New Materials, Compounds and Applications

The accumulation of agricultural residues and non-biodegradable plastic waste is posing serious environmental challenges, underscoring the urgent need for sustainable recycling solutions. Rice husks, a common byproduct of rice milling and waste polystyrene, a widely used synthetic polymer, significantly contribute to global waste pollution. This study introduces a solvent-based method to convert these waste materials into high-performance polymer composites. The fabrication process uses a solvent mixture of acetone and toluene in a 2.5:1.0 ratio (v/v), with a polystyrene foam-to-solvent ratio of 1.0:2.3 (g/g) and incorporates rice husk as reinforcement, constituting 30 wt% of the total solid blend of polystyrene foam waste and rice husk. The chosen formulation ensures even filler dispersion and strong bonding between the bio-based reinforcement and the polymer matrix. Initial mechanical evaluations under both film-like and bulk-like tensile testing conditions indicate that incorporating rice husk improves the tensile performance of the composites, as reflected by increased tensile stress at failure, while preserving their lightweight characteristics and favorable thermal resistance. For thin, film-like composite sheets prepared with 50 g of EPS, ASTM D882 testing confirmed that the maximum tensile stress increased from approximately 0.91 MPa at 20% rice husk content to 1.40 MPa at 40% and the maximum tensile force rose from 34 N to 67 N. Meanwhile, elongation at break slightly declined from 0.61% to 0.49%. For thicker EPS-rice husk composites, fabricated with 200 g of EPS per sheet, the composite exhibited a tensile strength of 3.33 MPa, a modulus of elasticity of 859 MPa and an elongation at break of 0.40%. Additionally, a simple yet effective water-resistant treatment was developed by coating the material with a commercial SOTEC-POXY waterproof adhesive, expanding its potential applications. The final product provides a practical alternative for construction, packaging and related industries seeking sustainable materials within a circular economy.