Conferência 3 - Materiais sustentáveis: estratégias para a fabricação de compósitos reforçados com nano-cristais de celulose através de impressão 3D

Cellulose is an attractive material resource for the fabrication of sustainable functional products, but its processing into structures with complex architecture and high cellulose content remains challenging. Such limitation has prevented cellulose-based synthetic materials from reaching the level of structural control and mechanical properties observed in their biological counterparts. To address this issue, we developed a simple approach to manufacture complex-shaped cellulose-based composites in which the shaping capabilities of 3D printing is combined with a wet densification process that increases the concentration of cellulose in the final part. Densification is achieved by solvent exchange, which induces attractive interactions between the cellulose particles. The effect of the solvent mixture on the final cellulose concentration is rationalized using solubility parameters that quantify the attractive interparticle interactions. Using X-ray diffraction analysis and mechanical tests, we show that 3D printed composites obtained through this process exhibit highly aligned microstructures and mechanical properties significantly higher than those obtained by earlier additively-manufactured cellulose-based materials. These features enable the fabrication of cellulose-rich synthetic structures that more closely resemble the exquisite designs found in biological materials grown by plants in Nature.