Changes in zeta-potentials of amorphous cellulose particles with chitosan salts.

Abstract

Changes in ζ-potentials of amorphous cellulose and pulp particles by the addition of chitosan salts to suspensions were studied, where amorphous partcles were prepared from microcrystalline cellulose powder, linter cellulose, and softwood and hardwood bleached kraft pulps (SBKP and HBKP, respectively). Chitosan salts with 75 and 85% degrees of deacetylation and with Cl- and AcO-; as counter ions of the amine salts were used. The amounts of chitosan salts required for 0 mV ζ-potentials of amorphous smaples, which originally had ζ-potentials from -24 to -38mV, increased with an increase in carboxyl content of the original cellulose or pulp samples. These ζ-potentials became 0mV except for HBKP by the addition of chitosan salt lower than 0.1% on dry weight of amorphous samples to the suspensions, although HBKP required the addition of chitosan more than 0.2% in some cases. The effects of degrees of deacetylation, counter ions, and cation contents of chitosan salts, used so far, on ζ-potentials of amorphous samples were negligible or very slight. Compared with aluminium sulfate, ζ-potentials of amorphous samples were stable within 1 day after the addition of chitosan salts.