Evaluation of the effects of organic acids on the properties of thermoplastic starch

The growing environmental concerns associated with synthetic polymers have driven the demand for biodegradable alternatives, such as thermoplastic starch (TPS). However, TPS often lacks the mechanical and thermal properties required for broader industrial applications. In this study, citric acid (CA), tartaric acid (TA), and succinic acid (SA) were employed as chemical modifiers to enhance the properties of TPS through extrusion processing. The objective was to understand the role of organic acids in modifying the structural, mechanical, and thermal characteristics of TPS. Infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analyses revealed changes in the starch chains, indicating esterification and cross-linking. Thermogravimetric analysis (TGA) and mechanical testing demonstrated improved thermal stability, increased rigidity, and enhanced flexibility depending on the acid concentration. The citric acid provided greater plasticizing effects, while tartaric and succinic acids contributed to increased cross-linking, improving the material’s overall performance. The results indicate that using organic acids provides a sustainable and effective approach to modifying the properties of thermoplastic starch (TPS), positioning it as a viable alternative to conventional fossil-based polymers, with potential for various industrial applications.