Synthesis, Thermal, and Chemical Characterization of Durian Peel Starch-Based Bioplastic with Sorbitol Plasticizer and Chitosan or Zinc Oxide Filler Variations

Abstract

Plastic waste poses significant environmental challenges due to its persistence. Durian peel waste, which contains starch and lignocellulosic components, has potential as a renewable raw material for biodegradable bioplastics. This study aimed to evaluate the chemical characteristics and thermal stability of durian peel starch-based bioplastics containing chitosan or zinc oxide (ZnO) fillers at different tapioca starch–durian peel starch ratios. Bioplastics were prepared by blending and casting using tapioca starch and durian peel starch ratios of 1:1, 1:0.75, and 1:0.5, with sorbitol as a plasticizer and either chitosan or ZnO as fillers. Chemical characteristics were analyzed using FTIR, while TGA-DTA was used to evaluate thermal behavior. FTIR spectra showed the characteristic functional groups of the constituent materials, with no new absorption bands, indicating that the bioplastics were formed primarily through physical interactions and hydrogen bonding. Thermal analysis demonstrated that increasing durian peel content improved thermal stability. The highest residue yields were obtained for sample C, containing chitosan (22.976%), and sample F, containing ZnO (23.706%), at a tapioca starch-durian peel starch ratio of 1:0.5, indicating superior resistance to thermal degradation. The incorporation of durian peel lignocellulosic components together with chitosan or ZnO fillers enhanced the thermal stability of starch-based bioplastics. Among the formulations tested, the 1:0.5 tapioca starch–durian peel starch ratio exhibited the best thermal performance, demonstrating the potential of durian peel waste as a sustainable raw material for biodegradable packaging applications.