Influence of Ultrasonication Treatment on Mechanical, Optical, and Physiochemical Properties of Polyvinyl-alcohol/cornstarch Biocomposite Thin Films

Over the past few decades, Polyvinyl-alcohol (PVOH)/cornstarch (CS)-based composite thin films have garnered significant interest due to their enhanced properties. Synthesis of such films relies heavily on depolymerization reactions within the solution of the PVOH/CS blends. Understanding how depolymerization affects the crystal structure and properties of these films is crucial for further improvement. This study aims to evaluate the depolymerization effects of crosslinked PVOH incorporated with CS as filler materials (with an 80:20 mass ratio) using ultrasonication at various time intervals while maintaining a constant frequency of 25 KHz. The prepared solution is then cast into thin films using blade coating. Comparative analyses were then conducted between samples subjected to ultrasonication (treated) and without ultrasonication (untreated) to assess their properties based on structural physical, mechanical, optical, and aspects of biodegradability . The investigation revealed significant changes in crystal structure and lattice strains following ultrasonication of the PVOH/CS solution when compared to untreated PVOH/CS samples. Importantly, longer ultrasonication times correlated with increased tensile strength. Additionally, the treated samples led to improvements in thin film transparency and a notable decrease in absorbance. These changes were attributed to the mechanical depolymerization induced by ultrasonication, aligning the thin films with the necessary properties for food packaging applications.