Homogeneous isolation of nanocellulose from eucalyptus pulp by high pressure homogenization

Nanocellulose from eucalyptus (Eucalyptus robusta Smith) pulp was extracted by simply disrupting the hydrogen bond network of celluloses with high pressure homogenization (HPH). It was found that nanocellulose was 20-100 nm in diameter, and presented a narrower molecular weight distribution, lower thermal stability and crystallinity index. Fourier transform infrared (FT-IR) and solid state cross polarization magic angle spinning carbon-13 nuclear magnetic resonance (CP/MAS 13C NMR) were used to confirm the physicochemical properties of nanocellulose, suggesting that intra-molecular hydrogen bonds are entirely maintained. Meanwhile, the feasibility of high pressure homogenization for different cellulosic biomass materials was investigated using comparison of eucalyptus pulp nanocellulose, sugarcane (Saccharum officinarum) bagasse nanocellulose and cotton (Gossypium spp) nanocellulose. Results showed that eucalyptus pulp chains could be interrupted easily by the shearing forces for its harder texture, which was suited for high pressure homogenization. Other kinds of cellulose could also be well suited through controlling key parameters such as mechanical forces and treatment temperature in the process.