Integrated manufacturing of REciclable multi-material COmposites for the TRANSport sector

This study investigates the mechanical and tribological properties of Kevlar-based composites filled with varying weight percentages (5%, 10%, and 15%) of nano fillers, specifically nanographene oxide (GnO) and silicon dioxide (SiO2), intended for automotive applications. The composites were fabricated using the conventional hand layup method. To assess the mechanical performance, including tensile, flexural, interlaminar shear strength (ILSS), and hardness, tests were conducted to evaluate material strength. Tribological characteristics were examined through wear and frictional tests carried out under different temperature conditions, ranging from 50 °C to 250 °C, with a sliding speed of 0.261 m/s, loads varying from 156 N to 315 N, and a test duration of 120 min. Comparative results revealed that the composite containing 10 wt% SiO2 exhibited superior mechanical properties, with a tensile strength of 372.45 MPa, flexural strength of 339.92 MPa, ILSS of 56.38 MPa, and a hardness rating of 92 HRB. These improvements were attributed to the inherent hardness and effective dispersion of SiO2, enhancing matrix-fiber bonding. In comparison to nano GnO, the Kevlar fibers loaded with 10 wt% nano SiO2 demonstrated the highest capacity for reducing wear (0.554?×?10?3m3/Nm) and frictional coefficients (0.083). Because SiO2’s stiff and strong structure offers a firm surface against the opposing material, it lowers friction and resists wear. The friction rate of the nano-fillers-loaded materials gradually increased with rising temperatures up to 200 °C and exhibited a significant increase from 200 to 250 °C. Conversely, Kevlar composites with 15 wt% SiO2 and 15 wt% GnO displayed higher wear rates, accompanied by pronounced fiber breakage and surface degradation, attributed to intense frictional forces generating thermal effects during sliding. Microstructural and structural characteristics of the hybrid composites were analyzed using high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), electron diffraction (ED), and X-ray diffraction (XRD). In summary, Kevlar composites with 10 wt% SiO2 filler demonstrated exceptional wear resistance, positioning them as promising candidates for automotive components prone to wear and friction, such as clutch systems, brakes, and engine parts.

» Reference: 10.1007/s12633-024-02977-y

» Publication Date: 05/04/2024

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