ABSTRACT
The effects of filler content and particle size on the mechanical properties of unsaturated polyester resin reinforced with rice husk-coconut shell particles have been studied. Rice husks (RH) and coconut shells (CS) particles were ground and particle sizes were obtained using 75, 150 and 300µm standard sieves. These particles were mixed in equal proportions by weight to form the filler component of the composite. Percentage by weight fractions of 0, 10, 20, 30 and 40 of the filler were blended with unsaturated polyester resin (matrix) by hand lay-up technique. Thirteen composite samples were produced from different formulations. Tensile, flexural, impact and hardness tests specimens were prepared based on ASTM standards. Tensile fractured surfaces were analysed with the help of Scanning Electron Microscopy (SEM) micrographs. It was observed that Ultimate Tensile Strength (UTS) decreased with filler loading with peak value of 19.691MPa at 10% composition of 150µm Rice Husk (RH)/Coconut Shell (CS). Flexural strength decreased with particle content. The filled samples had maximum value of 51.201MPa at 20% composition of 75µm RH/CS; the Unsaturated Polyester Resin (UPR) recorded 59.085MPa. Tensile and flexural moduli of elasticity followed irregular patterns. Peak values of 2316.248MPa and 3130.887MPa were obtained respectively. Impact tests did not show a specific pattern across all particle sizes. The closely related values peaked at 12.383J at 10% composition of 300µm RH/CS. Hardness values decreased with particle loading. The value of 204.833BHN obtained at 10% composition of 150µm RH/CS was the maximum. SEM micrographs showed low surfaces interactions, voids, agglomeration of fillers and shrinkage cavities. The fabricated composite can be used in the automobile and building industries.
