In the EAC-toughened PLA blends [22], the authors attributed the toughness of the PLA/EAC blends to a combination of different deformation mechanisms, i.e. crazing, crack bridging, interfacial debonding and matrix shear yielding, without discussing the dominating mechanism. For the PLA/PBS [14], PLA/PBAT [16] and PLA/poly(ethylene- co-octene) blends [19], the proposed toughening mechanisms were interfacial debonding and matrix yielding, all based on SEM observations of fracture surfaces. The mode of microscopic deformation in the outer plastic zone was not discussed.