Antioxidant activity of mango seed wax additive on the properties of poly(lactic acid) transparent films for food packaging application
Mango seed wax, one of the agricultural wastes can be effectively used as a plasticizer for poly(lactic acid) (PLA). The presence of antioxidant properties for mango seed wax is an advantage for PLA when used as a food packaging material.To improve the tensile properties of poly(lactic acid) (PLA) biodegradable packaging film, mango seed wax (MSW), an agro?industrial waste from the mango fruit processing industry has been used as a plasticizing additive. Four different weight ratios of MSW (3, 5, 7, and 9 wt%) in pristine PLA were considered for optimization. The mechanical properties comprising tensile strength, elongation at break, and Young's modulus were studied. Characterizations such as Fourier transform infra?red (FTIR) spectroscopy, and differential scanning calorimetry were studied. Oxidation induction time (OIT) analysis of samples was also conducted. Other studies such as thermal, barrier, and optical properties were also evaluated. The differential scanning calorimetry (DSC) analysis revealed better compatibility between MSW and PLA matrices. A small decrease in glass transition temperature (10%), and melting point (3%) was observed when increasing the percentage of MSW in PLA. Moreover, the visual transparency of MSW/PLA systems was intact when increasing the loading. The addition of 9% MSW results in a 700% enhancement in elongation at break than that of pristine PLA. The optimized sample (PLA with 5% MSW) showed a 26% improvement in the hydrophobicity of the PLA matrix. The barrier properties (55.6% in WVTR and 10% in oxygen transmission rate (OTR) were also improved by the presence of MSW. These are promising systems as a suitable material for biodegradable food packaging thermoplastic material.