Preparation and characterization of cellulose regenerated from phosphoric acid.

Native cellulose has a highly crystalline structure stabilized by a strong intra- and intermolecular hydrogen-bond network. It is usually not considered as a good gelling material and emulsion stabilizer due to its insolubility in water. Chemical modification is generally necessary to obtain cellulose derivatives for these applications. In this study, we have shown that, by simply disrupting the hydrogen-bond network of cellulose with phosphoric acid treatment, the regenerated cellulose can be a good gelling material and emulsion stabilizer. Microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy analysis have confirmed that the regenerated cellulose is primarily amorphous with low crystallinity in the structure of cellulose II. Stable aqueous suspensions and opaque gels that resist flowing can be obtained with the regenerated cellulose at concentrations higher than 0.6% and 1.6%, respectively. Moreover, it can effectively stabilize oil-in-water emulsions at concentrations less than 1% by a mechanism that combines network and Pickering stabilization.