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

摘要

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 H₁, and four alkali-soluble hemicellulosic fractions H₂, H₃, H₄ and H₅ 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 H₃ revealed a distribution of spherical nanoparticles with different sizes, while the fraction H₂ had helix rod and random coil feature. The SEM characterizations indicated that the fraction H₁ displayed spherical particles while the fraction H₃ had mainly flat particles at high magnification. Thermal stability was also analyzed using TG-DTG method and first-order kinetics model.