Modified starch / poly(butylene adipate-co-terephthalate) films: The role of processing technologies in achieving high-starch-content and high-performance.

Interfacial compatibilization and optimization of processing technologies have long been effective strategies to enhance the properties of composite materials. In this study, to achieve a robust interfacial compatibility of modified starch and Poly(butylene adipate-co-terephthalate) (PBAT) and to enable the continuous film blowing of high-starch-content films, this study systematically investigated the effects of different processing technologies on the processability of high-starch-content modified starch (MS)/PBAT composites for blowing based on modifying starch with polyurethane prepolymer (PUP). Furthermore, high-starch-content MS/PBAT films were blown from corresponding MS/PBAT composites using a single-screw blown film machine. The mechanical properties, thermal stability, rheological properties and other properties of MS/PBAT composites and films were compared to identify the optimal technology. Results demonstrated that the composite film subjected to film blowing after 15 min of internal mixing followed by extrusion possessed the best performance, with a tensile strength of 10.5 MPa, excellent processability, and thermal stability. The main reason is that the ingenious combination of an internal mixer and a twin-screw extruder solves the problems encountered during their individual use. Notably, when the modified starch content reached 60 %, the tensile strength of the film exceeded 7.09 MPa, satisfying market requirements while significantly reducing production costs. This study provides multi-dimensional references and insights for the extensive application of biodegradable polymers in high-performance, cost-effective, biodegradable and environmentally friendly composite films.