Mechanical and tribological characteristics of screw pine fiber reinforced natural rubber composites

Natural rubber (NR)- screw pine fiber-reinforced composite was synthesized in the laboratory using a two-roll mixing mill with fiber length (5 mm, 10 mm, 15 mm, and 20 mm) and fiber concentration (0, 10, 20, and 30 phr) as the major variables. The mechanical characteristics such as tensile strength, elongation at break, hardness and compression set and tribological properties mainly coefficient of friction was studied in detail as a function of fiber length and fiber loading. Tensile fracture surface morphology and worn surface morphology were analyzed by scanning electron microscopy. The tensile and tear strength were highest with 15 mm fiber length, allowing effective transfer of stress from the fiber to the rubber matrix. Fiber lengths greater than 15 mm, however, resulted in entanglement and decreased reinforcement efficiency. Tribological studies revealed the lowest coefficient of friction (COF) and specific wear rate for composites with 20 mm fibers. These findings suggest that screw pine fiber effectively reinforces NR composite, enhancing its strength and durability. The product synthesized with an optimized composition indicates a potential for use in moderate-load, eco-conscious rubber products, where basic mechanical and wear resistance are required.