Special interface structure and properties for compatible packaging film from biodegradable poly (butylene adipate‐co‐terephthalate)/corn starch composite

Abstract Starch is an environmentally friendly, renewable, green resource and an ideal alternative to polymers from petroleum resources. The preparation of high‐performance poly (butylene adipate‐co‐terephthalate) (PBAT)/corn starch composite materials is of significant importance for saving production costs and expanding the application fields of PBAT plastics. This study employed novel processing techniques such as melt blending and injection molding to fabricate PBAT/corn starch composite materials with polyurethane prepolymer (PCLPU) as a compatibilizer. The impact of varying polyurethane prepolymer concentrations on the composite material's structure, mechanical properties, morphology, thermal behavior, and water absorption was scrutinized. Mechanical performance testing showed that compared to the composite material without PCLPU (P90CS10), adding 5% PCLPU can increase the material's elongation at break from 350.2% to 359.0% and the tensile strength from 12.9 to 19.8 MPa. Scanning electron microscopy, thermogravimetric analysis, and water absorption results indicate that the composite material with the addition of the PCLPU compatibilizer has better compatibility, thermal stability, and water resistance than P90CS10. Additionally, the prepared composite material could be successfully blown into a thin film, further enriching the application of the composite material. Highlights A special interface structure was prepared to increase the compatibility of the poly (butylene adipate‐co‐terephthalate)/corn starch composite. Both the strength and the flexibility of the composite were successfully improved. The processing method through which modification was conducted in the melt was convenient, green, and effective. The prepared composite material has potential application value, and the processing method of the composite material is easy to transfer to industrial production.