SUGARCANE BAGASSE MICROFIBRIL CRYOGELS: DESIGNER, MECHANICAL PROPERTIES ANDE RESILIENCE IN WATER 

The global demand for sustainable products has increased, emphasizing materials and technologies that reduce environmental impact. Biomass presents a promising alternative due to its renewable nature and carbon neutrality1. Cellulose, the most abundant biopolymer in lignocellulosic biomass, can be processed in its fibrillar form or alternative morphologies through the regeneration of solubilized cellulose. In this study, cellulose microfibers (MFC) with residual lignin were directly isolated from sugarcane bagasse using a simplified oxidation process developed by our research group. Radical oxidation mediated by the catalyst 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) utilized 10 and 20 mmol/g of the oxidizing agent sodium hypochlorite. The MFC isolated with a lower degree of oxidation (MFC10) is yellowish due to a higher lignin concentration and contains larger particles. As the degree of oxidation increases (MFC20), the color becomes lighter, and the particle size decreases. Dispersions containing 3 and 6% w/w of MFC10 and MFC20, with and without mechanical treatment, were utilized to create cryogels, which possess potential applications in packaging and environmental decontamination. When dried, all the materials obtained have high porosity (above 90%) and certain physical integrity. However, they easily disintegrate in water, compromising their application. Therefore, these materials are being chemically cross-linked with citric acid (CA) and 1,2,3,4-butanetetracarboxylic acid (BTCA), in the presence of sodium hypophosphite (SHP). The results will provide valuable information into the influence of microfiber size, surface chemistry, and the cross-linking agent's nature on the porous materials' mechanical properties.