Toughening of poly (lactic acid) by poly (β-hydroxybutyrate-co-β-hydroxyvalerate) with high β-hydroxyvalerate content

► PLA was effectively toughened without compromising its bio-based and biocompostable feature. ► PHBV with high HV content (40 wt%) was first time reported as a toughening modifier for PLA. ► Crystallization is suppressed in confined domains of finely dispersed PHBV phase due to the lack of nuclei. ► The structure-property relationship of the PLA/PHBV blends was well established. ► The toughening mechanism was revealed based on the analysis of the local deformation.