Supertoughened biodegradable poly(L-lactic acid) by multiphase blends system: Crystallization, rheological and mechanical properties.

• PLA/PHBH/PVAc ternary blends were prepared by simply melt mixing. • PVAc was electively located in PLA matrix and refined phase morphology. • Addition of PHBH and PVAc increased the flexibility and toughness of PLA. • Melt viscoelasticity of PLA was improved by incorporation of PHBH and PVAc. To toughen brittle poly(L-lactic acid) (PLA), poly(3-hydroxybutyrate- co -3-hydroxyhexanoate) (PHBH) and poly(vinyl acetate) (PVAc) were introduced into PLA matrix to prepared PLA/PHBH/PVAc ternary blends. PVAc was electively located in PLA matrix and refined phase morphology owing to better miscibility of PVAc with PLA than with PHBH. Increase in PVAc content decreased the crystallization rate and the crystallinity of PLA due to the dilution effect. More importantly, prominent enhancement of flexibility and toughness of PLA was obtained by the addition of PHBH and PVAc. Elongation at the break and impact strength of ternary blend with 10 wt% PVAc were 277 % and 326 % higher than that of neat PLA. Melt viscoelasticity of PLA was improved by incorporation of PHBH and PVAc. The combination of increased toughness and high melt viscoelasticity established in PLA biodegradable blends represent properties required in a wider range of applications. [Display omitted] [ABSTRACT FROM AUTHOR]