Vijay Mohan Shetty ,M. Madhavi, P. Ramesh Babu 02 07 Natural fibers particularly flax are recognized as an ecofriendly alternative to synthetic fibers in composite materials Their use is growing due to their low cost biodegradability and sustainability This study investigates the effect of alkali treatment on the loadbearing capacity of natural flax fiber epoxy composites Flax fibers were treated with 5 and 10 NaOH solutions to enhance the fibermatrix interaction and the composites were fabricated using the hand layup technique with an epoxy resin matrix A series of mechanical tests were conducted including lowvelocity impact drop weight tests quasistatic indentation and water absorption tests The results demonstrated a significant improvement in the loadbearing capacity of the alkalitreated composites particularly in lowvelocity impact and indentation resistance with 10 NaOHtreated fibers exhibiting the highest performance Alkali treatment enhanced the interfacial bonding between the flax fibers and epoxy resin leading to better stress transfer and increased energy absorption during impact However the water absorption test showed a slight reduction in moisture uptake suggesting that alkali treatment improves the composites moisture resistance Despite the enhanced performance higher NaOH concentrations 10 caused slight fiber degradation affecting the elongation at break Overall the findings suggest that alkali treatment effectively improves the mechanical properties and durability of flax fiber composites making them suitable for highperformance ecofriendly applications provided that the NaOH concentration is optimized Copyright (c) Journal of Science Engineering Technology and Management Science. All rights reserved 2026