Alkali Treatment and Cellulose Nanowhiskers Extracted from Maize Stalk Residues

Abstract

The aim of this study was to investigate the use of effect of pulveriser and extraction of cellulosenanowhiskers (CNWs) on Maize stalks. Maize stalk residues were first subjected to a cutting mill for size reduction purified using mechanical, chemical extraction and bleaching. After chemical extraction, high quality cellulose resulted and cellulose nanowhiskers (CNW) were then extracted using chemical acid hydrolysis. The chemical compositions and mechanical properties of the maize stalk residues were examined before and after purification by using standard methods, Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Scanning electron microscopy (SEM) and thermo gravimetric analysis (TGA). The morphology and dimensions of the isolated cellulose nanowhiskers were characterized using atomic force microscope (AFM). The crystallinity index increased upon mechanical and chemical extraction. Thermal stability of cellulose derived from maize stalk improved with chemical treatment due to new functional groups introduced on the surface and enhancement in crystallinity. Highly dispersed cellulose nanowhiskers (CNWs) were successfully extracted from maize stalk residues with diameters ranging between 3 and 7 nm, length ranges between 150 - 450 nm, respectively.