Investigation on the Effects of Uncarbonised, Carbonised and Hybrid Eggshell Filler Addition on the Mechanical Properties of Glass Fibre/Polyester Composites
Suhas S Kowshik, Sathyashankara Sharma, Sathish Rao U, Manjunath Shettar, Pavan Hiremath, Arjun Upadhyaya
Abstract
Waste eggshells were procured and processed to obtain uncarbonated eggshells and carbonized eggshells. Four variants of composites viz., unfilled, uncarbonated eggshell filled, carbonized eggshell filled and hybrid eggshell filled were fabricated using the hand lay-up technique. All three variants of filled composites were added 10 wt.% of eggshells. The idea of hybridizing the uncarbonated and carbonized eggshell fillers was also carried out. A mechanical stirrer was utilized for mixing the eggshells with unsaturated polyester resin. All four variants of composites were subjected to tensile and flexural strength tests as per the respective American Society for Testing and Materials (ASTM) standards. The tests showcased that all eggshellfilled composites possess better tensile and flexural strengths compared to unfilled composites. Carbonized eggshell-filled composites exhibited the highest strengths among all the composite variants considered followed by hybrid composites and uncarbonated eggshell-filled composites. The unfilled composites exhibited the least strength. The carbonized eggshell-filled composites showcased 43.9 and 34.14% higher tensile and flexural strengths in comparison with unfilled composites. Microscopic analysis of the failed specimens was conducted using a scanning electron microscope (SEM). The SEM images revealed that the eggshell filler was responsible for crack deviations and crack arrests contributing to the strength of the composites.