Vijay Mohan Shetty ,M. Madhavi, P. Ramesh Babu 02 07 This study investigates the synergistic effects of alkali posttreatment and fiber orientation on the impact behavior of woven flax fiberreinforced epoxy laminates Six distinct layup configurations were fabricated using the hand layup technique Postcuring the laminates were chemically treated with 5 and 10 sodium hydroxide NaOH to enhance fibermatrix interfacial bonding Mechanical performance under impact loading was assessed through drop weight lowvelocity impact and quasistatic indentation QSI tests at impact energies of 5 J 10 J and 15 J The 5 NaOHtreated composites exhibited superior energy absorption across all layups with maximum QSI absorption efficiency reaching 787 in symmetric hybrid D and 786 in group hybrid E configurations at 15 J Angleply F and hybrid stacking C configurations also demonstrated comparable resistance 783784 These improvements were attributed to enhanced fibermatrix adhesion and favorable inplane load distribution enabled by the multiangled orientations In contrast the 10 NaOH treatment while improving bonding led to marginal fiber degradation slightly reducing energy absorption efficiency typically 757759 Unidirectional stacks A consistently showed the lowest performance due to directional stress concentration and limited delamination control The results underscore the importance of optimizing both chemical surface modification and laminate architecture to achieve highimpact resistance in natural fiber composites This study provides a pathway for developing sustainable lightweight and structurally resilient materials for automotive and aerospace applications where energy absorption and ecoefficiency are critical Copyright (c) Journal of Science Engineering Technology and Management Science. All rights reserved 2026