Biochar as Sustainable Filler of Recycled Polylactic Acid (PLA): A New Generation of Processable Biocomposites

As an alternative to fossil-based polymers, polylactide acid (PLA) has stimulated a significant research effort in the past few years due to the demand for environmentally friendly products. Even though PLA is considered a sustainable or bio-based material, the long-term degradation in ambient conditions increases the volume of waste at end-of-life. To overcome this issue, PLA waste can be recycled to produce new manufactures; however, this approach does not always ensure the same mechanical properties as the original PLA. This study shows for the first time that adding biochar, a carbon material derived from biomass pyrolysis, enhances the processability and stability of composite recycled PLA. Composites are provided in 1, 2.5, and 5 wt% of the biochar filler, resulting in good processability, a higher modulus of up to 20%, and a higher stability to degradation in the presence of UV aging treatment with respect to the raw material. Additionally, DSC analysis shows a significant nucleation effect induced by the biochar that achieves 30% crystallinity from an essentially amorphous PLA.