<![CDATA[Driven by rapid technological advancements, material trends have increasingly shifted toward Natural Composites (NACO), primarily owing to their renewability and recyclability. Nevertheless, the utilization of natural resins such as rosin (gondorukem) as a matrix frequently yields brittle characteristics, necessitating the incorporation of plasticizers to enhance their mechanical properties. Despite this, the specific influence of varying plasticizer concentrations on the physical stability, underlying fracture mechanisms, and macro and microstructural properties of rosin ramie composites remains largely unexplored. This study aims to engineer and evaluate the effect of plasticizer concentration (15% and 30%) on the impact toughness, absorbed energy, and structural characteristics of rosin matrix ramie fiber composites. An experimental approach was employed using ASTM D256 standard for impact testing, coupled with macro and microstructural morphological analyses. The findings indicate that the maximum average impact toughness reached 0.0735 J/mm² at a 30% plasticizer concentration. Interestingly, the maximum single absorbed energy of 9.880 J was observed at 15% concentration, yielding a specific impact value of 0.0689 J/mm². This discrepancy occurs because the 30% plasticizer provides a more uniform plastic deformation capability across samples, whereas the 15% concentration exhibits localized rigid resistance before catastrophic failure. Morphological analyses revealed fracture mechanisms including fiber pull out, matrix cracking, and oxidation, which correlate directly with the mechanical performance. Altering the plasticizer concentration significantly influences the polymer chain mobility and interfacial bonding of the composites. The 30% concentration optimally prevents micro crack propagation, offering significant practical value for developing sustainable, impact resistant green engineering materials.]]>
