ABSTRACT
This chapter focuses on more delicate oxidation methods that can be used to prepare or modify cellulosic nanoscale particles. The oxidation of cellulose can be used to provide functional groups for chemical modification, to increase the water sorption of cellulosic materials, to protect the cellulose from acid hydrolysis, to increase fire retardancy and to render cellulose more bioabsorbable. NO2 oxidation can potentially be used for the preparation of cellulosic nanoparticles. The degree of oxidation correlates well with the calculated surface area of cellulose nanofibrils, which shows that 2,2,6,6-Tetramethylpiperidine-1-Oxyl (TEMPO) oxidation can be used to completely oxidise fibril surfaces. The oxidation time and the molar amounts of 2-Azaadamantane N-oxyl (AZADO) added can be significantly reduced using the AZADO/NaBr/NaClO system in comparison with the TEMPO system. Although NO2 and periodate oxidations have been used earlier at industrial scale, currently TEMPO oxidation is the only method that has been applied industrially.
