Abstract:In this study, cellulose nanocrystals were prepared from peanut shells via pretreatments including alkali hydrolysis with sodium hydroxide, bleaching with sodium chlorite, and sulfuric acid hydrolysis. The obtained cellulose nanocrystals were characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and thermogravimetric analysis. The results showed that extensive amounts of hemicellulose and lignin from peanut shells were removed by alkali hydrolysis and bleaching, so that the content of cellulose increased from 43.84% to 86.56% and the molecular diameter of cellulose was between 10 and 30 μm. The nanocrystals were rod-shaped, between 90 and 210 nm long, with a diameter ranging from 5 to 25 nm. The molecular cellulose type I crystalline structure remained intact while the crystallinity gradually increased to 74.71% during the preparation of cellulose nanocrystals. The initial decomposition temperature of cellulose nanocrystals was low, when the temperature reached 500°C, the residue weight of cellulose nanocrystals was more than 30%. The cellulose nanocrystals prepared from peanut shells have potential application in biodegradable composites.
