Ecological Transition in the Field of Brake Pad Manufacturing: An Overview of the Potential Green Constituents

Abstract

Nowadays, the drive for green products has undergone a rapid increase following the global ecoawareness and the severe regulations aimed at preventing the environment from further damage. The use of ecosafe constituents in materials for harsh applications, such as brake pad systems, can be a possible solution for reducing health hazards arising from particle release during braking. Based on this, the present study provides a bibliographic review of green alternative constituents for friction material formulation, focusing the attention on their influence on the tribological properties of the final composites. The traditional materials still used in commercial brake pads are shortly described, with the aim to provide an overview of the current situation. In the final part of the review, following the trend of circular economy, works dealing with the use of waste as an ingredient of friction materials are also reported. The whole literature screening points out that much work is still required to obtain completely green friction materials. Indeed, few works dealing with the phenolic resin replacement, proposing inorganic ecosafe materials such as geopolymers, are present. On the contrary, the use of natural fibers is widely investigated: palm kernel, flax, agave and aloe can be identified as promising constituents based on the literature results and the generated patents.

Progress in polymeric and metallic brake pads: A comprehensive review

“…Then, variation in Cu price would certainly force formulators around the world to achieve a substitute for Cu and its alloys, and thus, commercial brakes will be without Cu in the near years. 7 Rongping Yun et al 127 formulated sustainable brake pads to reduce the harmful environmental effects without Cu, Sn, Sb, and whisker materials. Based on the investigation, the position of brake pad samples from best to worst is in order of A, E, D, B, and C The sustainable and less costly sample E with high recovery capacity increased fade resistance and reduced sensitivity to speed exhibiting equivalent braking ability to that of the commercial break specimen A. Specimen A and E satisfies all benchmarks, but the other three samples B, C, and D largely due to their weak fade resistance could not clear the hot performance criteria.…”

“…Examination of brake pads from known brake pad makers—after market, exported after market, original equipment manufacturer (OEM). 7 The compressibility test examines the variation in thickness by the highest brake pressure. Going by industrial standards, the requirement is at least 25 kg/cm2.…”

“…Then, variation in Cu price would certainly force formulators around the world to achieve a substitute for Cu and its alloys, and thus, commercial brakes will be without Cu in the near years. 7…”

Study of the Influence of the Copper Component’s Shape on the Properties of the Friction Material Used in Brakes—Part One, Tribological Properties

“…Synthetic materials, in turn, have excellent strength properties, but the process of their production involves the use of aggressive chemicals, is dangerous, or generates toxic waste [ 14 ].…”

Composites in Vehicles Brake Systems-Selected Issues and Areas of Development

“…One of them may be origin, where natural and artificial can be distinguished. Natural materials are necessarily more ecological materials, especially if they are a by-product of another process, such as food production [ 20 , 21 , 22 ]. They can be of plant origin (stems, leaves), animal origin (fur, hair, shells) or mineral origin (e.g., zeolites) as well as metals and their alloys [ 23 , 24 , 25 ].…”