Evaluate the mechanical characteristics of hybrid natural fiber composites comprising ramie and flax under various conditions

The study focused on utilizing a hybrid ramie/flax natural fiber reinforcement in conjunction with epoxy resin as the matrix material. The fabrication method employed was compression molding. Among various combinations tested, the hybrid composition with 40 wt.% of 1 cm fiber length exhibited superior tensile strength at 32.67 MPa. Optimal compatibility between fiber/matrix phases and improved stress transfer behavior, as well as enhanced elastic deformation, were achieved with hybrid fiber combinations ranging from 30 to 40 wt.%. The addition of fibers, varying in length up to 40 wt.% and 0.5 cm, led to a significant improvement in flexural strength, increasing from 43.75 to 52.47 MPa. Moreover, the impact strength of the hybrid combinations also saw a notable enhancement, ranging from 10.23 to 15.97 kJ/m2. Notably, a 5% NaOH treatment had a substantial impact on tensile properties, ranging from 28.42 to 32.67 MPa, surpassing both untreated and 8% surface-treated fibers. Alkali treatment resulted in flexural strengths ranging from 49.83 to 52.47 MPa and 49.12 to 49.99 MPa. The study identified that the maximum tensile strength of 33.46 MPa was achieved under specific conditions, namely 120°C temperature, 12 MPa pressure, and 7 minutes duration. It was observed that excessively high pressure, elevated operating temperatures, and prolonged processing times led to a decline in the mechanical properties of the polymer composites. SEM analysis further corroborated these findings, indicating that the hybrid composition with 40 wt.% natural fiber exhibited superior fiber distribution, thereby contributing to the overall improved properties. It is worth noting that research efforts in the domain of natural fiber incorporation, fabrication conditions, and surface treatments are scarce, making this study a valuable contribution to the field.