2.1.2. Dispersion Procedures. Dispersion of a solution of
cellulose or a cellulose derivative in an immiscible solvent of
opposite polarity under high rotational speed results in the
formation of emulsions that can be stabilized with the aid of
surfactants.37 These emulsions contain droplet particles of the
dissolved polysaccharides that can be solidified to beads of the
same size, as described below. The diameter of the droplets
within the dispersion ranges from about 10 to several 100 μm
and is determined by the mixing speed, type and amount of
surfactant, ratio of hydrophobic to hydrophilic solvent, and
viscosity of the dispersion medium and cellulose solution.38,39
Consequently, cellulose beads prepared by dispersion are
roughly 10-times smaller compared to those prepared by
dropping techniques (Table 1). In contrast to procedures using
dropping techniques, no special equipment is required to
obtain products with reproducible properties. Thus, bead
preparation via dispersion has already been commercialized and
products with different sizes, from about 30−250 μm, are
available on the market (Figure 1a and b).12,13
2.1.2. Dispersion Procedures. Dispersion of a solution of
cellulose or a cellulose derivative in an immiscible solvent of
opposite polarity under high rotational speed results in the
formation of emulsions that can be stabilized with the aid of
surfactants.37 These emulsions contain droplet particles of the
dissolved polysaccharides that can be solidified to beads of the
same size, as described below. The diameter of the droplets
within the dispersion ranges from about 10 to several 100 μm
and is determined by the mixing speed, type and amount of
surfactant, ratio of hydrophobic to hydrophilic solvent, and
viscosity of the dispersion medium and cellulose solution.38,39
Consequently, cellulose beads prepared by dispersion are
roughly 10-times smaller compared to those prepared by
dropping techniques (Table 1). In contrast to procedures using
dropping techniques, no special equipment is required to
obtain products with reproducible properties. Thus, bead
preparation via dispersion has already been commercialized and
products with different sizes, from about 30−250 μm, are
available on the market (Figure 1a and b).12,13
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