The application of the synergistic effect between the crystal structure of poly(lactic acid) (PLA) and the presence of ethylene vinyl acetate copolymer (EVA) to produce highly ductile PLA/EVA blends

In this paper, we produced ethylene vinyl acetate copolymer (EVA)-filled poly(lactic acid) (PLA) blends by extrusion and injection moulding. We annealed the injection-moulded specimens at 80 °C, 100 °C, 120 °C and 140 °C to produce various crystal structures in PLA. Then we investigated the cross-effect between the crystal structure of PLA and the presence of EVA on the mechanical, impact, calorimetric, thermomechanical and heat deflection temperature properties of the blends. We found a synergistic toughening effect between the crystal structure of PLA that developed during annealing and the presence of dispersed EVA particles in the PLA matrix. The blend had a very high impact strength of over 65 kJ m−2, which is three times higher than the impact strength of acrylonitrile butadiene styrene copolymer (~ 20 kJ m−2), and thus it is very promising for technical applications.