Preparation and characterization of the Leonardite and Boric acid added Polylactic acid films for food packaging applications

Polylactic acid (PLA), a biodegradable plastic, has begun to replace petroleum-based plastics used in thin film. According to the literature, various clays are used to develop PLA matrix film. In this study, PLA composite films containing specific proportions of Leonardite (LEO) and Boric acid (BOR) were prepared by casting method, and the physical, mechanical, thermal, barrier, and microstructure properties of these films were studied. As the amount of LEO in LEO and BOR/LEO added films increased, correspondingly increased the TS and EM values, while TR and MF values decreased, and the EB values fluctuated. As the amount of BOR increases in BOR added films, the increases and decreases in TS and EM values are similar, while the TR, MF and EB values decrease. In added films, the additive effect is clearly seen in the XRD patterns. While the addition of LEO significantly changed the surface color and opacity, BOR added films showed fewer changes in these properties. The Contact angle measurements demonstrated that, while the addition of BOR reduced the CA value, the addition of LEO partially increased it. The addition of BOR/LEO resulted in an increase in CA value because of the effects of LEO.