Simultaneous Enhancement of Ductility and Impact Toughness in Biodegradable <scp>PLA</scp> / <scp>PCL</scp> Blends via a Plasticizer Strategy

ABSTRACT Although blending brittle polylactide (PLA) with flexible poly(ε‐caprolactone) (PCL) holds promise for developing biodegradable materials with tunable mechanical properties, their poor compatibility poses a significant challenge to effective toughening. In this study, PLA/PCL blends with varying Dibutyl itaconate (DBI) content were prepared via melt blending, and the effects of DBI loading on the properties of the blends were systematically investigated. The results demonstrated that the incorporation of DBI enhanced the intermolecular interactions between PLA and PCL chains, thereby improving their compatibility. The phase interface between the PLA matrix and the PCL dispersed phase became so progressively blurred with increasing DBI content that it was nearly indistinguishable at a loading of 7 phr, demonstrating a significant improvement in compatibility. With the increase in DBI content, both the elongation at break and impact strength of the blends exhibited a trend of initial increase followed by a decrease. At the optimal loading, the maximum values reached 314.3% and 29.5 kJ/m 2 , representing enhancements of 3.4‐fold and 4.9‐fold, respectively, compared to those of the neat PLA/PCL blend. Simultaneously, the crystallization rate and enzymatic degradation rate of the blends increased continuously with higher DBI content. This study opens a new avenue for developing high‐toughness PLA‐based blend materials without compromising their biodegradability.