Enhancement of Polylactic Acid Packaging Sheet by Adding Three Bio-composites and Evaluating them as Bioplastic

The food packaging industry is searching biodegradable alternatives to traditional plastics, with Polylactic Acid (PLA), starch (S), and cellulose (C) emerging as eco-friendly options. However, PLA faces challenges such as brittleness, rigidity, and low elasticity, limiting its use. This study examined the effect of cassava starch (CS), Polyhydroxybutyrate (PHB), and amorphous cellulose (AC) as copolymers to improve PLA properties. Results showed that incorporation of 8% AC was the most effective treatment, increased tensile strength by 16.8% and Young’s modulus by 20.1%, while elongation at break was improved by 58.57%. Barrier properties: AC reduced oxygen permeability of PLA–film from 2.24 to 1.73 and water vapor permeability from 0.22 to 0.17 cm3.cm/m2.d.kpa. Thermal properties: The addition of AC increased PLA’s crystallinity from 1.7% to 13.3%, and thereby improving mechanical strength. Annealing treatment of PLA/AC composite film at 80℃ for 20 min increased crystallinity to 42%. Biodegradability: AC enhanced the water solubility of the composite, promoting biodegradability. In conclusion, presence of amorphous cellulose (AC) improves the mechanical, barrier, and biodegradability properties of PLA–films, making it a promising material for sustainable food packaging.