Physicochemical Properties of Composite Materials Based on Thermoplastic Yam Starch and Polylactic Acid Improved with the Addition of Epoxidized Sesame Oil

摘要

Biodegradable materials provide a primary function in preserving and protecting food products, helping to extend shelf life. The present work aims to elucidate the physicochemical properties of improved composite materials based on thermoplastic yam starch (TPS) and polylactic acid (PLA) using epoxidized sesame oil. Sesame oil was epoxidized through homogeneous catalysis with peroxyacetic acid. The content of oxirane oxygen, FTIR, humidity, density, iodine number, acidity index, acid number and reaction yield were determined. The treatment with the highest reaction yield was selected as a coupling agent in TPS and PLA blends. Films were obtained through extrusion and compression moulding. To characterize the films, moisture content, solubility, contact angle, and mechanical, barrier, structural, and thermal properties were determined. According to results, the epoxidation reaction yield for sesame oil was the best treatment reaching values of 58.38% in formulation ESO2. Regarding the films, the addition of the epoxidized oil was effective to improve the blend interface by increasing of the PLA-TPS molecular interactions. Thus, the epoxidized sesame oil has a coupling effect in the TPS-PLA blends being effective to improve the interface between such polymers.