New poly(lactic acid)-based nanocomposite films for food packaging applications

The strategies that have been developed to improve the utility of poly(lactic acid) (PLA) in packaging materials were examined. This study has focused on two potential solutions: the addition of a plasticizer and the use of nanoclays under optimal conditions. Triacetin (TA) as a plasticizer (10 and 20% by wt) and modified nanoclays (C30B and C20A) as reinforcing agents (1 and 3% by wt) were incorporated into the PLA matrix. The PLA-based films were prepared through solvent-casting method. The nanocomposite films] characteristics including tensile properties, moisture content (MC), water vapor permeability (WVP), swelling, stability, FTIR spectra, optical properties, thermogravimetric analysis (TGA), and X-ray diffraction (XRD) were investigated. The results demonstrated that both TA and nanoclays led to an increase in the elongation-at-break ( E ab ) and tensile strength (TS) of PLA films. In addition, the films with TA of 20% (by wt) showed the highest E ab (78.5%). By adding nanoclays, a decrease in WVP, stability, and light transmission, and an increase in MC, swelling, and opacity of the PLA-based films were observed. PLA films with 3% (by wt) of C20A and 10% (by wt) of TA contents showed the lowest WVP (1.06 × 10 –10 g/m.s Pa). Furthermore, the film containing 3% (by wt) of C30B and 20% (by wt) of TA displayed the highest MC (19.4%). XRD analysis approved that an intercalated conformation was created in the nanocomposites during the incorporation process. The TGA showed a slight improvement in thermal stability of the nanocomposite films compared to a neat PLA film. This study confirmed that the PLA-based films prepared by incorporating an optimal amount of TA and the nanoclays (C20A and C30B) into the PLA matrix are promising materials for food packaging applications. Graphical abstract