Influence of Plasticizer Type on Starch-Based Nanocomposite Films Reinforced with CMC and ZnO

Abstract

The development of eco-friendly composite films from renewable resources represents a crucial strategy to reduce dependence on petroleum-based plastics. In this study, carboxymethyl cellulose (CMC) derived from oil palm empty fruit bunches (OPEFB) was utilized along with starch and zinc oxide nanoparticles (ZnO NPs) to fabricate biodegradable composite films. Two types of plasticizers, glycerol and sorbitol, were incorporated at varying concentrations of 20%, 30%, and 40% to evaluate their influence on the physical properties of the films, including density, thickness, moisture content, water absorption, and tensile strength. The results revealed that both plasticizers affected the structural and physical characteristics of the films. Sorbitol addition decreased density from 1.413 g/cm³ to 0.463 g/cm³ and increased moisture content and water absorption, whereas glycerol addition increased density from 1.330 g/cm³ to 1.559 g/cm³ and reduced moisture content and water absorption. The formulation containing 20% glycerol showed optimal results for higher density and water resistance, while 40% sorbitol provided superior performance with enhanced mechanical integrity and lower water sensitivity. Overall, the type and concentration of plasticizer play a critical role in determining the physical properties of OPEFB-derived CMC/starch/ZnO nanocomposite films, demonstrating their potential as environmentally friendly packaging materials to replace conventional plastics.