Regenerated cellulose microspheres (RCM) with different diameters were prepared from cellulose solution using 7 wt% NaOH/12 wt% urea aqueous solvent pre-cooled to -12 degrees C by the sol-gel transition method via a "green" process. By varying the hydrophile-lipophile balance, the amount of the surfactants, the proportion of the water to the oil phase and the stirring speed, the mean diameter of the cellulose microsphere with nanoscale pore size could be controlled easily from 5 microm to 1mm. The structure and physicochemical properties of the microspheres were characterized by FT-IR spectroscopy, scanning electron microscopy, X-ray diffraction, mercury intrusion-porosimetry and particle size analyzer. The RCM microspheres exhibited spherical shape with the cellulose II structure. A preparative size-exclusion chromatography (SEC) column packed with the cellulose microspheres was used for the fractionation of a polyethylene oxide (PEO) in water, which indicated high efficiency for the fractionations and a large daily throughput of 4 g. Moreover, they had good adsorption capacity to dye particles through physical interaction. The cellulose microspheres would have potential applications in the fields of purification, separation and fractionation of polymers as chromatography packing and adsorbent both at laboratory and industrial scale.
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