Morphology, microstructure evolution and properties of resin-bonded palm kernel and coconut shell grain-based abrasive grinding

Abstract

This study examined the morphology and microstructural evolution of resin-bonded palm kernel and coconut shell grain-based abrasive grinding wheels and their physico-mechanical and tribological properties. Raw palm kernel shell (PKS) and coconut shell (CNS) samples were obtained, sorted, sun- and oven-dried, pulverised, and screened into fines of 250, 500 and 850 μm grain sizes, and blended at PKS to CNS mixing ratios of 1:0, 0:1, 1:2, 1:1 and 2:1, respectively. The blended grains, on a weight basis of the total aggregates, were bonded with 25 wt.% polyester resin and hardened and catalysed with 1.5 wt.% cobalt compound and methyl-ethyl ketone peroxide. The aggregates were moulded and compressed at a constant pressure of 18 MPa, ejected, and room-cured before being oven-cured to produce the wheels. The microstructural, water absorption, impact, flexural, hardness, and wear rate properties of the produced samples were evaluated. The properties studied were significantly influenced by grain sizes and mixing ratios of the PKS and CNS in the wheels. The least hardness value, 6.42 HRB, and wear rate, 0.44 mg/m were found in wheels produced from aggregates with pure PKS content with 850 and 250 μm grain sizes, respectively. The wheels' durability qualities suggest they could be used as abrasive grinding wheels, in particular, for wood cutting and finishing processes.