Optimization Analysis of Hardness Test for Powdered Pentaclethra macrophylla Pod /Bio-Epoxy Resin Based Brake Pad Composite Using Central Composite Design

Abstract

This work examined the optimization of hardness test for Powdered Pentaclethra macrophylla Pod /Bio-Epoxy Resin Based Brake Pad Composite Using Central Composite Design. The Pentaclethra macrophylla pod was manually cleaned and sun-dried for about three hours per day for three days. The sun-dried Pentaclethra macrophylla pod was later ovum dried at a temperature of about 110oC for three hours to achieve a constant weight and subsequently allowed to cool to room temperature. The ovum-dried Pentaclethra macrophylla pod was crushed to powder form using locally fabricated grinding machine and sieved. Part of the sieved powdered pod was carbonized in a heat treatment furnace at a temperature of about 950oC. Pre-impregnated process was used to prepare the brake pad composite samples. The weights of the powdered Pentaclethra macrophylla pods and bio-epoxy resin were varied while those of the lubricant, abrasives, friction modifier, catalyst and accelerator were kept constant The weights of the reinforcement i.e. powdered Pentaclethra macrophylla pods were varied between 10 wt. % and 50 wt. % at an interval of 10 wt. %. The formulation was poured into a wooden mould 50 mm × 50 mm × 8 mm placed in a hot platen press at temperature of about 180oC, a moulding pressure of 15MPa and a curing time of 5 minutes. Post-heat treatment of the composites was performed in a hot air oven for a period of 4 hours at 180 °C. The produced brake pads were evaluated for hardness in accordance to ASTM D785 standard using Rockwell Scale K hardness testing machine. The results of the test showed that 150μm particle size reinforced brake pad sample had higher hardness values of 105.7 and 106.4 at 20wt. % and 30wt. % respectively. This result was also confirmed by the Central composite design (CCD) where maximum hardness values of 107.31 and 107.63 were obtained at 20wt. % and 30wt. % respectively.