Mechanical and tribological performance of NaOH-Treated bamboo fiber-reinforced recycled HDPE composites under fretting wear conditions

The study investigates the impact of bamboo fiber reinforcement on the mechanical and tribological properties of recycled high-density polyethylene (rHDPE) composites. Bamboo fibers extracted from locally sourced Bambusa Balcooa were subjected to a comprehensive alkali treatment to enhance their properties, including increased crystallinity, thermal stability, and altered morphology. The treated bamboo fibers were incorporated into rHDPE using a compression molding technique at varying weight percentages (0.5-2.0 wt-%). The results revealed that optimal mechanical performance, particularly tensile strength (155.7 MPa) and modulus (6.6 GPa), was achieved at 1.5 wt-% fiber content, attributed to effective load transfer between the matrix and fibers. Beyond this content, performance declined due to fiber agglomeration and poor dispersion. Flexural properties mirrored these findings, with the highest strength (207.5 MPa) and modulus (11.7 GPa) observed at 1.5 wt-%. Thermogravimetric analysis (TGA) and X-ray diffraction confirmed enhanced thermal stability and crystallinity in treated fibers. Fretting wear tests indicated a reduction in the coefficient of friction with increased fiber content, particularly at lower loads, while wear loss was minimized at 1.5 wt-% BF, suggesting optimal reinforcement. SEM analysis highlighted microstructural changes, including fiber pull-out, debonding, and void formation, correlating with the observed mechanical degradation at higher fiber contents. .