(139e) Phenolic Catalyzed Hydroxyl Radical Oxidation for Cellulose Nanofiber Production

Hydroxyl radicals (�OH) can change the surface chemical properties of cellulose to produce charged carboxylates in production of cellulose nanofibers (CNF). While ozone gas is an efficient oxidizing agent, ozone alone is relatively ineffective in oxidizing cellulose surfaces. We show that the addition of phenols from lignin and its residual byproducts are effective hydroxyl radical promoters in aqueous solution. Our preliminary results indicate that lignin-derived phenolics are effective catalysts to activate ozone for oxidation of the cellulose surface thereby improving cellulose dispersion in liquid media. Changes in the zeta-potential of the �OH radical modified CNF suggested a colloidal stability after the chemical treatment. The initial 7% yield of CNF from the starting never dried pulp feedstock increased after removing the surface modified CNF by centrifugation/filteration and re-applying the chemical treatment to the remaining cellulose. The �OH radical-cellulose reaction needs to be carefully controlled to inhibit cellulose structural degradation which affects CNF characteristics. We propose a model that predicts surface characteristics as a function of phenolic catalyst loading, ozone consumption, and mechanical treatment.