A physico-chemical characterisation of new raw materials for microcrystalline cellulose manufacturing

A detailed physico-chemical characterisation of potential new cellulose sources (rice husk, hemp stalk, and coniferous needles), and microcrystalline cellulose (MCC) manufactured from them, was made in this work. The length and the width of the cellulose crystallites were determined by wide-angle X-ray scattering (WAXS), crystallinities were studied by means of WAXS and solid state cross polarisation magic angle spinning ¹³C nuclear magnetic resonance (NMR) spectroscopy, and the packing and the cross-sectional shape of the microfibrils were determined by small-angle X-ray scattering. When MCC was prepared from rice husks and hemp stalks an acceptable yield was obtained. Crystallinities obtained with solid state NMR spectroscopy and WAXS were highest for MCC prepared from hemp stalks, and lowest for rice husk MCC. The crystallite sizes of MCC samples studied in this work varied more than in those MCC samples which were prepared from conventional plant sources, and crystallite size and cellulose crystallinity were related. When taking into account rather high values of specific surface, hemp stalks and rice husks appear as a promising raw materials for MCC production.