Abstract
The oxygen delignification of unbleached kraft pulps produced from industrial hemp stalks
and hemp ‘wood’ was studied, as well as the susceptibility of such pulps to bleaching. Hemp
stalk and wood pulp showed comparable susceptibility to delignification with oxygen in
alkaline media and good bleachability in the elemental chlorine free (ECF) and the total
chlorine free (TCF) bleaching processes. Good bleachability was also shown by hemp bast
fibre pulp. The final yield and intrinsic viscosity of bleached pulps produced from industrial
hemp were also determined and compared with the properties of pulps produced from tree
wood. It was found that the final yield of bleached hemp stalk pulp was higher than that of
conventional bleached birch- and pine papermaking pulps. However, the retention of high
intrinsic viscosity in hemp pulps can be achieved by varying the conditions of the oxygen
delignification and bleaching processes.