Development of eco-friendly brake friction composites containing flax fibers

Eco-friendly brake friction composites with good friction performance were developed. The raw materials utilized were selected according to eco-friendly criterion that natural products should be preferably chosen. The formulations are composed of plant flax fiber, mineral basalt fiber, and wollastonite as reinforcements, natural graphite as solid lubricant, zircon as abrasive, vermiculite and baryte as functional and space fillers, and cardanol-based benzoxazine-toughened phenolic resin as binder. To isolate the flax fibers, chemical and physical methods including drying, room temperature alkaline solution, and acid steam treatment were performed and fibers with micro-fibrillated structure on the surface were formed. A new cardanol-based benzoxazine synthesized by the reactions among cardanol, aniline, and formaldehyde was used as toughening for phenolic resin. The effects of both the content of treated flax fibers and friction temperature on friction performance, friction coefficient and specific wear rate, of the friction composites were evaluated by the extension evaluation method.