Starch Maleate/Epoxidized Soybean Oil/Polylactic Acid Films with Improved Ductility and Biodegradation Potential for Packaging Fatty Foods

Abstract

The commercial marketability of polylactic acid (PLA) food packaging films is limited by their poor ductility and biodegradation ability. To address these challenges, a high-DS amylose-rich corn starch maleate (SM)/epoxidized soybean oil (ESO)/PLA composite film was developed. The film demonstrated significant ductility improvement (elongation at break increased from ≈3.63 to 36.75% while the tensile toughness improved 15-fold compared to the neat PLA film) because of improved interfacial interactions and mobility of ESO-plasticized PLA chains. Furthermore, due to absence of voids, the SM/ESO/PLA film also outperformed the ESO/PLA film in terms of oxygen (23,140 cm3 μm m–2 day–1 Pa–1) and water vapor (0.03 × 10–5 g m–1 day–1 Pa–1) barrier performances. These characteristics, together with findings that the SM/ESO/PLA film could rapidly breakdown in saline water (2.92 wt % per day) and compost (the C/N ratio increased from 20.4 to 22.69), as well as absence of ESO migration in fatty food simulants, make the SM/ESO/PLA film a promising material for food packaging.

Grafting Polymerization of Long-Chain Hydrophobic Acrylic Monomer onto Lignin and Its Application in Poly(Lactic Acid)-Based Wholly Green UV Barrier Composite Films

“…PLA can be processed conveniently by injection molding, film blow molding, and other commercial methods in a temperature range of 170–230 °C . Therefore, PLA is widely used in many fields, such as 3D printing, , food packaging, , biomedical field, , adhesives, , and so forth. However, the rigidity of the main chain structure of PLA determines the brittleness and low elongation at break (4–6%), which limits its application in a wide range of fields.…”

Polylactic acid/epoxidized linseed oil/polypropylene grafted maleic anhydride: A promising combination of toughness and rigidity

“…The addition of 1 and 5 wt% of ELO, as well as the presence of 3 and 5 wt% of PPgMA resulted in significant improvement of this property, indicating that both ELO and PPgMA individually were able to improve the impact resistance of PLA, and this feature was also observed in the toughness response. These characteristics were reported for PLA-based systems containing epoxydized oil 9,16 and also PPgMA, 23 which were attributed to the reaction between the functional groups of each component and the PLA at the interface. Samples containing PPgMA/ELO = 3:1 and 5:1 wt% also presented significant improvement of this property and the best response was achieved by using PPgMA/ELO = 5:5 wt%.…”

“…To avoid such drawbacks, some reports added other special fillers or additives to provide covalent interaction between oil and PLA. For example, Goswami et al 16 used small amount of starch maleate (SM) to improve compatibilization of epoxidized soybean oil (ESBO) and PLA. The blend containing PLA/ESBO/SM in a proportion of 93:5:2 wt% resulted in significant improvement of elongation at break without affecting tensile strength.…”

The Potential of Bio-Based Polylactic Acid (PLA) as an Alternative in Reusable Food Containers: A Review

“…The PLA-cinnamate ester composites were processed by injection moulding. The T g of the resulting composites was, however, reduced from 61.7 • C to 36.1 • C. Biocomposites of corn starch maleate and epoxidized soybean oil (2:5 wt.%) were used to increase the elongation at break of PLA film (93 wt.%) from 3.63% to 36.75% [109]. The resulting composite was fully biodegradable within four weeks.…”