Optimization and characterization of degradable bioplastic derived from banana peels and eggshells: towards sustainable alternatives

The rise in public attention to plastic pollution worldwide and the drive towards sustainable alternatives has led to bioplastics being explored as a possible solution. Using eggshells and banana peels as raw materials, this study examined the effects of drying temperatures, glycerol concentrations, and the ratio of banana to eggshell throughout the hydrolysis process to produce bioplastic. The impacts of drying temperatures (50, 60, and 70 °C), glycerol concentrations (4, 8, and 12% w/w), and the ratio of banana peels to eggshells (1, 2, and 3) were analyzed and optimized using the design of experiment (DOE) for response surface methodology (RSM). The maximum tensile strength, elongation at a break, and degradability rates were 11.15 MPa, 6.57%, and 44.75%, respectively. The lower water absorption was 65.76%. At optimal conditions of 57.99 °C temperature, 9.02% w/w of glycerol concentrations, and 1.17 banana to eggshell ratio for hydrolysis, good quality of bioplastic with 10.82 MPa of tensile strength, 6.11% elongation at break, 67.49% water absorption, and 44.75% degradability was produced. O–H (3413 cm⁻¹), C-H (2925 and 2854 cm⁻¹), C–O (1741.2 and 1637.8 cm⁻¹), C–H symmetric deformation (1384.6 cm⁻¹), and C-O–H groups were indicated in the bioplastic film using FT-IR analysis.