Eco-friendly Brake Friction Materials Containing Biomass

Biomasses, include jute fibers, walnut shells, hazelnut shells, are selectedand treated through some chemical and physical methods. Jute fibers areused as reinforced fibers, walnut shells and hazelnut shells as solidlubricant, other raw materials are also selected based on the principles ofnatural source, low costs, and low toxicity, a serial of eco-friendly brakefriction materials are prepared. Other raw materials include wollastonite,basalt fibers, zircon, barite, vermiculite and so on. CHASE friction testeris used to characterize the friction properties of samples, extensionevaluation method for formulations’ evaluation, scanning electronmicroscope (SEM) with energy dispersive x-ray spectroscopy (EDX) forobserving of surface morphology and elemental variation. Results are asfollows:(1)12%NaOH(W/W) solution can be used for the treatments ofwalnut shells and hazelnut shells, which remove hemicellulose andcellulose, contents of lignin and char yield increasing;(2) Treated walnut shells and hazelnut shells are used in frictionmaterials as solid lubricants, which can reduce and stabilized friction coefficients, enhance wear resistance. Volume content cannot too highsince they may thermal decompose in high temperature. Compare withgraphite, there is none negative effect for hazelnut shells and they aregood substitutes for solid lubrication;(3) Treated jute fibers can be used into friction materials which haveeffects of reinforcing and weak lubricant, they can reduce the frictioncoefficients and enhance wear resistances, their volume content cannot betoo high because of thermal decomposition;(4) Extension evaluation methods are used for the evaluation ofCHASE results for friction materials and determine the best volumecontent of walnuts shells and jute fibers are9.0%and5.6%, respectively;(5) Surface morphologies, variations of elements, hardness of testedand untested surfaces results showed walnut shells do not have obviouseffects for morphologies and elements distributions but can make thehardness lower because of thermal decomposition. Jute fibers canpromote the accumulations of iron elements.