THE WATER-RETENTION VALUES OF NEVER-DRIED ALKALI-TREATED CELLULOSES

The extent of swelling of refined and unrefined cotton linter, viscose pulp and paper pulp treated with various concentrations of NaOH from 4 to 20% at 20-degrees-C, then washed with water and never dried was m easured in terms of the water retention values (WRV). The treatment of unrefined fibers with alkali resulted in increase in WRV; the only ex ception was viscose pulp treated with 12 and 14% NaOH. Cotton pulp ref ined with 5% NaOH showed an increase in the swelling ability in water which increased with the concentration of alkali treatment, whereas fo r viscose and paper pulps the amount of water retained increased with alkali concentration up to 12% and 14% NaOH, respectively, then decrea sed with further increase in alkali concentration. For cotton and visc ose pulps refined with 20% NaOH, the alkali treatment increased the af finity of fibers to water up to alkali concentrations of 16% and 12% N aOH, respectively, then the WRV became more or less stable after treat ment with higher concentrations of NaOH. On the other hand, the paper pulp refined with 20% NaOH then treated with alkali concentrations fro m 10 to 20% showed decreased WRV.