Effect of phenolic resin content on performance of carbon fiber reinforced paper-based friction material

Carbon fiber reinforced paper-based friction (CFRPF) material is a new type wet friction material which has been used in automatic transmission. In this study, four kinds of CFRPF were prepared by paper-making process with cashew-modified phenolic resin. The resin contents ranged from 35 wt% to 50 wt%, and the effect of phenolic resin on properties of CFRPF was investigated. Porosity of the samples was measured by liquid permeation method. The degradation characteristics of the samples were analyzed using a thermal analyzer. The friction and wear properties were tested by a wet friction performance tester. Scanning electron microscopy (SEM) was also employed to study the wear mechanisms. Experimental results indicated that the reinforced fibers were dispersed uniformly in the phenolic matrix, containing some pores with different size. There were three stages in the thermal degradation of CFRPF, and the resin content had great effect on the degradation temperature at the second stage. Lots of tiny wear particles were found on the surface of the worn samples with lower resin content. Continuous friction film was formed on the worn surface with the increasing resin content, which efficiently enhanced wear resistance of the samples. Comprehensively, the samples with lower resin content (ranging from 35 wt% to 40 wt%) demonstrated better potential with high friction coefficient, excellent friction stability, good heat-resistance and reasonable strength.