Effect of Green Plasticizer on the Performance of Microcrystalline Cellulose/Polylactic Acid Biocomposites

In this study, we present the development of eco-friendly biocomposites composed of polylactic acid (PLA) and microcrystalline cellulose (MCC), using melt extrusion and compression molding processes. In all the studied samples, the PLA/MCC ratio was always 1:1, whereas the plasticizer triethyl citrate (TEC) was responsible for the improved dispersion of the MCC in PLA. Tensile tests proved that the developed biocomposites containing TEC show improved ductility and crystallinity, as confirmed by the X-ray diffraction (XRD) study. Furthermore, the water vapor and oxygen permeability of the biocomposites were found to decrease as the TEC content increases in the formulation. Nonetheless, migration analyses to a dry food simulant prove that the migration of TEC is slightly above the acceptable limits when biocomposites with 15 wt % TEC were used. Taking this into account, in combination with the ranking of all the developed biocomposites according to their performance through the technique for order of preference by similarity to ideal solution (TOPSIS) analysis, we concluded that the PLA/MCC samples with 10 wt % TEC can be considered the most suitable biocomposites for eco-friendly food packaging applications. These findings place the developed PLA/MCC biocomposites among the strong candidates for biobased food packaging materials able to be produced at a large scale following industrially applicable methods since they are cost-effective and have improved properties compared to the pure biopolymer.