Various cellulose samples converted into cellulose III by two different ammonia treatments, either liquid or gaseous, were reacted with catalytic amounts of 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO), sodium hypochlorite, and sodium bromide in water. A substantial increase in the reactivity of cellulose III samples was observed in comparison to those in cellulose I, and a relationship between oxidation conditions and cellulose primary hydroxyl groups accessibility was directly established. For the characterization, we have used several methods, mainly (13)C NMR, methylene blue adsorption, FTIR, and conductometric titration. In all samples, the primary alcohol groups were selectively oxidized into carboxyl groups, provided the sodium hypochlorite is added dropwise and the reaction is performed at constant pH 10.

The goal of this work was to prepare cellulosic nanoparticles using different processing routes, viz. a combination of mechanical shearing, acid and enzymatic hydrolysis. It was shown that the enzymatic hydrolysis pretreatment of bleached sisal pulp helps the preparation of well individualized rodlike nanocrystals. The morphology of cellulose fibers and nanoparticles was determined by scanning and transmission electron microscopies, respectively. The main outcome of this study indicated the usefulness of the enzymatic treatment for cellulose nanocrystals production. The enzymatic treatment allowed production of a broad range of cellulosic nanoparticles. This investigation proved that the distinction between MFC and whiskers to describe such cellulose nanoparticles is not sufficient. Indeed, it appears essential to indicate the pretreatment performed.

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