Physicochemical characterization of hemicelluloses from bamboo (Phyllostachys pubescens Mazel) stem

In this paper, hemicelluloses from bamboo (Phyllostachys pubescens Mazel) stem aged six months were sequentially extracted with hot water, 2% KOH, and 5% NaOH. The water-soluble hemicelluloses HI, and four alkali-soluble hemicellulosic fractions H-2, H-3, H-4 and H-5 were obtained, achieving a total yield of 59.60% based on the original hemicelluloses. Sugar composition analysis showed that the hemicelluloses were mainly composed of xylose (44.39-72.71%), arabinose (26.36-51.87%), ribose (0.93-2.72%), and uronic acid (0.29-5.27%). The structures of the hemicelluloses were determined to be mainly arabinoxylan, using the FT-IR and NMR techniques. The AFM images of fraction H-3 revealed a distribution of spherical nanoparticles with different sizes, while the fraction H-2 had helix rod and random coil feature. The SEM characterizations indicated that the fraction H-1 displayed spherical particles while the fraction H-3 had mainly flat particles at high magnification. Thermal stability was also analyzed using TG-DTG method and first-order kinetics model. (c) 2011 Elsevier B.V. All rights reserved.