Influence of synthetic graphite powder on tribological and thermo-mechanical properties of organic-inorganic hybrid fiber reinforced elastomer-modified phenolic resin friction composites

Abstract

The present paper deals with the effect of synthetic graphite powder on tribological and thermo-mechanical properties of elastomer-modified phenolic resin friction composites reinforced with aramid pulp and lapinus fiber. Graphite containing four composites with variable graphite content e.g. 10, 20, 30, and 40 phr (parts per hundred resin) were prepared by hot mixing, followed by compression molding and post-curing at a high temperature. The friction coefficient and wear (volume) of the composites sliding against a cast-iron disc were measured using a laboratory-scale pin-on-disc tribometer. Graphite addition reduced the frictional fluctuations, although mechanical properties got deteriorated. The optimum composition (30 phr graphite loading) exhibited 1.5 times lower specific wear rate than the base composite (devoid of graphite). Graphite also increased thermal stability and thermal conductivity of the composites due to thermal conductive nature. The optimum composite showed a thermal conductivity of 0.53 W/m K as compared to 0.45 W/m K for the base composite. SEM analyses of the worn surfaces of the composites demonstrated different surface texture for different composites due to the varying extent of fiber-matrix de-bonding and wear debris formation. Interestingly, the amount of fiber-matrix de-bonding decreased with the increasing content of graphite.