A Novel Functional Compatibilization Strategy for Poly(lactic acid) and Poly(butylene adipate-co-butylene terephthalate) Blends to Achieve a Stable Co-continuous Structure and Excellent Antibacterial Performance

Blends of poly(lactic acid) (PLA) and poly(butylene adipate-co-butylene terephthalate) (PBAT) are currently the most widely studied biodegradable blends and have great potential to replace conventional polyolefin and polyester materials. However, PLA/PBAT blends still face the challenges of poor compatibility and antibacterial performance in the practice applications. In this study, antibacterial functional PLA/PBAT blends were fabricated using an alternative copolymer (PSM-D) composed of reactive maleic anhydride segments and imidazolium cations. The results revealed that PSM-D, with long alkyl chains, improved the compatibility, antibacterial properties, and mechanical properties of the PLA/PBAT blends. Under the optimized conditions, the elongation at break of PLA/PBAT blends was increased by 750%. Detailed analysis demonstrated that these outstanding improvements could be ascribed to the formation of a stable co-continuous structure in the PLA/PBAT matrix. Furthermore, the PLA/PBAT blends exhibited excellent antibacterial properties against both gram-positive Staphylococcus aureus and gram-negative Escherichia coli, which was attributed to the presence of imidazolium cations with long alkyl chains. This study provides a new "two-in-one" platform for fabricating functional compatibilization strategies for biodegradable polymer blends and is expected to have broad implications and practical relevance for packaging and medical devices.