Effects of graphite/partially carbonized hemp hurd particle mass ratios on tribological properties of polybenzoxazine composites

Abstract

This work aims to study effects of friction modifiers, i.e., synthetic graphite and carbonized hemp hurd (CHH) on thermal stability, dynamic mechanical properties, mechanical properties, and tribological performances of polybenzoxazine-based friction composites. Simulation of brake pad and disc brake by using ANSYS simulation program to study behaviors of the friction modifier filled-polybenzoxazine composites, i.e. pressure distribution and wear rate was also investigated. The results show that when the CHH is added to the polybenzoxazine composites, the tribological, dynamic mechanical, and mechanical properties were significantly improved because of some lignocellulose structure of the partially CHH. While, thermal property i.e., thermal degradation slightly decreased because the degradation temperature of lignocellulose is lower than the degradation temperature of synthetic graphite. From the simulation, the maximum pressure distribution was at the edge of the composite. At the lower temperature region, the behavior of the pressure gradient of the composite was occurred from the edge to the middle. When increasing temperature, the pressure gradient toward the middle was decreased. Moreover, wear rates obtained from simulation were closed to the wear rate from experiment with an error in the range of 7% which is within acceptable tolerance.