replacing them with synthetic materials is an effective solution to reduce many environmental pollutions. In this study, with the aim of producing biodegradable consistent structure and durable composite films, starch, zein and PVA were mixed with different proportions according to mixture design and ternary composites were prepared.Physical and mechanical properties were compared and optimum formulation were determined. According to the results, adding PVA to starch improved the mechanical properties and adding zein to it reduced the water solubility of the composite films. The optimal formulation of the three-component composite was determined as 85% starch, 15% zein and 5% PVA with a desirability level equal to 98%.The x-ray diffraction patterns of optimal film showed two specified peak at 2θ = 17-19 ° and 2θ = 22-24°, this pattern indicated the amorphous and crystalline structure of the composite film. Finally, differential scanning calorimetry showed that the highest weight loss of composite film is 285/3-340°C equal to 48/2%.