The maize stem as a potential source of cellulose nanocrystal: Cellulose characterization from its phenological growth stage dependence

In this study the biomass content in different phenological growth stages (V3, V9, V13, Tasseling and R3) of the maize plant (Zea mays L.) was investigated. The biomass was quantified according to the TAPPI standards to obtain lignin, hemicellulose, alpha-cellulose, and ash contents. The cellulose content from biomass, ranging approximately from 21 to 37%, showed a dependent behavior on the phenological growth stages due to the plant physiology. Fourier Transform Infrared Spectroscopy measurements demonstrated the partial removal of lignin and hemicellulose contents in the alpha-cellulose obtention process. Scanning Electron Microscopy has confirmed the micrometer size of the raw samples and microfibrils, ranging from 100(similar to)560 mu m and from 40.4 +/- 1.5 up to 70.8 +/- 2.5 nm, respectively. The crystallinity index (CI) showed no dependence on the phenological growth stages and the X-ray diffraction patterns confirmed type I cellulose for the raw samples, and type II cellulose for the bleached fibers. The cellulose nanocrystals (CNCs) obtained by acid hydrolysis presented uniform morphology and the average length (66.7 nm), diameter (2.7 nm) and aspect ratio (24.7) were determined by a statistical analysis method.