From dust to durability: Upcycling waste marble into resilient PLA composites

In this study, discarded marble dust (MD) was incorporated into polylactic acid (PLA), and the impact of the filler addition was assessed. The marble dust additives are incorporated into virgin PLA and recycled PLA at identical weight percentages, and the experimental results are subsequently compared. The differences in hardness, impact strength, flexural strength, and thermal stability were examined in both pristine virgin and recycled PLA and PLA-MD composites. The findings indicated that the flexural strength and impact strength decreased as a result of incorporating MD particles and the recycling process, whereas the hardness of the composites increased. Compared to virgin PLA, the flexural strength of the PLA-MD composite, recycled PLA, and recycled PLA-MD composites decreased by 5.91%, 7.74%, and 13.49%, respectively. Compared to virgin PLA, the hardness of the PLA-MD composite, recycled PLA, and recycled PLA-MD composites increased by 2.85%, 1.9%, and 5.78%, respectively. There was a notable decrease in the impact strength percentages for both the virgin and recycled PLA-MD composites. The TG analysis of virgin PLA-MD revealed a 50.87% increase in char residue relative to the unmodified virgin PLA. After recycling, the PLA-MD composites exhibited a 50.49% increase in char residue relative to the recycled PLA material.