Performance assessment of hybrid fibrous fillers on the tribological and thermo-mechanical behaviors of elastomer modified phenolic resin friction composite

Abstract

The tribological and thermo-mechanical properties of multi-component friction composites can be improved through the addition of hybrid fibrous components. The present article reports an empirical route for optimization of the relative proportion of two fibrous fillers viz. aramid pulp and lapinus fibers in a friction compound where the matrix component consists of phenolic resin modified with particulate acrylonitrile butadiene rubber powder. The effects of the change in net fiber concentration, as well as the relative proportion of these two fibrous components (aramid/lapinus) on different properties of friction composites like the coefficient of friction, rate of wear, thermal conductivity, and thermal decomposition were systematically investigated to get optimized composition. Aramid pulp concentration was changed from 10 to 40 phr (parts per hundreds of phenolic resin) whereas lapinus fiber from 50 to 300 phr. It was found that the 20 phr aramid pulp loaded composites show a stable coefficient of friction of 0.24 irrespective of the relative proportion of lapinus fibers. The specific wear rate of the composites having less fiber content is found to be better than that of composites with higher loading. However, the addition of fiber in composites improves thermal conductivity. In fact, the thermal conductivity of fiber loaded composites is ~ 2.5-fold higher than that of the unfilled one. The morphological analysis of the worn surfaces through the scanning electron microscopy reveals that the abrasive wear mechanism dominates during wear process.