Production of Biopolymer Foams Based on Polylactic Acid Plasticized With Lactic Acid Oligomer

Abstract In our work, we modified polylactic acid biopolymer using oligomeric lactic acid. We have successfully plasticised polylactic acid compounds with 5, 10, 20 wt% oligomeric lactic acid using a liquid dosing system connected to a compounder extruder. The produced compounds were foamed with an exothermic chemical foaming agent. The density of the foams was measured and the fracture surfaces were examined by electron microscopy to assess the homogeneity of the cell structure. Based on this, we believe that the plasticising effect of oligomeric lactic acid is undeniable, but a processing temperature of 190 °C is not optimal for the foaming process. In the future, the production of biopolymer foam structures with a higher density reduction can be achieved by reducing and optimizing the foam processing temperature.