Apparently, pure PLA has a strong strain softening which, however, is not stabilized by a strain hardening. Upon drawing, strain softening stimulates strain localization
which causes the build-up of local tri-axial stresses. If the local strain could not be delocalized, this local tri-axial stresses will induce void nucleation and crazes in the
matrix leading to a brittle failure behavior [40,41]. For this reason, PLA is brittle. Under tensile conditions, all the examined PLA/EVA50 blends show strain softening followed by stable neck growth and strain hardening, which explains the ductility of PLA/EVA50 blends. It is worth noting that only 5 wt.% EVA50 could make PLA already ductile (eb 300%) without obviously compromising on stiffness and strength of the PLA.