In this work the feasibility of extracting cellulose from cotton, sisal and flax fibers, corn stover and rice husk by means of usual chemical procedures such as acid hydrolysis, chlorination, alkaline extraction, and bleaching was analyzed. Cellulose nanowhiskers from these sources, and from commercial cellulose, were produced by the acid hydrolysis of the obtained celluloses. The final products were characterized by means of Thermogravimetric Analysis (TGA), Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Scanning Electronic Microscopy (SEM) and Atomic Force Microscopy (AFM). The chemical procedure used to obtain cellulose nanowhiskers was effective in all cases but differences on the thermal stability, chemical composition, crystallinity and morphology were found due to the dissimilar nature of the different sources. Thus, this work demonstrates that the morphology and physical properties of cellulose nanowhiskers synthesized by the same conditions are strongly dependent on their source.

Cellulose and silica were obtained from rice husk by a multi-step procedure. Three different strategies including different alkaline and bleaching steps were evaluated by Fourier transform infrared spectroscopy (FTIR) in order to choose the sequence that combines the better conditions to obtain both subproducts simultaneously. The effects of the different steps on the structure and morphology of original material treated by the selected procedure were analyzed by X-ray diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The results suggest that it is possible to obtain both by-products with a simple procedure, giving an added value to this waste. Experimental MaterialsRH was obtained as a residue of rice industries of Entre Ríos (Argentina). Rice husk was extensively washed with distilled water to remove dust and other impurities. This operation was carried out several times at room temperature under vigorous stirring. After successive washings, rice husk was dried in an air-circulated oven at 80±1 o C and then crushed for 10 min using a ball mill (Pulverisette 7, Fritsh, Alemania). The final moisture content of the material was