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 degrees C, 100 degrees C, 120 degrees C and 140 degrees 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 (similar to 20 kJ m(-2)), and thus it is very promising for technical applications.