Agricultural crop residues such as rice straw are promising globally available sources for nanocellulose production. Nanocellulose is typically isolated by extraction of pure cellulose from its sources followed by cellulose defibrillation. Pure cellulose is commonly isolated from biomass by removing waxes, lignin and hemicelluloses. In isolating cellulose from rice straw, we have further streamlined this process without eliminating hemicelluloses. The de-lignified rice straw (holo-cellulose) was directly defibrillated by TEMPO oxidation followed by mechanical blending to produce holo-cellulose nanofibrils (holo-CNFs) that contained little hemicellulose residues and exhibited similar morphology and thermal properties as CNFs defibrillated from pure cellulose by the same process. Under the same TEMPO mediated oxidation (5 mol/g NaClO/g materials, pH 10) and mechanical blending (30 min) conditions, the yield of holo-CNF to raw rice straw was slightly higher than that of regular CNF, but the holo-CNF exhibited lower surface charge (0.73 mmol/g CNF) comparing to CNF (1.34 mmol/g CNF). The holo-CNF production could be further optimized to increase its surface charge. In this paper, the surface characteristics and interfacial properties of holo-CNFs, their dispersion in aqueous and organic media as well as effects of drying will be discussed. The self-assembly behavior of these holo-CNFs will be compared with CNFs from pure cellulose.

Impact of hemicelluloses on the properties of defibrillated rice straw

247th National Meeting (2014)

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