2. PREPARATION OF CELLULOSE BEADS
The preparation of spherical cellulose beads was described for
the first time in 1951.17 The materials, then named cellulose
pellets, were simply prepared by hand-dropping a viscose
solution into an aqueous coagulation bath. Since that report,
various procedures for obtaining cellulose beads with diameters
ranging from about 10 μm to 1−3 mm have been developed
using different solvents and techniques to obtain spherical
particles (Table 1). In principle, bead production can be
simplified into three steps: (i) dissolution of cellulose (or a
cellulose derivative), (ii) shaping of the polysaccharide solution
into spherical particles, and (iii) sol−gel transition and
solidification of the solution particles to beads.