Physical, thermal, morphological, and tensile properties of cornstarch-based films as affected by different plasticizers

The current research was designed to determine the effect of various concentrations (0%, 25%, 40%, and 55%) of fructose, sorbitol and urea plasticizers in cornstarch-based films, with the aim of achieving a new polymer for the application of biodegradable materials. Casting technique was used to prepare the films. The physical, morphological, thermal, and mechanical properties of produced films were evaluated. The results showed that the thickness, moisture content, and water solubility increased with the addition of plasticizer concentration. While the glass transition temperatures showed an insignificant effect with high plasticizer content. Regardless of plasticizer sort, the tensile stress and Young's modulus of plasticized films decreased as the plasticizer concentrations were raised beyond 25%. Likewise, the relative crystallinity decreased by increasing the plasticizer content from 0% to 25%, but it began to grow once the concentration increased above 25%. The fructose-plasticized films presented consistent and more coherent surfaces compared to sorbitol and urea counterparts, which appeared less homogeneous surfaces with microcracks. In summary, the plasticizers types and concentrations are affected significantly on the properties and performance of the cornstarch-based film. Film plasticized with 25% fructose appeared the finest set of features and achieved the highest mechanical performance among the plasticizers used in this study.