Mechanical, Tribological, Thermal Conductivity and Flame Retardant Behavior of Natural Fiber and Biomass Derived Biochar Toughened Vinyl Ester Eco-Friendly Composite: A Sustainable Automotive Material

This research study focuses on the development of an automotive brake pad material that is environmentally sustainable. This is achieved by using rock wool fiber, silicon oxynitride (Si 2 N 2 O) friction material made from proso millet husk, and a biochar friction modifier obtained from tomato pomace. The main objective was to replace traditional friction modifiers such as alumina and graphite with affordable and environmentally friendly alternative supplies. The formulation of these unique friction modifier composites, which include rockwool fibers, is achieved by a hand layup method. Subsequently, they undergo post-curing at a temperature of [Formula: see text]C and are tested according to the guidelines set by the American Society for Testing and Materials (ASTM) standards. The results demonstrated that using Si 2 N 2 O as a friction modifier resulted in significant enhancements in the mechanical characteristics of the composites. The composite labeled as A4, which consists of a friction modifier composed of Si 2 N 2 O and biochar in a ratio of 12:8, demonstrated the greatest values for tensile strength (117[Formula: see text]MPa), flexural strength (163[Formula: see text]MPa), compression strength (129[Formula: see text]MPa), impact resistance (5.69[Formula: see text]J), hardness (80 shore D), and lap shear strength (22[Formula: see text]MPa). Similarly, the A3 composite, when using a 10:10 friction modifier, showed improved resistance to wear, with a specific wear rate of 0.013[Formula: see text]mm 3 /Nm and a Coefficient of Friction (COF) of 0.26. The addition of both Si 2 N 2 O and biochar particles increased the flame retardant properties of the composites. However, a higher concentration of Si 2 N 2 O had a more pronounced effect on boosting flame retardancy compared to biochar. In addition, the A5 composite with a high Si 2 N 2 O content (15:5) demonstrated the lowest thermal conductivity, measuring at 0.203[Formula: see text]W/mK. Therefore, the substitution of alumina and graphite with Si 2 N 2 O and biochar seems to be a beneficial approach that fulfills the criteria for brake pads in cars, while also decreasing environmental harm and aligning with the ideals of a circular economy.