Poly(lactic acid) formulations with improved toughness by physical blending with thermoplastic starch

Abstract

[EN] This work focuses on poly(lactic acid) (PLA) formulations with improved toughness by physical blending with thermoplastic maize starch (TPS) plasticized with aliphatic¿aromatic copolyester up to 30 wt %. A noticeable increase in toughness is observed, due to the finely dispersed spherical TPS domains in the PLA matrix. It is worth to note the remarkable increase in the elongation at break that changes from 7% (neat PLA) up to 21.5% for PLA with 30 wt % TPS. The impact-absorbed energy is markedly improved from the relatively low values of neat PLA (1.6 J/m2) up to more than three times. Although TPS is less thermally stable than PLA due to its plasticizer content, in general, PLA/TPS blends offer good balanced thermal stability. The morphology reveals high immiscibility in PLA/TPS blends, with TPS-rich domains with an average size of 1 micrometre, finely dispersed which, in turn, is responsible for the improved toughness.