 The study investigated the effectiveness of two different types of fillers, industrial limestone, ILS, and waste eggshells, WE, in improving the mechanical properties of polylactic acid, PLA. The results indicated that the use of ILS fillers resulted in improved mechanical properties compared to e-fillers. However, the use of smaller particle sizes of ILS fillers resulted in even greater improvements in mechanical properties. Additionally, the study found that the use of ILS fillers resulted in lower water absorption than WE fillers. This article was authored by Duncan Cree and Majid Soleimani.