Innovative integration of pyrolyzed biomass into polyamide 11: Sustainable advancements through in situ polymerization for enhanced mechanical, thermal, and additive manufacturing properties

The incorporation of pyrolyzed biomass, i.e., biochar, in polymers can be viewed as a sustainable approach that reduces bio-waste in a smart way. Herein, various biochar concentrations were integrated into the biobased polyamide 11 (PA11) matrix via in situ polymerization. Scanning electron microscopy (SEM) micrographs demonstrated the homogeneous dispersion of up to 50 wt% biochar within the PA11 matrix, free from any phase separation, particle agglomeration, or crack formation. Consequently, there was a remarkable enhancement in mechanical and thermal properties. Notably, tensile strength and modulus increased by 35% and 72%, respectively, while the thermal decomposition process was significantly delayed with the incorporation of biochar particles. Furthermore, the viscoelastic performance of the PA11 matrix exhibited substantial improvement upon the addition of the filler particles. These impressive results verified the excellent interfacial compatibility achieved between the PA11 matrix and biochar, owing to the utilization of in situ polymerization. To demonstrate the potential application of these composites in additive manufacturing, a filament with a uniform diameter was fabricated from a composite comprising 50 wt% biochar. It was successfully employed in material extrusion to print a complex object. The resulting structure exhibited high shape fidelity, precise dimensions, and no noticeable defects. This groundbreaking strategy not only highlights the utilization of biochar as a sustainable filler but also underscores the efficacy of in situ polymerization in fabricating high-performance PA11/biochar composites for various demanding applications, including filament production for additive manufacturing.