Sustainable Brake Pad Composites: RSM-Based Optimization of African Oil Bean and Palm Fiber for Enhanced Performance

Abstract

This study addresses a significant gap in brake pad composite development by investigating the combined use of African oil bean seed pod (AOB) and palm fruit fiber (PFF), two abundant but underexplored agro-waste fillers. While these materials have been researched independently, their hybridisation within a single compressed fibre brake pad composition, as well as their synergistic impact on key performance metrics, have received little attention. The investigation utilized Response Surface Methodology (RSM) in conjunction with Design-Expert 13 software to systematically model and optimize the composition of the compressed brake pads integrated with African oil bean seed pod (AOB) and palm fruit fiber (PFF). The optimal weight percentages of the fillers were established as follows: 12.5982 wt.% palm fruit fiber (PFF), 37.4108 wt.%. Pentaclethra macrophylla, 33.4852 wt.% of an additive binder (comprising Epoxy and Hardener), and 15 wt.% for the grain sizes of both materials at 600 µm, with a treatment level set at 2. The empirical findings corroborated the successful augmentation of material characteristics, resulting in a flexural strength of 13.8307 N/mm², thermal conductivity of 0.12554 W/m·K, tensile strength of 4.1454 MPa, an exceptionally low wear rate of 1.79668E-06 mm³/m, and a desirability score of 1.000. The data obtained were juxtaposed with five distinct brake pad formulations, derived from a range of natural fibre-based alternatives. These parameters illustrate that African oil bean seedpods and palm fruit fiber utilized as filler constituents in the fabrication of a compressed fiber brake pad can function as a feasible substitute for traditional brake pads, thereby suggesting a potential contribution to sustainability and economic viability while improving braking efficacy. This study explores the valorization of agricultural by-products, highlighting their potential to foster innovative and more sustainable industrial practices.