Preparation of Hydrophobic Cellulose Beads using Cellulose Dissolved in TEAH/Urea Solvent and AKD

To expand the application of hydrophilic cellulose beads, we developed a technique to prepare hydrophobic cellulose beads with alkyl ketene dimer (AKD). The cellulose solution was prepared by dissolving chemical pulp in tetraethylammonium hydroxide (TEAH)/urea solvent, followed by the addition of AKD to disperse it at room temperature. Cellulose beads were prepared by dropwise addition of the cellulose-AKD suspension into acetic acid solution, followed by washing and drying. The effects of AKD addition on the cellulose-AKD suspension and the properties of the AKD-modified cellulose beads were investigated. It was confirmed that the cellulose beads were chemically modified by AKD, resulting in enhanced hydrophobicity. The addition of AKD to the TEAH/urea/cellulose solution led to a reduction in viscosity and surface tension. Compared to unmodified cellulose beads, AKD-modified cellulose beads exhibited lower water retention value (WRV) and water absorption capacity, as well as increased oil absorption. They also exhibited relatively higher strength (lower deformation) when swollen in water.