Russian Journal of Applied Chemistry, 2013, Vol. 86, No. 1, pp. 96−103.
Pleiades Publishing, Ltd., 2013.
Original Russian Text © N.E. Kotel’nikova, Yu.V. Bykhovtsova, T.P. Shcherbakova, 2013, published in Zhurnal Prikladnoi Khimii, 2013, Vol. 86, No. 1,
AND POLYMERIC MATERIALS
Dissolution of Powder Celluloses in the Dimethylacetamide–LiCl
System and Physicochemical Characteristics
of the Regenerated Samples
N. E. Kotel’nikova
, Yu. V. Bykhovtsova
, and T. P. Shcherbakova
Institute of Macromolecular Compounds, Russian Academy of Sciences, St. Petersburg, Russia
Institute of Chemistry, Komi Scientiﬁ c Center, Ural Branch, Russian Academy of Sciences, Syktyvkar, Komi Republic, Russia
Received June 25, 2012
Abstract—Dissolution of powder cellulose samples from ﬂ ax wastes and wood pulps in the dimethylacetamide–
LiCl solvent was studied. The decisive factors of cellulose dissolution are the degree of chemical “purity” of cel-
lulose and the degree of polymerization. The cellulose I supramolecular structure of the initial samples transforms
into a mixture of polymorphous modiﬁ cations after dissolution and subsequent regeneration from solutions. The
samples regenerated from solutions consist of highly porous spherical particles. The powder samples degrade at
the ﬁ brillar level in solutions.
Direct dissolution of cellulose in the dimethylacet-
amide (DMAA)–LiCl system is known since the 1970s.
Search for new systems capable of dissolving cellulose
became particularly urgent for Russia in the 1990s be-
cause of the loss of cotton cellulose sources in the former
Soviet Republics of Central Asia. The possibility of pro-
cessing cellulose from other plant sources (wood, ﬂ ax)
by its dissolution opens prospects for the development
of new ﬁ bers and ﬁ lm materials.
Data are available on dissolution of cellulose samples
of various natural origins [cotton, sulﬁ te and sulfate co-
niferous pulps (pine and spruce), deciduous pulps (birch,
beech, eucalypt)] prepared under laboratory or industrial
scales, in DMAA–LiCl [1–12]. However, in spite of
numerous papers dealing with dissolution of cellulose
samples in this solvent, many questions concerning this
process remain to be answered. For example, no explana-
tions are given for the fact that, under similar dissolution
conditions, cellulose samples of different origins and with
different degrees of chemical “purity” dissolve in this
solvent to different extents. There are virtually no data on
the inﬂ uence of the lignin content of the samples on their
solubility. The supramolecular structure and chemical
properties of the samples regenerated from the solutions
are studied insufﬁ ciently. The properties of cellulose
materials prepared after regeneration from DMAA–LiCl
solutions are only little studied [1, 13].
The properties of solutions obtained by dissolving cel-
lulose samples and of ﬁ nal products regenerated from the
solutions appreciably differ depending on the dissolution
method. The diversity of procedures preceding dissolution
in this solvent and of dissolution methods indicates that
the search for the best dissolution conditions ensuring
formation of ﬁ nal products with preset speciﬁ ed func-
tional properties is being continued.
The aims of this work were to study how the degree
of polymerization of celluloses of various origins and
the lignin content affect the dissolution of the samples in
DMAA–LiCl, to prepare regenerated samples from the
solutions, and to study their physicochemical properties.
The samples isolated from the plant sources ﬂ ax ﬁ ber
(FF) and bleached deciduous and coniferous pulps were
studied. Short ﬂ ax ﬁ bers were linseed waste. Wood pulps
were prepared by kraft cooking at the Syktyvkar Timber
Plant ("Mondi", Syktyvkar) . Flax cellulose used