Toughening Behavior of Poly(L-Lactic Acid)/Poly(D-Lactic Acid) Asymmetric Blends

The L-configured poly(lactic acid) has exhibited vast appeal in the past decades. However, most previous researches reveal that L-configured poly(lactic acid) exhibits fragile behavior, which limits its applications. Present work clarified that the toughness of poly(lactic acid) depended on the content of crystallites and rigid component incorporated into the specimens. The elongation at break was remarkably high in the L-configured poly(lactic acid)/D-configured poly(lactic acid) with a small amount of D-configured poly(lactic acid) (≤15%). The stretching led to orientation of crystals and amorphous molecular chains and segments. The crystals did not vary, while the amorphous molecular chains transited to mesophase during stretching, and this mesophase formed homocrystallites during heating.