PREPARATION OF POROUS LARGE BEADS OF CELLULOSE USING MIXED DILUENTS AND THEIR PROPERTIES

Cellulose diacetate in mixed solvents consisting mainly of dichloromethane-ethanol and mixed diluents, which contain ester and alcohol, was suspended in an aqueous solution of gelatine to form droplets. Dichloromethane-ethanol in the droplets was removed by evaporation to obtain cellulose diacetate beads containing the mixed diluents. The beads thus obtained were saponified and the mixed diluents were removed subsequently to prepare porous cellulose beads. The porous cellulose beads obtained were classified in the 74 approximately 297-mu-m, 297 approximately 500-mu-m and 500 approximately 1700-mu-m bead size ranges. The permeability into their porous cellulose beads was determined by eluting water soluble materials such as poly(oxyethylene) through a column packed with the gels and the maximum values of the exclusion molecular weight were 2.8 x 10(6), 1.0 x 10(6), 1.5 x 10(5), respectively. The porosity of the gels could be controlled by type and amount of mixed diluents. This method is suitable for the preparation of porous cellulose large beads.