Preparation and characterization of ductile PLA/PEG blend films for eco-friendly flexible packaging application

Poly(lactic acid) (PLA) is the most common biodegradable polymer in the food packaging industry; however, its inherent brittleness limits its applicability. To overcome this limitation, we prepared PLA/poly(ethylene glycol) (PEG) blend films via solvent-free melt extrusion and investigated the effects of different molecular weights (MW) and concentrations of PEG on the thermal, mechanical, barrier, and morphological properties and transparency of the blend films. As the PEG concentration increased, the glass transition and cold crystallization temperatures of the PLA phase in the blend films decreased, i.e., crystallization improved. The tensile strength and elongation of the blend films increased at low PEG concentration, whereas tensile strength decreased and elongation increased at high PEG concentration, indicating an improvement in the ductility of PLA. The oxygen barrier property and transparency of the films improved at high PEG MW and concentration. These PLA/PEG blend films have potential applications as biodegradable flexible packaging materials.