Mechanical properties of ramie/flax hybrid natural fiber composites under different conditions

Hybrid ramie/flax natural fiber reinforcement along with epoxy resin is used as the matrix material in this research. Compression molding was adopted as the fabrication method. Ramie/flax at 40 wt. % and 1 cm fiber length showed a better tensile strength of 32.67 MPa than other combinations. Hybrid fiber combination from 30 to 40 wt. % created a strong compatibility between fiber/matrix phase and improved stress transfer behavior along with elastic deformation. Flexural strength results showed enhancement from 43.75 to 52.47 MPa with fiber addition and varying fiber length up to 40 wt. % and 0.5 cm. Impact strength of the hybrid combinations increased from 10.23 to 15.97 kJ/m(2). A 5 % NaOH treatment had significant tensile properties varying from 28.42 to 32.67 MPa compared to untreated and 8 % surface treated fibers. Alkali treatment a revealed 49.83-52.47 MPa and 49.12-49.99 MPa flexural strength. Maximum tensile strength of 33.46 MPa was observed under a combination of 120 degrees C temperature, 12 MPa pressure, and 7 min duration. High pressure, high operating temperature and time, lead to a decline in the mechanical properties of the polymer composites. The SEM analysis showed that the combination with 40 wt. % natural fiber had good fiber distribution leading to better properties. Research works dealing with natural fiber addition, fabrication conditions, and surface treatments are rare.