Effect of surface treatments on tensile and flexural properties of carbon fiber reinforced friction material

The mechanical properties of a friction material primarily depend on the interfacial adhesion between all the ingredients of a friction material. In this work, a new friction material is developed by combination carbon fiber (CF), polymer matrix and other ingredients. The surface of CF is chemically inert and hydrophobic in nature and does not possess good bonding property with resin. Therefore, an attempt is made to improve the bonding strength between all the ingredients of a friction material. CF surface is modified by three different surface treatment techniques to increase hydroxyl or carboxyl groups on the surface. First, surface oxidation treatment, Second nitric acid treatment and third grafting multi walled carbon nano tubes functionalized (MWCNT-F) on CF surface. CF content after surface modifications is varied in wt % and mixed with remaining ingredients. Friction composite sheets are fabricated by using hand layup method. The resulting materials are characterized by SEM, TGA and FTIR analysis. MWCNTs-F on CF surface is observed. Twelve composite sheets with varying content of CF and surface treatment method is fabricated. Sample specimens are cut from the friction composite sheets to evaluate tensile and flexural properties of friction material. The best surface treatment method and optimum ingredients are selected for the improvement of tensile and flexural properties of friction material.