Avocado seed, coconut fiber, and vinegar residue blended composite biodegradable bioplastic film development: Agricultural waste management approach

Abstract

Traditional plastics are deeply embedded in modern life because of their convenience and affordability. However, their extensive use has resulted in significant environmental issues. To that end, biodegradable bioplastics, fabricated from natural sources containing starch and cellulose, offer a promising solution. Therefore, this present work utilized agricultural wastes, including starch extracted from avocado seed, microcrystalline cellulose (MCC) obtained from coconut fibers, and vinegar residue as binder and plasticizer, to produce biodegradable bioplastics, by the simple one-pot mixing process. The avocado seed contained 18% starch, and the 100-mesh starch consisted of amylose (0.089%), amylopectin (74.43%), water (21.47%), ash (0.25%), protein (1.98%), and lipid (1.68%). The optimal bioplastic formula comprised 10 g of avocado seed starch, 1 g of bentonite, 3 g of vinegar residue, 4 g of coconut fiber MCC, 5 mL of glycerol, and 50 mL of water. The resulting bioplastic film exhibited a tensile strength of 27.92 MPa, an elongation at a break of 23.68%, nano-sized crystallites of 18.47 nm, a smooth surface with transparency of 91 ± 3%, high water vapor transmission rates of 157.3 to 219.6 g/m²day, and modifiable chemical functional groups. These bioplastic films also exhibited excellent biodegradability, with complete degradations after 13 days, 38 days, and 100 days, in alkaline, acidic, salt, and soil conditions, respectively. In a nutshell, by using agricultural wastes, this research successfully formulated natural biodegradable bioplastics, consequently addressing the plastic pollution crisis and contributing to sustainable waste management practices and the development of economically feasible bioplastics.