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.

The effect of calcined egg shell particles on the mechanical properties of epoxy resin had been studied. The egg shell was sun dried for 3 days and calcined at 800oC in an electrically fired furnace model KGVB. The calcined egg shell was ground in a locally fabricated pulverized machine and sieved using Sieve Model 567924/173281Endecotts in accordance with ASTM standard. Microwave digestion system and an inductively coupled plasma mass spectrometer (ICP-MS) were used to determine the chemical composition of the egg shell. The egg shell particles were mixed with epoxy resin to develop a composite casted by open mold casting. The flexural and hardness properties of the developed composite was determined using Universal Testing Machine model TUE-C-100, observing ASTM D790 standard and Rockwell Scale K hardness testing machine according to ASTM D785 respectively. The results showed that the calcined egg shell contained mostly CaO. Maximum flexural strength of 12MPa was observed at 25 wt. % egg shell particles. The highest hardness value of HRN 393 was observed at 20 wt. % egg shell particles. The produced composites may be applied where moderate strength is required.

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