Mechanical Properties of a Bio-Composite Produced from Two Biomaterials: Polylactic Acid and Brown Eggshell Waste Fillers

Abstract

An option to reduce the exploitation and depletion of natural mineral resources is to repurpose current waste materials. Fillers are often added to polymers to improve the properties and lower the overall cost of the final product. Very few studies have assessed the use of waste brown eggshell powder (BESP) as filler in polylactic acid (PLA). The addition of mineral fillers in a polymer matrix can play an important role in the performance of a composite under load. Therefore, tailoring the amount of filler content can be a deciding factor as to which filler amount is best. The goal of this study was to investigate the effect of brown eggshells compared to conventional limestone (LS) powder on the mechanical properties of PLA composites. One-way analysis of variance (ANOVA) was used to carry out the statistical analysis on the average values of each composite mechanical property tested. Scanning electron microscopy (SEM) was used to view if there were any differences in the fractured surfaces. Overall, the LS performed marginally better than the BESP fillers. The highest ultimate tensile and ultimate flexural strengths for eggshell composites containing 32 µm fillers had values of 48 MPa (5–10 wt.% BESP) and 67 MPa (10 wt.%. BESP), respectively. Both the tensile and flexural modulus improved with filler contents and were highest at 20 wt.% with values of 4.5 GPa and 3.4 GPa, respectively. The Charpy impact strength decreased for all filler amounts. SEM micrographs identified changes in the fractured surfaces due to the additions of the filler materials. The ANOVA results showed statistically significant differences for the composite materials. After five weeks of soaking in distilled water, the composites containing 20 wt.% BESP fillers had the highest weight gain. The study demonstrated that waste brown eggshells in powdered form can be used as a filler in PLA composites.

Polylactic Acid Composites Reinforced with Eggshell/CaCO3 Filler Particles: A Review

“…Furthermore, by increasing the filler amount from 5 wt.% to 20 wt.%, the tensile and flexural strengths were reduced. Similar to the previous studies [5,116], mechanical properties, such as tensile and flexural strengths, as well as the modulus, were higher for PLA composites reinforced with 32 µm particles of brown eggshells or limestone. The studied mechanical properties were improved for PLA composites reinforced with limestone compared to the brown eggshell filler particles.…”

“…Similar trends for the tensile elastic modulus results were observed for flexural modulus, where it improved with greater filler loading for both filler types and particle sizes. In a related study, Cree et al [116] investigated the effect of filler type (brown eggshells and mineral limestone), loading amounts (5, 10, and 20 wt.%), and particle sizes (63 µm and 32 µm) to produce injection-molded PLA composites. In this research, the effect of brown eggshell as a filler was investigated, compared to the previous study using PLA/white eggshell composites.…”

“…The studied mechanical properties were improved for PLA composites reinforced with limestone compared to the brown eggshell filler particles. Experimental mechanical tests, such as tensile and flexural strength, and the modulus, were reported in recent studies [5,115,116]. The results were compared using Analysis of Variance (ANOVA) F-test method as a statistical analysis, where the variable adjusted was the relative filler concentration.…”

Experimental Analysis of Mechanical Properties of Banana Fibre/Eggshell Powder-Reinforced Hybrid Epoxy Composite

“…Through a process known as saponification, NaOH treatment aids in the removal of these impurities. These contaminants are broken down into soluble components by sodium hydroxide, making them simple to wash away [18]. Natural fibres that have undergone this washing process are cleaner and purer.…”