Evaluation of Starch‐Rice Husk Based Biodegradable Composite Films With Enhanced Mechanical, Thermal, and Flame Retardant Properties

ABSTRACT In this study, starch‐rice husk (RH) based composite films were fabricated by loading 10–40 wt% of rice husk into starch matrix and various properties were evaluated. Fourier transform infrared (FTIR) analysis showed interaction between starch and rice husk through hydrogen bonding, with 20 wt% rice husk loading (RH/ST‐02) exhibits greater hydroxyl shift toward lower wavenumber (3430 cm −1 ). The tensile strength (9.046 MPa) and Young's modulus (7.712 MPa) were found to be highest in RH/ST‐02. Thermogravimetric analysis (TGA) revealed improved thermal stability for RH/ST‐02, which also showed highest limiting oxygen index (LOI) of 32.49%, indicating enhanced flame‐retardant behavior. RH/ST‐02 also demonstrated the lowest water uptake and improved acid and alkali resistance, while scanning electron microscope (SEM) revealed a compact and homogeneous morphology. Soil burial studies confirmed the biodegradable nature of all composite films, with RH/ST‐02 showing almost 80% weight loss after 72 days. The findings revealed that RH/ST‐02 shows an optimum reinforcement level, beyond which excessive filler loading may disrupt matrix continuity and results in less homogeneous morphology, thereby affecting the overall properties of the film. The novelty of this work lies in the valorization of locally available rice husk agricultural waste as a reinforcing agent for starch‐based films.