Characterization study on the bio-composite with rice husk cellulose as reinforcement filler

Abstract The increasing demand for sustainable and environmentally friendly materials has driven the exploration of organic fibre as reinforcements, substituting the synthetic fibre in polymer composite. Among various agricultural wastes, rice husk is abundantly available and rich in cellulose, making it a promising candidate to improve the physical, mechanical, chemical and rheological properties of the polymer composite. This study investigates the mechanical and water absorption properties of epoxy resin composites reinforced with rice husk cellulose (filler). The composites were prepared with varying filler contents (0%, 2%, 4%, 6%, 8%, 10%, and 15%) and tested in accordance with ASTM D638 for tensile strength. Water absorption tests were also conducted to investigate the barrier properties of the composites. The results showed that tensile strength decreased at low filler loadings (2–4 wt%), then increased significantly from 6 wt% to a peak at 10 wt%, before declining at 15 wt%, likely due to particle agglomeration and reduced filler–matrix adhesion. In terms of water absorption, no consistent trend was observed across the different filler concentration. However, all composites with rice husk filler addition showed lower water uptake as compared to the control sample (0% filler), except for the composite with 15% filler, which showed a slight increase. These results suggest that moderate filler loading can enhance the hydrophobicity of the composite, but excessive filler may disrupt the matrix structure and compromise barrier performance. Overall, the findings concluded that rice husk cellulose can be used as an effective functional filler, enhancing both mechanical and moisture resistance properties of epoxy composites. This highlights its potential as a sustainable alternative to fossil-based fibres, supporting agricultural waste valorization in composite manufacturing.