Multifunctional Biocomposite Materials from Chlorella vulgars Microalgae

Extrusion 3D printing of biopolymers and natural fiber-based biocomposites enables the synthesis of multifunctional and complex structures with a diversity of mechanical properties. However, this process faces significant challenges, including reducing material viscosity through high energy consumption, i.e., by heating, and harsh treatments to enhance stress transfer within the biocomposite. In this presentation, we introduce a systematic framework for synthesizing complex shapes using natural composite materials for sustainable and scalable processing. By utilizing <i>Chlorella vulgaris</i> microalgae as the biocomposite matrix, we optimize bioink and processing parameters to design multifunctional, lightweight, and hierarchical biocomposite materials through extrusion 3D printing. The proposed biocomposites maintain a continuous morphology of aggregated microalgae cells, capable of withstanding high shear forces during processing. Compression and bending tests assess the impact of printing variables and reinforcement concentration on mechanical performance. We additionally explore the effects of ambient conditions on the mechanical properties of the biocomposite. The <i>Chlorella</i> biocomposites demonstrate isotropic heat transfer under guarded heat flow and laser heating tests, functioning as effective thermal insulators. These materials show promise as substitutes for bulk polymers and wood, particularly in applications requiring a balance between thermal insulation and structural capabilities. Our methodology can be adapted to other microalgae strains, facilitating the large-scale fabrication of complex 3D structures.