Optimizing the performance of poly(lactic acid)/poly (butylene adipate-co-terephthalate) blends: Improved toughness,...

To overcome the limitations of poly(lactic acid) (PLA), such as poor toughness, high cost, and slow degradation, this study prepares PLA/PBAT/DBI blends via melt blending by introducing poly(butylene adipate-co-terephthalate) (PBAT) and a bio-based additive, dibutyl itaconate (DBI). DBI, a multifunctional small molecule exhibiting both plasticizing and compatibilizing capabilities, has found broad applicability across diverse fields. However, its compatibilization mechanism in polymer blend systems remains insufficiently studied. Experimental results demonstrate that DBI's reactive CC bonds chemically interact with PLA and PBAT chains, enhancing interfacial adhesion. With 12 phr DBI, the glass transition temperature difference (ΔT_g) decreased by 13.81 °C, while elongation at break and impact strength increased by 5.16 and 2.77 times, respectively. The Vicat softening point rose from 82.6 °C to 93.5 °C. DBI also promoted degradation, yielding a weight loss rate 2.2 times higher than the control. These results suggest DBI acts as a dual-function additive that effectively improves compatibility, flexibility, and degradability, offering a promising route to high-performance biodegradable PLA-based materials for packaging and film applications.