LAUSR

Natural fiber‐reinforced biocomposites are emerging as viable alternatives to conventional thermoplastics; however, low mechanical and physical properties limit their broad applications. This study addresses these limitations by developing a nanoclay and cashew nut shell liquid (CNSL)‐modified novel soy resin‐based jute composites by enhancing mechanical and physical performance. CNSL, rich in phenolic compounds, chemically interacts with the soy matrix, improving interfacial bonding and imparting resistance to environmental degradation. Nanoclay dispersion within the matrix optimizes load transfer, as confirmed through density functional theory (DFT) calculations of interaction energies, resulting in a synergistic effect on composite strength. The optimized composite exhibited a remarkable storage modulus of 8697 MPa at 35°C and 1 Hz, a flexural modulus of 3288 MPa, tensile strength of 61.3 MPa, and flexural strength of 62.7 MPa. X‐ray diffraction and transmission electron microscopy analyses revealed a well‐integrated nano‐biocomposite structure, confirming successful reinforcement dispersion. Thermal stability up to 290°C, a contact angle of 61.4°, and water absorption of 49.5% indicate its suitability for diverse conditions. Additionally, cytotoxicity tests demonstrated the material's biocompatibility, while soil burial tests showed a mass loss of 74.2% over 75 days, verifying its biodegradability. These biocomposites can replace nondegradable thermoplastics in various applications.