Hydrodynamic and Surfactant Properties
of Sulfate Lignin Solutions
S. B. Selyanina, L. N. Parfenova, M. V. Trufanova, and N. V. Selivanova
Institute of Environmental Problems of the North, Ural Branch,
Russian Academy of Sciences, Arkhangelsk, Russia
Received June 28, 2010
Abstract—The effect of low-molecular-weight electrolyte additions on the behavior of sulfate lignins in
aqueous media was studied by capillary viscometry, tensiometry, and dynamic light scattering.
AND POLYMERIC MATERIALS
ISSN 1070-4272, Russian Journal of Applied Chemistry, 2011, Vol. 84, No. 8, pp. 1438–1441. © Pleiades Publishing, Ltd., 2011.
Original Russian Text © S.B. Selyanina, L.N. Parfenova, M.V. Trufanova, N.V. Selivanova, 2011, published in Zhurnal Prikladnoi Khimii, 2011, Vol. 84,
No. 8, pp. 1377–1380.
Technologies for processing of plant materials
frequently involve formation of soluble lignin
derivatives. These compounds exhibit noticeable
surface activity and are, at the same time, difficultly
biodegradable. Therefore, knowledge of their behavior
in solutions is important for characterization of both
production processes and environmental effects. As
applied to lignosulfonates, these aspects have been
examined in detail [1, 2], whereas considerably less
attention was given to the behavior in aqueous
solutions of sulfate lignins formed in the sulfate
process for producing fibrous intermediates, which is
today the most widely used process. This is due, in
part, to the fact that, in contrast to lignosulfonates,
sulfate lignins are soluble in aqueous solutions only at
pH > 7 and lose solubility in acidic solutions.
Furthermore, in base delignification procedures such
as the sulfate method, extractive substances pass into
the solution together with lignin fragments. Many
extractive substances exhibit high surface activity and
are capable of micelle formation. This fact complicates
studies of solutions of sulfate lignin. These problems
were examined in a number of recently published
papers [3–6], but in these studies the polyelectrolytic
nature of sulfate lignin macromolecules was not taken
into account. This feature can strongly affect the
behavior of sulfate lignin in solutions.
It is known  that the presence of low-molecular-
weight salts strongly affects the behavior of
polyelectrolytes in solutions and at phase boundaries.
For example, low-molecular-weight salts can shield
the polyelectrolyte charges, with the result that the
polyelectrolytic effect is suppressed and the polymer
macromolecule takes a more compact conformation.
Therefore, to describe the properties of solutions of
lignin-like polyelectrolytic substances, it is necessary
to take this factor into account, the more so as many
industrial and biological processes involving biopoly-
mers occur in the presence of low-molecular-weight
In this study we examined how additions of low-
molecular-weight electrolytes affect the hydrodynamic
and surfactant properties of solutions of sulfate lignin.
The lignin used in the experiments was recovered
from black liquors of classical sulfate delignification
of deresined spruce wood under laboratory conditions,
following the procedure described in detail in . For
the lignin sample obtained, we determined the
elemental composition (С : Н : О = 63.1 : 5.8 : 31.1)
and, using gel permeation chromatography, the weight-
average molecular weight (М
= 9700) and the degree
of polydispersity (М
= 4.0). Prior to studies, the
sulfate lignin sample was neutralized with NaOH.
Solutions were prepared by successive dilutions with
0.01 M aqueous NaOH or with a 1 M NaCl solution in
0.01 M aqueous NaOH.
The effect of the low-molecular-weight electrolyte
on the behavior of sulfate lignins in solutions was
characterized by variation of the surface tension σ of