Effect of blending cashew oil modified phenolic resin and nitrile rubber on thermal, mechanical, and tribological performance of friction materials

Abstract This study aims to investigate the effects of blending cashew nutshell oil modified phenolic resin and nitrile rubber (NBR) on the thermal, mechanical, and tribological performance of brake friction materials. The friction materials, which have a total binder of 25 wt% and different ratios of cashew nutshell oil modified phenolic resin and NBR, were prepared by hot press molding process. The experimental results show that NBR is beneficial to improve the hardness and compression modulus of the brake friction materials. The coefficient of friction (COF) is proportional to the wear rate, when the ratio of cashew nutshell oil modified phenolic resin and NBR is 13:12, the friction material has good heat resistance and exhibits excellent friction stability in the braking process, and the COF is steady between 0.420 and 0.448 at different braking speeds, while the wear resistance of material is optimal. The worn surfaces of the friction materials were examined by scanning electron microscope, and it was determined that the friction film is predominantly secondary plateaus, which can stabilize the COF and reduce the wear rate.